PREVALENCE AND INTENSITY OF NEMATODE PARASITES OF Poecilia reticulata PETERS (1859) IN FOUR WASTEWATER DRAINS OF LAGOS STATE, NIGERIA Y BY AR R IB MOHAMMAD-MONZOOR ADEWOLE, AKILNWALE B.SC. (Sokoto), M. SC (IbadaYn) A Dissertation in the DepartmeIntT of Zoology, Submitted to the FaculSty of Science in partial fulfillment of theE reqRuirements for the Degree of MASTIEVR OF PHILOSOPHY UN of the N A UNIVERSITY OF IBADAN BA D I FEBRUARY, 2013. ABSTRACT Poecilia reticulata (guppy) a common ornamental tropical fish is found in many wastewater drains in Nigeria. Guppies feed on copepods which are intermediate hosts of some nematode parasites of culturable fish species. The restriction on the importation of ornamental fishes into Nigeria has enhanced the demand for local species, usually sourced from the wild. There is dearth of information on the parasites of ornamental fishes in Nigeria. This study was aimed at determining prevalence and mean intensity of the nematode parasites of P. reticulata from four waste water drains in Lagos State. Y Sampling was carried out monthly using a 2 mm mesh-sized scoop net along selected drains at Igi-Olugbin Street (A), Basil Ogamba Street (B), Ahmadu BelloR Road (C) and Adenaike Alagbe Street (D) between March, 2004 and February, A2005. The selected drains were contiguous to human habitation and industrial activities but each in different local government areas of Lagos State. Sixty female and sixtyR male samples were randomly selected from each drain for dissection and micrIoBscopy. Nematodes observed were identified using standard identification guides. Prevalence was determined as percentage infection in guppies examined. Inte nLsity was determined as total parasite count per host. They were calculated in relation to sex of guppies and drain location for sample collection. MeasuremeInTts Yof wastewater temperature, Dissolved Oxygen (DO), pH and transparency were done according to APHA methods. Drain depth was determined using a calibrated pole. Data was analyzed using chi- square test, ANOVA and Pearson correlationR coeSfficient. Nematodes recovered were EEustrongylides ignotus from peritoneum, Camallanus cotti from duodenum and anus, Capillaria pterophylli from intestine and Trichinella species from muscle. OuVt of 4,320 fish hosts examined, E. ignotus was the most prevalent parasite (3.6 %N) aInd Trichinella species the least prevalent (1.5 %). Prevalence did not differ significantly with sex and drain. Mean intensities were 0.3 ± 0.3 – 5.0 ± 1.8: males, 0 .3U ± 0.3 – 4.9 ± 1.8: females and 1.3 ± 1.3 - 7.0 ± 3.0: drains. Monthly mean intensity did not differ significantly with sex but differed significantly with drains (p < 0.05). Mean monthly physicochemical parameters for drains were: o -1 temperature, 25.A0 ± 1N.1 - 26.0 ± 1.1 C; DO, 7.8 ± 2.1 - 8.4 ± 1.8 mg l ; pH, 6.9 ± 0.5 - 7.3 ± 0.4; transparency, 3.5 ± 0.8 - 23.0 ± 3.6 cm and drain depth, 9.6 ± 2.3 - 14.8 ± 3.2 cm. There wDas no significant difference in mean monthly pH and DO across drains. HoweveAr, mean monthly temperature, transparency and drain depth were significantly diffeBrent across drain (p < 0.05). High correlation were observed at drain D between the 2 preIvalence of Trichinella species and wastewater DO (r = 0.8), between prevalence of 2 C. pterophylli and wastewater temperature (r = - 0.6) and also between mean 2 intensities of C. pterophylli and Trichinella species (r = 0.8). Prevalence and intensity of nematodes in Poecilia reticulata was low. However, the occurrence of parasites in the guppy requires appropriate treatment of fish before introduction into culture system. Keywords: Poecilia reticulata, Nematodes, Wastewater drains, Lagos State. Word Count: 497. ii ACKNOWLEDGEMENTS I acknowledge the contribution of all my teachers, student-colleagues and staff of the Department of Zoology, University of Ibadan who have helped me by giving technical assistance and providing University of Ibadan facilities at my disposal. Y Many thanks go to the Executive Director, Dr. E. A. Ajao, the DirectoRr and Head of Aquaculture Department, Dr Patricia O. Anyanwu, and the entire MaAnagement staff of the Nigerian Institute for Oceanography and Marine Research R(NIOMR) for permission and sponsorship of my M.Phil degree program. I praiseI thBe eagerness of all my colleagues at NIOMR to assist in this research work. L I however must acknowledge the very imporTtantY contribution, guidance and mentorship I enjoyed during the course of this studIy from my erudite supervisor Dr Adesola A. Hassan and the current Head of DepSartment of Zoology, Professor Adiaha A. Ugwumba who deserves my deep thanks aRlways. VEI UN AN AD IB iii CERTIFICATION I certify that this work was carried out by Mr. M.M.A. AKINWALE in the DepartmeYnt of Zoology, University of Ibadan. AR R LIB ITY S R -------------------------------------------------E-------------------------------------------------------- IVSupervisor N Dr. Adesola. A. Hassan, B. SUc (Ibadan), M. Sc (Jos), PhD (Lagos). S enior Lecturer, Department of Zoology, N University of Ibadan, Nigeria A D A IB iv TABLE OF CONTENTS Title Page. Abstract. ii Acknowledgements. iii Certification. iv Table of contents. v List of Tables. viii List of Plates. Y ix List of Figures. R x List of Appendices. A xi Chapter one. 1 1.0 Introduction. R 1 Chapter two. IB 6 2.0 Literature review. L 6 2.1 Habitat and morphology of P. reticulata. 6 2.2 Ornamental fish trade in Nigeria. Y 7 2.3 Ornamental fish as potential source of exotic pIaTrasites. 8 2.4 Challenges of sourcing ornamental fisRh thSrough aquaculture in developing 9 countries. 2.5 Occurrence of P. reticulata in waEstewater drains. 10 2.6 Bases For host-parasite relatioVnships. 11 2.7 Previously known nemaNtodeI parasites of Poecilia reticulata. 12 U CHAPTER THREE 3.0 N MATERIALS AND METHOD 13 A 3.1 StudyD area. 13 3.2 SAtudy location and design. 15 3.3I BField study. 16 3.3.1 Preliminary observations. 16 3.3.2 Fish sample collection and transportation. 16 3.3.3 Water sample collection. 16 3.4 Laboratory investigation. 21 3.4.1 Sample sorting and identification. 21 3.4.2 Parasite recovery. 22 3.4.3 Parasite count, preservation and identification. 23 3.4.4 Water Quality analysis. 23 v 3.5 Data analyses. 24 3.5.1 Determination of monthly frequency of occurrence. 24 3.5.2 Determination of prevalence, intensities, mean intensity and relative monthly 24 percentage composition. 3.5.3 Statistical Analyses. 25 3.5.4 Correlation Co-efficient. 25 CHAPTER FOUR Y 4.0 RESULTS AND OBSERVATIONS AR 26 4.1 Preliminary observations. BR 26 4.1.1 Sampling location. 26 4.1.2 Fish host features and behavior. I 27 4.2 Parasite types encountered. L 34 4.3 Monthly frequency of occurrence. Y 46 4.3.1 Frequency of occurrence pattern in relation to hTost sex. 46 4.3.2 Overall percentage frequency of occurrence paItterns. 46 4.4 Prevalence pattern. RS 46 4.4.1 Prevalence by parasite type. 46 4.4.2 Monthly prevalence by host sex. E 50 4.4.3 Drain-related nematode paraIsVite prevalence in P. reticulata. 50 4.4.4 Sex-related nematode pNarasite intensity in P. reticulata. 53 4.4.5 Drain-related nem aUtode parasite intensity in P. reticulata. 58 4.5 Relative percNentage parasite composition of infection. 58 4.5.1 Sex-related relative monthly percentage composition (rmpc) of nematode 58 parasite. A 4.5.2 DrainD-related relative monthly percentage composition of nematode parasite 61 pArevalence. 4.6I BMean physicochemical parameters. 64 4.6.1 Mean monthly physicochemical parameters. 64 4.6.2 Mean physicochemical parameters in drains. 64 4.7 Correlation co-efficient of physicochemical parameters with nematode parasite 66 prevalence and intensity in P. reticulata. 4.7.1 Correlation co-efficient of physicochemical parameters with nematode parasite 66 prevalence in P. reticulata 4.7.2 Correlation co-efficient of physicochemical parameters with nematode parasite 66 intensity in P. reticulata. vi 68 5.0 CHAPTER FIVE DISCUSSION 68 6.0 CHAPTER SIX 86 CONCLUSION REFERENCES RY 88 R A LIB ITY ER S V UN I N DAA IB vii LIST OF TABLES Table Title of Table Page Number Number 4.1 Number of infected male and female Poecilia reticulata. 47 4.2 Monthly prevalence of sex-related nematode parasites of Poecilia 49 reticulata. Y 4.3 Monthly prevalence of drain-related nematode parasites of Poecilia 5R1 reticulata obtained from each sampling location irrespective oRf sexA of sample. 4.4 Total count of nematode parasites in Poecilia reticulata obBtained 54 from the wastewater drains of four selected streets in LagIos State. 4.5 Monthly Sex-related mean intensity of nematodYe pa ra Lsites of 56 Poecilia reticulata. 4.6 Monthly drain-related mean intensity of neImTatode parasites of 59 Poecilia reticulata on drain locations iSrrespective of sex of host. 4.7 Means of monthly physicochemicRal parameters measured in drains 65 of selected streets throughout study. IV E N N U A BA D I viii LIST OF PLATES Plate Title of Plate Page Number Number 4.1 Lateral and comparative views of P. reticulata male and female 28 samples. 4.2 Dorsal view of cranium of male P. reticulata juvenile showing 29 Y characteristic eye views. 4.3 Dorsal view of cranium of female P. reticulata juvenile showing 3R0 characteristic melanin deposits. A 4.4 A ventro-lateral view of the gonopodium of male P. reticIuBlata R. 31 4.5 Lateral view of the caudal region showing chromophoLres deposits 32 on caudal region of male P. reticulata. Y 4.6 Lateral view of the caudal region of P. retIicTulata 33 4.7 Lateral view of an adult Camallanus cSotti obtained from P. 44 reticulata. 4.8 Ventral view of the posterior regioRn of a male Camallanus cotti. 45 IV E U N N DA IB A ix LIST OF FIGURES Figure Title of Figure Page Number Number 3.1 A section of Somolu/Kosofe LGA showing sampling site at Igi- 17 Olugbin Street. Y 3.2 A section of Surulere LGA showing sampling site on Basil 18R Ogamba Street. A 3.3 A section of Eti-Osa LGA showing sampling site on Ahmadu R 19 Bello Road. B 3.4 A section of Ikorodu LGA showing sampling site on AdeInaike 20 Alagbe Street. L 4.1 A drawing of lateral section of the anterior regioYn of 35 Eustrongylides ignotus fourth-stage larvae IobTtained from P. reticulata peritoneum. 4.2 Drawing of dorsal section of posterior Send of fourth-stage 36 Eustrongylides ignotus male larvaeR. 4.3 A drawing of dorsal section ofE posterior end of female 37 Eustrongylides ignotus fourth-stage larvae. 4.4 Lateral view of larva of TIrVichinella spp. obtained from P. 38 reticulata muscle tissues. 4.5 A drawing of latUeral Nview of the anterior region of Capillaria 40 pterophylli obtained from P. reticulata. 4.6 A drawing of l ateral view of a midsection of Capillaria pterophylli 41 obtained fNrom P. reticulata. 4.7 DrawiAng of ventral view of the distal end of Capillaria pterophylli 42 obDtained from Poecilia reticulata. 4.8 ALateral view of the gonadal section of a gravid female Capillaria 43 pterophylli with a fully mature barrel-shaped, bipolar embryo IB inset. 4.9 Sex-related relative monthly percentage composition (rmpc) of 62 nematode parasite prevalence in P. reticulata examined 4.10 Drain-related relative monthly percentage composition (rmpc) of 63 nematode parasite prevalence in P. reticulata examined x LIST OF APPENDICES Appendix Title of Appendix Page Number Number 1 White Egrets, Ardea alba, occasional visitors to a failed section of 113 wastewater drain on Basil Ogamba Street. 2 A wastewater drain on Ahmadu Bello Road with fully blocked 114 Y section leading to a gradual loss of habitat to wastewater fauna including P. reticulata. AR 3 Correlation co-efficient of nematode parasite prevalence Rin P. 115 reticulata obtained from Igi-Olugbin Street in relation to Bthe means of monthly physicochemical parameters of wastew atLer iIn drains. 4 Correlation co-efficient of nematode parasiYte prevalence in P. 116 reticulata obtained from Basil Ogamba STtreet in relation to the means of monthly physicochemicalS parIameters of wastewater in drains. R 5 Correlation co-efficient of Enematode parasite prevalence in P. 117 reticulata obtained froImV Ahmadu Bello Road in relation to the means of monthly physicochemical parameters of wastewater in drains. N U 6 CorrelatNion co-efficient of nematode parasite prevalence in P. 118 reticAulata obtained from Adenaike Alagbe Street in relation to the Dmeans of monthly physicochemical parameters of wastewater in Adrains. B 7 I Correlation of Mean intensity of nematode parasites in P. 119 reticulata obtained from Igi-Olugbin Street in relation to means of monthly physicochemical parameters of wastewater in drains. 8 Correlation of Mean intensity of nematode parasites in P. 120 reticulata obtained from Basil Ogamba Street in relation to means of monthly physicochemical parameters of wastewater in drains. xi 9 Correlation of mean intensity of nematode parasites in P. reticulata 121 obtained from Ahmadu Bello Road in relation to means of monthly physicochemical parameters of wastewater in drains. 10 Correlation of mean intensity of nematode parasites in P. reticulata 122 obtained from Adenaike Alagbe Street in relation to means of monthly physicochemical parameters of wastewater in drains. Y RA R LIB ITY RS E IV N N U AD A IB xii CHAPTER ONE INTRODUCTION Ornamental fish is that species of fish kept alive in transparent homestead aquaria, ponds and outdoor waterfalls for their aesthetic values. These values range from their characteristic colour, shape, size, exudates and behaviour in water. In general terms, ornamental fish is incomplete without invertebrates such as molluskYs and arthropods, corals, stones and live rocks having pores with encrusted colRourful algae and sessile invertebrates for natural biofilteration of aquaria, aquaAtic plants, special enclosures and associated visual effects (Livengood and ChapmanR, 2007). There is no record encountered in literature indicating abhorrence of aquaIriuBm fish keeping as a hobby or trade by practitioners of any particular culture, relig ioLn or law in any human society (Sanders, 1990). Ornamental fish species have beYcome ubiquitous all over the world and, therefore not surprisingly, many millionIsT of ornamental aquaculture and ecotourism enthusiasts are easily found among cShildren and young adults who made it at one time a hobby and at another a traRde. As a result, colourful adaptations of ornamental fish, their habitat and assVociaEted organisms are the subject of some cartoon movies and space fiction reporting.I Ornamental fish industNry (OFI) is currently valued at about 15billion United States Dollars (USD) ac coUrding to Larkin (2003); Wabnitz et al. (2003); Pelicice and Agostinho (2005); PNrang (2007); Wittington and Chong (2007) Moorehead and Zeng, (2010). OrnamenAtal Fish industry grew from an annual USD 34million export business in the earlyD 1950s (Conroy, 1975; Thurnberg, 1993 and Chapman et al., 1997) to a USD 28A2 million per annum export activity in 2006 (Livengood and Chapman, 2007). CoInBsidering sourcing, storage and conditioning of collected ornamental fish in the exporting countries where the industry has a ready poverty alleviating capacity; aquaria design and construction, specialized financing, retail and maintenance of resources in the destination countries estimations, as at 2006 indicated that global OFI was worth over USD 20 billion per annum (OFI, 2006). Contemporary ornamental fish trade is considered low-risk because there is relatively more astringency attached to the trans-border transfer of ornamentals. Ornamental fish involved in live fish trade are mostly wrongly considered low-risk 1 articles because of their aesthetic value and the ease with which they have enjoyed trans-border transfers through the ages. As a matter of fact, a social school of thought considers the possession, popularity and the acceptance of ornamental aquaculture, an index of economic well-being of any human population (Sharma et al., 2007). Alarmingly more important, however, is the forensic link made by Hulme (2009) in the sequence between globalization and gradual loss of biodiversity. A connection was made linking improvement of socio-economic well-being of developing nations, concept and practice of globalization through free trade whose main driver is unfettereYd transportation and emigration which voluntarily breaks down physical and biolRogical borders. Consequently, globalization liquefies natural biological isolatioRns, Aredefining species and niches that culminate in invasion of alien species and, ultimately, bioconservation trouble for our planet, Earth. He tagged the t reLnd Ia Bs Trade, Transport and Trouble. This means that if possession of ornamental fish iYs a ready reflection of social and economic status and means and, this would typiIfyT most human preferences under western civilization, it is no surprise that ornamSental fishes have become ubiquitous. Moreso, that they are portable and adaptRive to new climes in addition to being attractive, therapeutic and luxuriating to Ekeep at home and at work place irrespective of personal ideology. IV The most popular live-bNearing freshwater aquarium fish in the world demanding relatively less specializedU care to feed and reproduce is P. reticulata (Hargrove and Hargrove, 2006). ItN is t herefore easier to keep even as it survives adversity when accidentally or Aintentionally discarded into wastewater drains. It retains the highest freshwater oDrnamental fish import value into the US, while Nigeria with Democratic Republic of Congo remain the highest African export sources of ornamental fish into theI UBS ( AChapman et al.,1997). It is called the millionfish because of its small size, high fecundity and aggressive colonization of otherwise inclement water conditions (Meffe and Snelson, 1989). This fish was intentionally introduced in some wastewater drains for mosquito control (Manna et al. 2008; Anogwih and Makanjuola, 2010; Lawal and Samuel, 2010) but later became ubiquitous due to its attractive colour displays, space adaptation and temperament in captivity. P. reticulata has the ability to reproduce between 2 and 50 fries, within 21 to 30 days gestation period and in hard-water and o 25.5 - 27.8 C temperature conditions (Welcomme, 1988). Meanwhile, the female is 2 ready to conceive immediately after delivery of fry with the fry swimming, eating and avoiding predators immediately after live-birth from their mothers (Froese and Pauly, 2007). Meanwhile, Chervinski (1984) working separately from Shikano and Fujio (1997a) and Shikano and Fujio (1997b) reported that P. reticulata is capable of colonizing water having over 150% salinity than normal freshwater. It therefore follows that for adequate conservation of aquatic wildlife, commercial aquaculture, proper management of avian intermediaries of fin-fish and shellfish diseases to take place, the current disease situation of P. reticulata in wastewater drains is critical to the RlargYer Biosecurity of the Nigerian biome. Obtaining data on the diseases of feral P. reticulata from their loAcations in Nigeria could also serve as a proper scientific prelude to an adequate riskR identification, risk assessment and risk mitigation plan to local import substitutioInB and enhancement of this ubiquitous and well-sought after ornamental fish specLies as export material. Meanwhile, a vision is incomplete when it considers positive s cenarios at the exclusion of negative possibilities. This is why alluring cTonsYideration of the attractive possibilities of ornamental fish trade would fail reIality test if it discountenances a repeat of Eldredge (2000) report that imported P. reticulata escaped into drains and streams only to later out-compete indigenouRs fisSh species that were trophically related to the invading fish species in HawaiianE streams. The result is that the niches of the indigenous species were later left asV a gap unattended to. That was not all, parasites such as nematode Camallanus coItti and cestode Bothriocephalus acheilognathi that were hitherto not encountered in Hawaii streams became endemic because of the neo- tropical conditions of the streaNms there (Andrews et al., 1981; Font and Tate, 1994). In the light of the aforem enUtioned case, a critical knowledge gap becomes apparent (Lindholm et al., 2N005) because there is no record of nematode parasites of P. reticulata sinceA their introduction into Nigeria and their eventual escape into wastewater Ddrains and streams since the early 1970s (Welcomme, 1988 and Andrews, 1990). B AI Justification: The per capita diversity, distribution and intractability of nematodes amongst the parasites of fish is not in doubt (Anderson and May, 1979; 1985; Anderson, 1988; 1996; Moravec and Nagasawa,1998; Subasinghe et al., 2001; Lodge and Shrader- Frechette, 2003; Corfield et al., 2008) hence the choice of nematode parasites of P. reticulata for this study. Already obvious in previous cases elsewhere is the fact that setting a risk assessment framework not based on verifiable data leads to precautionary measures that are unnecessary or lead to relaxation of rules that may mislead into 3 allowing invasive species to tamper with a region’s biodiversity (Corfield et al., 2008). As a result and usually, only verifiable risk assessment form the basis for allowing a ban on importation of ornamental fish species from previously identified pathogen endemic areas by the WTO and OIE. Indeed, only this guarantees continuing security of ornamental fish export from an originating country. Unarguably, frequent risk assessments of standing parasite occurrence, load and distribution in wild and cultured ornamental fish stock is also the premium paid by developed economies for preventing difficult-to-verify origins of parasite outbreaks that culminate in brand daRmagYes impossible to subsequently indemnify. There is therefore a knowledge gAap in the prevalence and intensity of parasites of P. reticulata obtained from wastewater drains in Lagos State where established populations of this fish exists (RAnogwih and Makanjuola, 2010). IB However, the need to fundamentally secure Nigeria’ s Lliving aquatic borders from chance or deliberate infiltrations and aggressioTns oYf exotic pathogen invasions lead to the desirability of properly assessing the cIurrent status of the parasite and microbial loads of indigenous ornamental fish speScies and their major sister imports. Aim: R The aim of this study is to dVeteErmine the suitability of P. reticulata obtained from selected waste-water drains Iin Lagos, Nigeria that could satisfy requisite risk assessment parameters as diseaNse-free ornamental fish export. Objectives: U 1. To dNetermine types of nematode parasites of P. reticulata, their prAevalence and intensity. 2D. To investigate physicochemical parameters in relation to prevalence and A intensity of nematode parasite of P. reticulata. HyIpBotheses: 1. Null Hypothesis Ho: there is no significant difference between the observed nematode parasite prevalence and the expected parasite prevalence in male and female samples of P. reticulata. Alternate Hypothesis H1: there is significant difference between the observed nematode parasite prevalence and expected parasite prevalence in male and female samples of P. reticulata. 4 2. Null Hypothesis Ho: there is no significant difference in the nematode parasite prevalence in samples of P. reticulata obtained from the four drains. Alternate Hypothesis H1: there is significant difference in the nematode parasite prevalence in samples of P. reticulata obtained from the four drains. 3. Null Hypothesis Ho: there is no significant difference between the observed nematode parasite intensity and the expected parasite intensity in male and femaYle samples of P. reticulata. R Alternate Hypothesis H1: there is significant difference between the ob Aserved nematode parasite intensity and expected parasite intensity in male aInBd fe Rmale samples of P. reticulata. L 4. Null Hypothesis Ho: there is no significant difTfereYnce in the nematode parasite intensity in samples of P. reticulata obtained from theI four drains. Alternate Hypothesis H1: there is signRificaSnt difference in the nematode parasite intensity in samples of P. reticulata obtained from the four drains. E 5. Null Hypothesis Ho: NtherIe Vis no significant correlation between nematode parasite prevalence of PU. reticulata and the means of monthly physicochemical parameters of wastewate r obtained from the four drains. Alternate HyNpothesis H1: there is significant correlation between nematode parasite prevaleAnce of P. reticulata and the means of monthly physicochemical parameters oDf wastewater obtained from the four drains. 6. I B A Null Hypothesis Ho: there is no significant correlation between intensity of nematode parasites of P. reticulata and the means of monthly physicochemical parameters of wastewater obtained from the four drains. Alternate Hypothesis H1: there is significant correlation between intensity of nematode parasites of P. reticulata and the means of monthly physicochemical parameters of wastewater obtained from the four drains. 5 CHAPTER TWO LITERATURE REVIEW 2.1. Habitat and morphology of Poecilia reticulata: The fish Poecilia reticulata Peter (1859) is a member of the Phylum Chordata and belongs to the Class: Actinopterygii, the Order: Cyprinodontiformes, the Family: Poecilidae and the Genus: Poecilia. It is a tropical freshwater fish found occupyinYg estuarine drains, streams and rivers. The common name it is oftentimes called Ris the guppy, a name credited after Reverend R.J. Lechmere Guppy, the first PRresidAent of the Scientific Association of Trinidad. The guppy is also called topmIiBnnows or millions fish because it is prolific, very fecund and ubiquitous in the tropics (Meffe, 1989). They are also found in weedy ditches and canals turbid eLnough to exclude other fish species in lowlands and high altitude locations (ArthinYgton, 1989a). Courtenay and Meffe and Snelson (1989) reported a wide salinity toIlTerance for the guppy, it however survives in narrow temperature and water currenSt ranges. P. reticulata is an omnivore that has been found to subsist on zooplaRnktons, insects, lower invertebrates and detritus. Apart from constituting a popuElar ornamental fish species, they are used as biological control agents against soImVe aquatic insects that spread disease (Courtney and Moyle 1992; Courtney and MNoyle 1996). In Lagos, Nigeria, just as in California, United States of America , UP. reticulata is found in domestic and industrial waste water drains and channels N(Arthington and Lloyd, 1989). It is a verAy small fish of length ranging from 4.0 - 20cm. The entire body of the fish is elongate and moderately deep. The head is flattened; the entire body is covered with cycAloidD scales while the snout is short. The mouth is terminal, wide, oblique and proItBractible meant for picking, scraping, tearing and crushing food. There is a single dorsal fin with 6-19 soft rays; with their position relative to those of the anal fin. All fins have no spines (Rosen and Bailey, 1963). Anal fins have 9-soft rays with the third soft anal-fin rays unbranched in both sexes. The anal fins in males are modified into intromitent organ that is long, elongate and is called a gonopodium. This gonopodium is neither tubular nor scaled. There is also no sperm duct enclosed within it. Robin and Ray (1986) described P. reticulata as a fish whose pectoral fins have 9-16 soft rays, short, rounded and inserted on the high side of the body. Pelvic fins with 6 soft rays are 6 sub-thoracic in the adult females but thoracic in the males. The lateral line is composed of a series of pits running end to end along the side of the body. Sexual dimorphism is observed in P. reticulata with the males being smaller in size and shorter in length (2.5 - 3.5cm) than the females (4.0 - 6.0cm). While the males are more brightly coloured than the females, the latter bear the gravid spot anterior to the anal fin as a physical indication of bearing a young fish in the ovary. The gravid spot is however dorsal to the anal fin and at this stage the females have a prominently distended abdomen. Y R 2.2. Ornamental fish trade in Nigeria: A Mbawuike and Ajado (2005) reported twenty four ornamentaRl fish species excluding Poecilia reticulata known to be wildly sourced from thIe Bfreshwaters of the Osun River terminating at the Ibiajegbende fish landing settlem eLnt in Epe area of Lagos State. Ornamental fish is also available from the wild inY freshwater rivers of Lagos, Ondo, Ekiti, Ogun, Edo, Delta, Niger, Akwa Ibom, aInTd Abia States (Areola, 2003). A list of thirty ornamental fish species constituting Sexports from Nigeria was drawn up by Areola (2003) who conservatively estimatedR regular and documented exports receipts from Nigeria, excluding revenue fromV loEcal ornamental fish trade, to other countries to be in the region of USD 300, 000I per annum. This estimate is conservative because official ornamental fish cargo Nreceipt alone from commercial airlines for export within the period of March and UDecember, 2002 totaled over USD 411,000 (Areola, 2003). When these are contra sted with the USD 15 million gross annual continental ornamental fish expoNrts receipts from Africa in the year 2000 (Mouton et al., 2001) of which not leDss thAan about a third is known to annually originate from Nigeria (Areola, 2003) it becomes clear that Nigeria’s annual contribution to the sector is in multiples of miIllBion d Aollars. However, Nigeria exports as well as import ornamental fish. The first record of introduction of P. reticulata, the guppy, into Nigeria occurred in 1971 (Welcomme, 1988) and it was ostensibly to help in the biological control of mosquitoes breeding in wastewater drains of Nigeria. It was considered an emergency in order to reduce the man-hours lost to malaria which heavily debilitate the post-colonial era workforce of Nigeria at a period of increasing human population drift to Lagos at that time. Mosquitoes were to be controlled in wastewater drains where mosquito eggs and larvae were expected to be fed on by guppies. Evidence is scarce to 7 confirm if guppies had any appreciable impact in eliminating mosquito spread in the wastewater drains. Indeed, experiments conducted by Manna et al (2008) on the effectiveness of P. reticulata in the biological control of mosquitoes in the wild questioned its success because other preys may have been available in the wastewater drains to distract the predator. P. reticulata was however not introduced into Nigeria and the wastewater drains of Lagos State as an ornamental fish for its aesthetic values but in biodefence against mosquito spread. P. reticulata has since then spread beyond the drains of Lagos State where it was originally released, though currently, thoYse wastewater drains are some of the collection sources of P. reticulata for oArnamRental purposes in Nigeria. R 2.3. Ornamental fish as potential source of exotic parasites: IB While the danger of spread of diseases borne by ind igLenous ornamental fish species to aquatic wildlife and food fish is difficTult Yto perceive as urgent, the translocation of the pathogens and transfer of diseaseIs of exotic ornamental fish species constitutes clear and emerging danger to existing Sbalance between indigenous fish hosts and their associated biome (Vitousek et al., R1997; Kolar and Lodge 2001; Sakai et al., 2001; Dudgeon et al., 2006). CoVllateEral damage resulting from the ubiquity of ornamental fish everywhere culminIates in the single, most unhindered translocation of exotic parasites across the glNobe (Courtenay 1990; Courtenay and Stauffer, 1990; Courtenay and Moyle, 1 9U96; Fuller et al., 1999; Canonico et al., 2005). On record, ornamental fish consNtitutes the largest category of live animal and plant species moving across borders Aenjoying the most liberal application of quarantine and vetting regulations Dtoday (Corfield et al., 2008). Consequently, as the most immediate purveyoAr of accidental invasion of alien species in new niches, ethical concerns raised byI Bscientists, public sector administrators such as the International Union for Conservation of Nature, IUCN, (2001), Murray-Darling Basin Commission Native Fish Strategy (MDBC, 2006) and civil society about animal welfare abuses and zoonotic spread of exotic pathogens and parasites tends to find justifications. For instance, P. reticulata which has found a universal spread, a small benthopelagic omnivore, was known to be a native of Trinidad and Tobago, Brazil, Guyana and Venezuela (Lindholm et al., 2005 and Nico, 2010). As an invasive species it has been found to be hazardous and responsible for wiping out of native Cyprinids, 8 killifishes and damselflies by feeding on their eggs in their new climes of introduction as shown in Nevada and Wyoming, both in the United States (US). This information and those of other potential diseases of ornamental fish imports are made requisite for continuing trade relations by export destinations of Nigeria’s ornamental fish in the developed economies of the world. Many international marketing, freighting and Animal Health regulators such as the World Trade Organization (WTO), International Air Transport Association (IATA) and Organisation International des Epizootes (OIE) also require this information for export certifications and brand enhancements. TheYse requirements are to prevent potentially new infiltrations of their aquatic systeRm by previously unidentified nematode parasites of P. reticulata and ornamentRal fiAsh species into their holding, display and culture systems (United StaIteBs Department of Agriculture: USDA / American Public Health Information SLervice: APHIS, 2008). Incidentally, Nigeria is a member of, and signatory to WYTO, IATA and OIE treaties just as regular monitoring of existing and potential orTnamental fish disease conditions are parts of Nigeria’s relevant domestic laws such aIs Inland Fisheries Decree 108 of 1992 and Live Fish (Control of Importation) Act S209 of 1990. Obtaining data on the prevalence anRd mean intensity of nematode parasites of feral P. reticulata from their locatiVons Ein Nigeria could serve as a proper scientific prelude to an adequate risk identifIication, risk assessment and risk mitigation to local import substitution and enhanNcement. There is knowledge gap in the prevalence and mean intensity of nemato dUe parasites of P. reticulata obtained from wastewater drains in Lagos State. SettiNng a risk assessment framework not based on verifiable data leads to precautionaryA measures that are unnecessary or lead to relaxation of rules that may mislead intoD allowing invasive species to tamper with a region’s biodiversity (Corfield et al., 2A008). Usually, verifiable risk assessment is the basis for allowing for ban on imIpBortation of ornamental fish species from previously identified pathogen endemic areas by the WTO and OIE, and indeed, continuing security of ornamental fish export from an originating country (OIE, 2005). 2.4. Challenges of sourcing ornamental fish through aquaculture in developing countries: The continuing desire and requirement by destination countries especially those with well organized and developed economies for ornamental fish originating from 9 aquaculture rather than from the wild, justifiable as it seems on account of ensuring the sustainability of biodiversity of the relevant fish species, raises its own challenges. One advantage is the immediate impetus it creates for human capacity building in the development and spread of appropriate technology in the originating countries before export. Unfortunately, the relevant technologies currently existing in the destination countries are in pre-generic state and are not commercially mature for adoption in the originating countries thereby widening the gulf between supply and demand ends of the market. Apart from the fact that the relevant technologies are not immediately availabYle the intensive aquaculture method of raising fish and the attendant high stocking dRensity it employs in the maximization of space is a ready recipe for encouraginAg disease conditions resulting from many stress factors governing intensive cultRure conditions (Akinwale and Ansa, 2004; Akinwale et al., 2007). B LI 2.5. Occurrence of P. reticulata in wastewater drains: Y The fish P. reticulata Peters (1859) is very IcTommon in wastewater drains of many Lagos Streets (Anogwih and Makanjuola, S2010; Lawal and Samuel, 2010). The distribution often occurs in mature waste Rwater drains already laden with debris emanating from residential and indVustrEial activities surrounding the drains. Similar wastewater drain location had beeIn described for P. reticulata in California in the United State of America (CouNrtney and Meffe, 1989; Courtney and Robbins, 1989; Courtney and Stauffer, 1 99U0). Meanwhile, Ndifferent populations of guppies are known to have inter-racial isolation mechaAnisms (Baerends et al., 1955; Liley 1966) indicating intolerance of intraspecificD interaction. It is important to mention that P. reticulata is known to be exotic toA Nigeria and it is an ornamental aquaculture species reputed to have first been intIroBduced into Nigeria around 1972 (Welcomme, 1988) though originally native to the Caribbean (Nico, 2010). It would by the definition of the IUCN (2001) constitute an alien and invasive species in Nigeria. Water is as important as the material it conveys from place to place hence the quality of water is often described by the radical presence of materials or organisms in it. For aquatic organisms and sundry biota of economic importance to man, water can therefore be considered not only as the fluid of life but also as the medium or basin of life (Raven and Johnson 1996). Meanwhile, just as water cycle is a dynamic continuum terrestrial water bodies also commune with one 10 another. To this extent, aquifer water which serves as source of well water and basins from where potable water are sourced are never isolated from floods and waste drains nor are they exclusive of industrial and domestic effluents (APHA 1998 and Acho-Chi 2001). This is the same reason accidental fin and shellfish escapees reach wastewater drains when water is dislodged from earthen ponds or more intensive aquaculture and fish seed propagation systems (de Graff et al., 1995; Akinwale et al., 2004). As a result, exchange or translocation of parasite fauna and biocoenose between aquacultureR watYer impoundments and wastewater drains are not only made probable (Noble and Noble 1971) but become a practical and present danger in developing nations likAe Nigeria where waste water disposal systems are primordial (Boyd 1990; GenthRe and Seager, 1996; Forch and Bremann, 1998; Lacorchak et al., 1998 an d LObIi Bet al., 2002). The parasite ecology of fish communities in wastewater drYains should therefore be of interest to aquaculture and fish parasite evolution sTtudies (de Graff et al., 1995). Beyond this however, the potential of aquaculture inI further enhancing the intensity of newly established fish parasite fauna throughS massive stocking densities hitherto unavailable in waste-water drain fish ecosyRstems transcends the level of scenario to that of a nudging reality (Cole et aVl., E1999). The abatement of such an unpleasant prospect should therefore begin witIh the assessment of the existing parasite fauna of the major fish in waste water draNins and the existing type of association or potentially evolving parasitemia amo nUgst this major biota of the drains. 2.6. Bases for hoAst-pNarasite relationships: RelaDtionship between organisms and their environment in every community are governeAd by easily yielding rules and dynamics. Rules of co-habitation, toleration, coIntBention and subversion are established, re-assessed and redrawn to suit changing realities in resultant evolutionary directions that are in the main, adaptive rather than refractive, with no permanent interest constantly served (Noble and Noble, 1971). Again, as previously reviewed by Pigliucci and Murren (2003), is it possible that we have missed the small shifts in parasite evolution because evolutionary Scientists pay attention only to the impact of the big strokes on the even bigger canvas of evolutionary portraits? 11 Warren (1971) defined a parasite as an organism which lives in or on another organism (the host) and which depends on the host for its food, has a higher reproductive potential than the host, and is suspected of harming the host when present in large numbers. Parasites are therefore generally very spontaneous in reproduction while timing the host’s life cycle for the best transmission mode so that not only is the parasite’s interest enhanced between generations of its hosts, the parasite adapts more quickly to the changes in the host’s environment while inducing it to behave mostly Yin the parasite’s best interest. Often, large healthy fishes effectively sustain greater parasite populations Rbefore showing clinical signs of infection than smaller bodied fish like P. reticulAata in the same aquatic environment. However, because the skin and gill are the Rinitial landing sites for most parasites on fish hosts, parasites of small bodied IfiBsh species like P. reticulata that can adopt susceptible larger bodied fish sp ecLies in aquaria and in aquaculture tend to be more aggressive and successful inY establishing themselves on such new hosts to the detriment of the affected fish cuIltTure systems. S 2.7. Previously known nematode parasites Rof Poecilia reticulata. Previously published records of nemVatoEde parasites of P. reticulata include those of adult samples of C. cotti recoveredI from P. reticulata (Kennedy et al. 1987; McMinn 1990; Rigby et al. 1997; MoraNvec et al. 1999; Levsen, 2001, Kim et al. 2002 and Font 2003). Similarly, Capilla riUa philippinensis had also been obtained from P. reticulata by Ko (1995) while ThNilakaratne et al. (2003) recovered adult Capillaria spp. from P. reticulata surveyAed amongst ornamental fishes in Sri Lanka. Only larval samples of Aochotheca Dphilippinensis were obtained from P. reticulata in the Phillipines by Arthur and LumAanlan-Mayo (1997). IB 12 CHAPTER THREE MATERIALS AND METHOD 3.1. Study Area Lagos state is one of the most densely populated of all the states in Nigeria while Lagos city is reputed as one of the most rapidly growing cities of the world. YIt lies in the south western part of Nigeria and it consists of many metropolitan, urbaRn and rural areas. It is bordered in the north by Ogun state and the Bight of Benin paArt of Gulf of Guinea in the South. The Niger Delta is to the East of Lagos State buRt it is bordered to the West by Benin Republic. Lagos is currently the largest cityI iBn Nigeria with the highest concentration of sea ports and airports. However, Lag oLs is a city consisting of several islands separated by creeks but surrounded by mYany beaches which protect them from the damaging inundations of the AtlanticI TOcean which lie to the South of these Islands stretching over a 100 km to the easSt and west. Lagos Island is south west of the Lagos Lagoon while Victoria Island lieRs to the South east. They are linked by the 0 0 Bonny Camp Bridge. Lagos is found beEtween Latitude (lat.) 6 .35’N and 6.583 N to 0 0 Longitude (long.) 3 .45’E and 3.75I VE. Lagos retains a humidN tropical savannah climate with coastal sand banks, discontinuing patches o fU swamps, mangroves, heavy rain forests and secondary growths. Fadama IINI (2011) estimates that the vegetation of Lagos State consists of brackishwater sAwamps (10%), freshwater swamps (30%), rain forests (15%), regenerativeD growths (15%) and savannah bush fallows (25%). The brackishwater swamp, A found in Badagry, Ojo, Ibeju-Lekki, Epe and Ikorodu, is mainly characterized byI tBwo mangrove plants, Rhizophora mangle (the red mangrove) and Rhizophora racemosa (the black mangrove) plants with zonation consisting of nearshore having R. mangle, followed by R. racemosa inland and further by Avicennia africana, Laguncularia racemosa. Where the coast is lined by regosol soil, the palms of coconut, Prodococcu wateri and Ancistrophylum opacum dominate the vegetation of the immediate shore (Fadama III, 2011). Aquatic macrophytes such as Eichhlornia crassipes that bloom seasonally and others that remain in water perennially are found in the Ogun, Isheri Rivers as well as in the Lagos lagoon. 13 In the case of freshwater swamps into which rivers Yewa, Ogba, Isaku, Opamu, Ogun, Solodo, Berre, Owa, Aye, Owo and Oshun drain, wetlands resulting from the sporadic deluge of freshwater floods from these rivers sustain such vegetations as Kolanut, Oil palm, raffia and bamboo trees. Meanwhile, most local government areas of Lagos state have a bit of these freshwater swamps as the Lagos lagoon ramifies the viscera of Lagos State. The typical rainforests of Lagos State found in areas such as Igbokuta, Ijede, Agura and Agbede in Ikorodu LGA; Igbodu and Oko-Afo, Agbowa – Ikosi areas Yof Epe LGA are characterized by deciduous plants like Afromosia laxiflora, BRurkea africana, Daniella oliveri and Laoberlinia doka while the low and secondaAry growth forest areas found in Ibowon, Agbowa-Ejirin, Itoikin in Epe LGA,I IgBbog Rbo in Ikorodu LGA have plants like Alchornea cordifolia, Gmelina arborea a nLd Gliricidia sepium. Typical savannah of low shrubs, herbs and grasseYs spread over about 25% of Lagos terrestrial space are characterized by Oryza sativTa, Discorea esculenta, Zea mays and Chromolaena odoratum (Fadama III, 2011). I Fadama III (2011) also reported that theS geologic structure of Lagos State as mainly sedimentary but of the tertiary and qRuarternary state while the soil consists of ferrosol (18%), regosol (33%), with thEe hydromorphic and organic soil constituting remaining 49% of the soils of LaIgoVs State. Ferrosols require drainages; regosols are useful for coconut plantationsN, while the remaining alluvial and clayey soil requires fertilization and other coUnservation measures to enhance forestry, and agro-allied industry potential of the S tate. Lagos haAs a Nhigh rainfall profile marked by two heavy rain seasons initially between MaDy and July and then between September and October. Building Nigeria’s responseA to Climate change Project (2012) reported monthly rainfall means ranging beItwBeen 1567.2mm - 1750mm of every year. However, heavy floods result from the heavy rainfall peaks due to poor drainage of soil type characteristic of coastal lowlands found in Lagos. These two rain maxima often experience an interregnum of a few weeks called the August break spanning between August and September (monthly mean rainfall - 75mm) of the year while remaining rainfall tappers spasmodically to as little as monthly mean of 1.5mm in early January. Highest monthly atmospheric o temperature maxima of 30 C occur between November and December and also between February and March of each year. Thereafter, rains are replaced by disruptive 14 harmattan wind from the Sahara Desert that actually begins to gradually visit the Lagos area from late December till February of every year (BNRCC, 2012). The highest o monthly atmospheric mean temperature of 27 C was usually attained in March while o the lowest (25 C) was recorded in July (Fadama III, 2011). Lagos is currently home to many tribes of Nigerian origin but the original settlers were the Aworis and the Eguns while other parts of Lagos state especially to its northeast were inhabited by the fringe Ijebus as the first settlers. Though a cosmopolitan city located in the coastal region of southwesteYrn Nigeria, the growth of freshwater aquaculture as a result of increasing demand foRr fish and fish products has made aquaculture to be of great economic importaAnce to its citizens (Fakoya et al., 2004). R Commensurate demand for ground water has therefor e LalsoI Bincreased pressure on potable water (Grabow, 1996; Genthe and Seager, 1Y996; ehlossa and Muyima, 2000) in the face of failing public portals for domestTic and industrial use (Forch and Bremann, 1998). This consequentially limits theI quality of water employed in aquaculture throughout Lagos and expands the cSost of obtaining water which is one of the main factors of production in aquacultureR (Boyd 1995). IV E 3.2. Study location and designN: This study was c arUried out in Lagos State, Nigeria between March, 2004 and February, 2005. WaNste water drains on four different streets in four different local government areas of Lagos State were chosen for this study based on the human population dDensiAty and the adjacent industrial activity surrounding the selected portal drains sAerving as the habitat of Poecilia reticulata. The streets were Igi-Olugbin (Fig. 3.1I)B, Basil Ogamba (Fig. 3.2), Ahmadu Bello (Fig. 3.3) and Adenaike Alagbe (Fig. 3.4) streets. Each street was coded as: Igi-Olugbin (A); Basil Ogamba (B); Ahmadu Bello (C) and Adenaike Alagbe (D) for labeling of samples, tabulation and graphical illustration of nematode parasite occurrence as well as for calculating parasite prevalence and intensity. A stratified random sampling design was adopted with ten sampling stations identified along the length of each drain on the four selected streets. The global positioning system (GPS) co-ordinates of the sampling sites were acquired 15 while the sampling stations were spaced in such a way as to cover as many P. reticulata schools swimming in open wastewater in each of the drains. Sampling stations were identified on each street and spread along the length of waste water drains where P. reticulata were available while noting the descriptive particulars of the sampling areas, street landmarks, the Longitude and Latitude co- ordinates of sampling location, and the characteristics of the adjoining structures in terms of anthropogenic activities impacting on the wastewater drains. Thereafter, the mercury-glass thermometer, pH and Oxyguard meter fYor measuring temperature, pH and DO were inserted separately in wastewater tAo mReasure the corresponding physicochemistry. BR I 3.3. Field Study L 3.3.1. Preliminary observations: Y Visual identification and a pilot study of theI sTector and part of the wastewater drain where populations of P. reticulata were coSllected were conducted for each of the selected stations. This informed the decisionR as to the best approach in obtaining both fish and water samples for direct in VsituE measurement of wastewater physicochemical parameters. I Fish samples collecteNd from these drains were examined externally for significant indices of sex uUal dimorphism. Fish host sex was determined using features outlined by Rosen aNnd Bailey (1963), Houde (1997), Froese and Pauly (2007. The Global positioniAng system (GPS) co-ordinates of the drain were obtained using a handheld diDgital meter (Garmin - etrex brand). Sampling sites comprising of many stations Afor collection of both fish and water samples were spread along the length of waIstBewater drains while noting the descriptive particulars of the sampling areas, street landmarks, the Longitude and Latitude co-ordinates of sampling location, and the characteristics of the adjoining structures in terms of anthropogenic activities impacting on the abutting wastewater drains. 3.3.2. Fish sample collection and transportation: On sampling day, P. reticulata were obtained from the waste water drains with a 2mm mesh size scoop net from March 2004 to February, 2005. 16 RY BR A LI SI TY ER NI V U Figure 3.1.SectiAon oNf Somolu LGA Showing sampling stations (dots) at Igi-Olugbin Street (ArcGDIS mapping software by ESRI, 2011). A IB 17 RY BR A LI SI TY ER NI V U Figure 3.2.Section Nof Surulere LGA Showing sampling stations (dots) on Basil Ogamba Street (AArcGIS mapping software by ESRI, 2011). D A IB 18 AR Y R LI B TY RS I VE NI Figure 3.3.Section of Eti -OUsa LGA Showing sampling stations (dots) on Ahmadu Bello Road (ArcGISN mapping software by ESRI, 2011). A D A B I 19 RY BR A Y LI T RS I VE I Figure 3.4.Section of IkoUroduN LGA Showing sampling stations (dots) on Adenaike Alagbe Street (ArcGIS m apping software by ESRI, 2011). N A D A IB 20 Collection of P. reticulata samples was between 10.00am and 12.00noon, transported to the laboratory in a plastic bucket containing about fifteen liters of wastewater from the particular drain where collection occurred. 3.3.3. Water sample collection: A one liter glass beaker was used to obtain water samples from the more rigorously mixed portions of the wastewater that often coincide with the higher collection of P. reticulata schools in the drains. This is because the sampling strategy Yis to capture the main physicochemical parameters associated with the major regRion of wastewater where fish hosts mostly inhabit which were in line with thRe obAjective of these measurements. Water samples collected are analyzed for wastewater physicochemistry. LI B 3.4. Laboratory investigation Y Two hundred P. reticulata samples were collIecTted from each drain on the field. They were sorted by sex into sixty males and siSxty females in the laboratory through direct visual inspection for immediate diRssection under a dissecting microscope. Nematodes encountered in the gills,V muEscle tissues, viscera and Gastrointestinal Tract (GIT) of P. reticulata were extracteId from the organs. Those collected from Nwaste water drains were examined for the species and number of nematode par asUites in relation to the fish host sex, drain location of fish host before correlating thNem to the physicochemical parameters of the wastewater in the drain. The relatAionship of the occurrence of a particular nematode parasite and its number in each sex of the fish host obtained were later pooled for each of the wastewater dDrain locations. IB A 3.4.1. Sample sorting and identification: Sex determination followed the methods and criteria used by Haskins and Haskins (1951), Rosen and Bailey (1963), Houde (1997), Alexander and Breden (2004), Froese and Pauly (2007) in separating male P. reticulata from the female. Range of colour patterns on fish host samples were observed and applied in the preliminary determination of their sex. The colour patterns along the trunk region posterior through the operculum of fish all the way to the anterior region of the caudal 21 peduncle were noted. The structure of the anal fin of fish specimens were also observed if modified into an intromitent organ called the gonopodium for copulation in P. reticulata males. Guppy mark that distinguishes gravid female P. reticulata from immature females and males were also searched for to assist in sex determination. 3.4.2. Parasite recovery: Fish dissection was carried out using standard methods described by Southgate (1994). Saline was dispensed (0.9% sodium chloride solution) into a set of three smaYll watch-glasses. Before decapitation of fish sample, the opercula flap of each sampRle was raised with a pair of forceps to expose the gill arch, the opercula flap was Acut with a small pair of scissors, while gill filaments were also cut with the same pRair of scissors. The gills were then removed from the gill chamber, separated intoI twBo parts. One part was dropped into one of the watch glasses described abovYe w it Lh the other dry gill part dropped on a microscope slide. A drop of saline soluTtion was pipetted on the dry gill part mounted on the slide for microscopy. ThereafIter, the wet gill sample in saline solution of the first watch glass was then transferSred into a Perspex sample bottle. This bottle containing gill was shaken vigorously Rfor about ten minutes intermittently in this saline solution to free any available parasEite lodged within the filaments. Fluid resulting from this gill immersion was then IpVipetted onto another glass slide for microscopy of nematodes present. SubsequenNtly, the gill itself was directly lifted onto a different glass slide crushed between sliUdes before microscopic examination of nematode parasite lodged within its lamella . A fin ofA theN fish sample was severed with a pair of scissors and placed in another watDch glass containing saline solution before transfer into another Perspex bottle foAr dislodgement of nematode parasites for wet mount microscopy as done in the casIeB of the gills above. A dry fin is also mounted on a glass slide before dabbing with saline as described for the gills above. Scales lying posterior to the operculum of fish samples were shaved off with a scalpel to give access for cutting a flap of abdominal muscle tissue in order to reach the internal organs of fish sample under a dissecting microscope since P. reticulata is a particularly small fish with relatively small organs. The third watch glass was retained for any organ requiring re-examination in saline fluid. 22 The kidney, heart, gonads, liver, peritoneum, muscle tissue, alimentary canal and the anus of P. reticulata were very small. However, each organ excepting the peritoneum and anus was placed in a Petri dish before a wet-mount was made for each of the organs. Each organ sample was punctured, ripped open with the help of a pair of forceps and scalpel, dabbed with saline solution in the Petri-dish in which it was retained before mounting under the binocular microscope to examine tissue for nematode parasite. Nematodes sighted in petri dish are removed with a needle and placed on glass slide for further microscopic examination. Depending on the length Yof stay of fish sample on bench, a squash-sample of a whole organ was carriAed oRut by placing organs between two glass slides and squashed to visualize nematode parasites to stave rapid deterioration of fish samples. R IB 3.4.3. Parasite count, preservation and identification: L Each of the parasites were included as tally TentYries on tables drawn with a column each titled with the name of each identifieId nematode with rows indicating organ where parasite was lodged. They were couSnted and entered as tallies into tables separately for each sex and pooled for drain lRocations. The identification of nematodVe pEarasite larvae and adult followed thorough and full microscopic examination accoIrding to standard identification keys by Yamaguti (1961), Wilmott and ChabaudN (1974). Where photomicrographs taken with the aid of mounted digital camera wUere adjudged of less quality and too fragmented to represent whole microscope mNounts, Microsoft windows 7 Paint graphics software was used to draw parasite fea Atures. 3.4.4. WAateDr quality analysis: IBThe major physicochemical parameters measured for each of the sampling sites on the selected streets and road were water temperature (ºC), the pH, the dissolved Oxygen (mg/L), the Secchi disc-extinction and water transparency (cm) and the varying drain depth (cm) which indirectly measured the volume of water at each sampling station to the periodic accumulation of debris and therefore substrate in each of these drains. Temperature of wastewater was measured with a glass-mercury bulb in situ by dipping thermometer underneath water surface for 3 minutes before taking thermometer readings. The pH of water was measured with a pH/Conductivity meter model ARH-1 23 CE (Manufactured by Myron L Company, Carlsbad, California, USA) while dissolved Oxygen (DO) was measured by the use of electronic probe equipment (Oxyguard). Secchi disc was used to measure water transparency with an improvised white plastic plate, weighted with a small stone tied up in the middle of the plate with a five-meter length plastic-twine chord. Drain depth was measured with a calibrated pole. Physicochemical parameters taken monthly and all data were recorded in a table. Drains have concrete floors which do not substantially change except for erosion of the surfaces and the periodic deposit of debris from floods during rains anYd those backfills from monthly residential area sanitation exercises conducted throuRghout Lagos State. Drain depth, measured with a calibrated metal pole, was the Adifference between first impact on debris and ultimate drain floor. R IB 3.5. Data Analyses L 3.5.1. Determination of monthly frequency of occurrencYe: The number of months in which each nematoIdTe parasite species was recovered from P. reticulata was recorded as the monthSly frequency of occurrence for that species. These were derived from sex and dRrain-related nematode parasite prevalence tables. E IV 3.5.2. Determination of prevaNlence, intensity, mean intensity and relative monthly percentage composition: U Prevalence, eNxpre ssed as a percentage, is the number of individuals of a host species infectedA with a particular parasite species divided by number of hosts examined. IDntensity, expressed as a numerical range, is the number of individuals of a particulaAr parasite species (determined directly or indirectly) in each infected host. HoIwBever, mean intensity is the mean number of individuals of a particular parasite species per infected host in a sample (Margolis et al, 1982). Prevalence was determined for nematode parasites recovered from each sex of P. reticulata examined per month before determining prevalence of nematode parasites recovered for all P. reticulata pooled for drain location on each of the selected Streets irrespective of sex of fish host. Intensity was determined for nematode parasites recovered from each sex of P. reticulata examined per month before determining intensity of nematode parasites 24 recovered for all P. reticulata pooled for drain location on each of the selected Streets irrespective of sex of fish host. Therefore, where α = number of individuals of a host species infected with a particular parasite species; β = total number of host samples examined; µ = number of individuals of a particular parasite species and π = number of infected host samples Y Ω = total number of individuals of all parasite species found in infected hoAst sRample then: ( i) prevalence was calculated as = α / β x 100 R (ii) intensity was calculated as = µ / π . IB (iii) Relative monthly percentage composition = µ / Ω x 10Y0 L Mean intensity was calculated as mean ofI aTggregated intensity of parasite species categories ± standard deviation. RS 3.5.3. Statistical analyses: E Microsoft Excel (Office 20I07V) and SPSS 15 computer software packages were used for statistical analyses. N The Chi square anUalyses were used to determine if differences in treatment means were due to Nsampling chance in sex-based parasite prevalence and sex-based parasite intensity after basic descriptive statistics for each group of data. Two-way Analysis of DVarAiance (2-Way ANOVA) was used to determine drain-based parasite prevalenAce drain-based parasite intensity variations. 3.5I.4B. Correlation co-efficient: 2 Correlation Coefficient (r ) of the array of prevalence and intensity data of nematode parasite in P. reticulata to each of the array of physicochemical parameters of temperature, pH, DO, transparency and drain depth were determined. 25 CHAPTER FOUR RESULTS AND OBSERVATIONS 4.1. Preliminary Observations 4.1.1. Sampling location: Y Human habitation and anthropogenic influence of the contents of wasteRwater were evident in the contents and nature of sewer in the drains. EffluAents from bathrooms, kitchen wastes, bin wastes and materials swept into drains fRrom the tarred road are some of the constituents of wastewater and the mix i nL theI d Brain inhabiting P. reticulata. Activities from places such as fuel retail centersY, carpentry sheds and other commercial concerns that inadvertently release doImTestic and industrial wastes into wastewater drains influence the chemical statuSs of water that may impact on P. reticulata and its parasites. R The low walls of the concrete wEastewater drains on Basil Ogamba was vastly eroded in more than half of its lengIthV with many occasional predators such as the White Egret, Ardea alba, visiting rNegularly to prey on P. reticulata (Appendix 1). The concrete wastewater dra inUs on Igi-Olugbin Street, Ahmadu Bello Road and Alake Adenaike Street werNe mostly even, though with structural failure of the concrete walls especially arounAd the culverts intersecting adjoining roads and failed plumbing lines. Heavy floodDs observed in June, 2004 in all wastewater drains, brought the heavy collectioAn of debris. Overgrowth of aquatic macrophytes resulting in occlusion of the draIinBs ultimately leading to loss of habitat for such wastewater fauna as P. reticulata was observed (Appendix 2). The result was that no fish sample was available in the drains at the sampling locations in July, 2004 from the selected Streets. During the dry season, between November, 2004 and January, 2005, the drains were mostly dry and muddy in other places. The sector of drain where fish and water samples were then obtained was restricted to only shorter wastewater sanctuaries especially near entry-points of the drains closer to residences demanding greater sampling effort in all the drains. 26 4.1.2. Fish host features and behaviour: Many schools of P. reticulata were observed swimming in open wastewaters though some of them often hide under aquatic macrophytes as sanctuary from avian and sundry predators. Stalks of aquatic macrophytes and the flat and long fronded leaf of macrophytes provide shade and sanctuary from aerial predators. Male P. reticulata observed in this study were more brightly coloured than their female counterparts. Colour patterns observed on male fish samples ranged froYm orange, pink, red and black variegations of the regions posterior to the operculRum of fish. These run through the trunk all the way to the anterior region Rof tAhe caudal peduncle. Male P. reticulata were relatively smaller, slender and shorter in size while female P. reticulata samples were longer, broader and rotund Lin tIhBe posterior part of their abdomen (Plate 4.1). Gravid female P. reticulata bore guppy marks Ywhich have darkened spots around the posterior third of the abdomen indicatingI Tthe position of the head and eye buds of the developing embryo. Heavy depositioSn of chromophores were observed on the cranium of male P. reticulata juveniEles Runder microscopic examination (Plate 4.2) while their female counterparts hadI hVeavier melanin deposits rather than chromophores on the anterior cranial regionN (Plate 4.3). The gonopodium, a modified intromitent organ for transferring sperm into female P. reticulata, was supported by anal fin th th numbers 3, 4 and 5 Nas sh o Uwn on Plate 4.4. The 4 and 5 anal fins are not as acutely arched upwards Aas found in the other Poeciliids such as Gambusia spp. found in the wastewater Ddrains and streams where they sometimes co-exist with P. reticulata. This arching Aand the structure of the gonopodium as well as its distal end are distinguishing feaItuBres for these fish species. Caudal region colour dimorphism observed in the males was not seen in the females. Lateral view of the caudal peduncle of a male P. reticulata shows chromophores responsible for the multicolor pattern on male fish ramifying blood vessels and dermis of fish (Plate 4.5) which are greatly reduced in the case of their female counterparts (Plate 4.6). 27 Y RA R a LI B ITYS b ER IV Plate 4.1. Lateral and Ncomparative views of Poecilia reticulata (a) male with slender but multicolored cUaudal and abdominal regions and (b) female with broader abdominal and caudaNl regions. Bar (1cm). AD A IB 28 Y a RA R b LI B ITY f S e VE R d I Plate 4.2. Dorsal view of ccr aNnium of male P. reticulata juvenile with horizontal eye view (a - b); and right an glUed eye view. Chromophore deposits (e and f). (Mag. x 64.) AN BA D I 29 Y a RA R b LI B Y c T SI ER Plate 4.3. Dorsal view of craniIumV of female P. reticulata juvenile with heavier melanin deposits (a and b) andN superior, oblique and sub-terminal mouth (c). (Mag. x 64.) U N A D IB A 30 f AR Y e BR d I c L Y b ITS VE R NI a U Plate 4.4. A veAntroN-lateral view of the gonopodium of male P. reticulata st showing (a)D fleshy palp of gonopodium; (b) main gonopodium made of 1 anal fin; nd A rd th th(c) 2 anal fin part of gonopodium; (d) 3 anal fin; (e) 4 anal fin and (f) 5 anal finI.(BMag. x 160). 31 AR Y La IB R Y b SI T R Plate 4.5. Lateral view of the caudaVl regEion showing chromophores deposits ramifying blood vessels and dermis of a male IP. reticulata (a) peduncle and (b) fin (Mag. x 160). UN N AD A IB 32 a Y RA R IbB L IT Y Plate 4.6. Lateral view of the caudal reRgionS showing (a) dark pigmentation on peduncle and (b) fin of a female P. reticuElata (Mag. x 160). NI V U DA N BA I 33 4.2. Parasite types encountered Four nematode parasite species from four different nematode families were observed in P. reticulata samples examined. These were Eustrongylides ignotus Jagerskold 1909, Camallanus cotti Fujita 1927, Capillaria pterophylli Heinze 1933 and Trichinella species Railliet 1895. The parasite, E. ignotus, belongs to the family Eustrongylidae while C. cotti belongs to the family Camallanidae. The nematode, C. pterophylli, is a member of the family Capillaridae while Trichinella spp. was the onYly member of the family Trichinellidae encountered in this study. R The nematode E. ignotus was obtained from the peritoneum Rof inAfected P. reticulata. They were not encyted though the occurrence and infection of P. reticulata by E. ignotus caused external inflamation of the abdominal ca viLty oIf B the host fish. The third and fourth stage larvae of E. ignotus encountered were found ramifying the peritoneum of P. reticulata. This nematode was TusuYally bright red but atimes transluscent pink to faded-brown in colour with tranIsversely striated and thick cuticle. They were thread-like long bodied worms taperinSg to the anterior region with two rings of cephalic and labial pappilae (Fig. 4.1). ERach of the six labial papillae in the first inner ring of papillae was more poinVted Ewhile those of the outer ring of papillae were not as sharp at their tips. The anteriIor region of this nematode terminates in a protractile labium. The rounded posteriorN of a male E.ignotus larva is spatulate (Fig. 4.2) while that of the female is ov oUid (Fig. 4.3) in shape. There were caudal papillae at the posterior region of bNoth male (Fig. 4.2) and female larvae (Fig. 4.3) of E. ignotus. There weAre coiled larvae of Trichinella spp. lodged in the muscle fibers of P. reticulata. TDhese were found below darkened spots and lessions on the skin of the fish host. SoAme larval forms were found in the intestine of P. reticulata. The encysted larval forImBs in the muscle tissues of P. reticulata (Fig. 4.4) were often coiled unto themselves. Those lodged within muscle of P. reticulata presented with a dirty white but transparent colour upon dissection of infected P. reticulata host in contrasts with the dark pigmentation on the dermis corresponding to the lesion of encystment. This nematode possessed stichosomes on the ventrolateral sides of the oesophagus at the anterior half region of the nematode (Fig. 4.4). This worm tapers sharply at the anterior region terminating into a stylet but broadens widely and evenly to almost the tip of the caudal region when stretched and relaxed. 34 AR Y a R b B c LI d TY e SI f ER g NI V N U Figure 4.1.D A Adrawing of lateral section of the anterior region of Eustrongylides ignotus Afourth-stage larvae obtained from P. reticulata peritoneum showing (a) one of theI iBnner ring of labial papillae, (b) cephalic tip and (c) one of the outer ring of labial papillae (d) long oesophagus (e) inner cuticular layer (f) glandular oesophagus and (g) transverse striations (Mag. x 640). 35 AR Y BR Y LI IT a RS IV E U N b c AN Figure AD4.2. A drawing of dorsal section of the posterior end of male Eustrongylides ignIoBtus fourth-stage larvae showing (a) cuticular folds (b) caudal papillae and (c) outer cuticle (Mag. x 640). 36 Y RA R B LI ITY RSE a NI V ba N U b A a Figure A 4.3D. A drawing of dorsal section of posterior end of female Eustrongylides ignoBtus fourth-stage larvae showing (a) caudal papilla and (b) terminal anus (Mag. x 64I0). 37 AR Y R a b LI B c ITY d S e f ER g IV h UN AN Figure 4.4.D A drawing of lateral view of Trichinella spp. obtained from P. reticulata muscle Atissues showing (a) debris of host tissue, (b) posterior end, (c) cuticle, (d) intIesBtine, (e) , (f) stichosome, (g) oesophagus and (h) stylet at anterior end of worm (Mag. x 64). 38 The nematode parasite C. pterophylli belongs to the Class Adenophorea, subclass Enoplia, Order Trichurida, Family Capillaridae and Genus Capillaria. Adult C. pterophylli samples were observed in the infected P. reticulata dissected. This parasite is filliform in shape, transparent in colour and considerably long within the intestine of infected P. reticulata samples dissected. At the anterior end, the mouth is recrudescent without clearly distinct cephalic papillae (Fig. 4.5). There was a single line of slender stichosomes, each with a large centrally placed nucleus (Fig. 4.6). The male adult C. pterophylli has a distal end terminating in a prominent set of twin lobes around whicYh are a pair of circumcloacal papilla on the ventral side (Fig. 4.7). Each of thesRe two lobes also bears a papilla each. However, the male genital opening, the cloacaA, houses a sheated spicule where that of the female terminates in a vulvar with a pRartially raised upper lip through which mature embryo are extruded from the nemIatBodes’s uterus (Fig. 4.8). The maturing gelatinized string of embryos is set in a sin gLle file along the uterus. Some extruded embryos are found separately outside aduYlt worms in the intestine of some infected P. reticulata. The female C. pterophyIllTi are usually longer and broader than their male counterparts. Their eggs are ovaSl shaped with gentle striations on the apices and lateral wall of the mature embryoR but less so in the middle (Fig. 4.8). This worm has a direct life cycle in P. retiVculaEta. The general taxonomic deIscription of C. cotti is Phylum: Nematoda, Order: Spirurida, SubOrder: CamNallaninae, Superfamily: Camallanoidae, Family: Camallanida, and Genu s:U Camallanus. Adult C. cotti were observed lodged in the duodenum and anusN of infected P. reticulata hosts. This fusiform nematode, C. cotti, (Plate 4.7) has aA cephalic region that is somewhat dorsovetrally flattened with a buccal capsule thatD gives the anterior end of this nematode a golden brownish colour that contrastsA with the transparent but reddish colour of the remaining parts of the whole woIrmB. There is a frontally placed slit-like mouth opening from left to right at the anterior-most end of the parasite. On top and below this slit-like mouth is a pair of cephalic papillae. So also is one laterally placed trident structure indentured on both sides of the head with their triad prong end pointing anteriorly but their single arms pointing posteriorly. On the caudal extremity of this nematode, the male worm often maintain a dorsoventrally curved orientation with the cloaca located in the deeper cup of the folded distal part (Plate 4.8). The cloaca is surrounded by circumcloacal papillae and a triad of papillae at the distalmost end of the tail tip. 39 a b RY c A LIB R Y IT RS IV E Figure 4.5. A drawing of lateNral view of the anterior region of Capillaria pterophylli obtained from P. retic ulUata showing (a) indistinct mouth at anterior region (b) oesophagus and A(c) nNerve ring (Mag. x 64). AD IB 40 RY a RA LIB I YbT RS IV E N N U Figure 4.6. A Adrawing of lateral view of a midsection of Capillaria pterophylli obtainedA froDm P. reticulata showing (a) slender stichosome and (b) conspicuous nuclBeus of stichocyte (Mag. x 64). I 41 Y male R RA LI B Y Plate 4.10. A drawing of ventral T a I Sb c R d E IV UN Figure 4.7. DrawAingN of ventral view of the distal end of Capillaria pterophylli obtained from PoecilDia reticulata showing (a) circumclocal papilla (b) cloaca (c) papillae of ventral lAobe and (d) ventral lobe (Mag. x 64). IB 42 RY BR A a b Y LI IT c RS IV E N Figure 4.8. Lateral vie wU of the gonadal section of a gravid female Capillaria pterophylli obtainedN from Poecilia reticulata showing (a) vulva (b) uterus and (c) mature egg readyA for extrusion (Mag. x 64). BA D I 43 RY a b c RA LI B TY RS I d IV E UN AN Plate 4.7. LDateral view of an adult Camallanus cotti obtained from P. reticulata with (a)A buccal capsule; (b) position of trident; (c) oesophageal junction and (d) posiBtion of genital pore (MIag. x 40). 44 RY BR A LI a ITY b c b ER S V NI N U A Plate 4.8. VDentral view of the posterior region of a male Camallanus cotti showing (a) circumcAloacal papillae (b) cloaca and (c) triad of distal papillae at the posterior tip of theI wBorm (Mag. x 640). 45 4.3. Monthly Frequency of Occurrence 4.3.1. Overall Percentage Frequency of Occurrence Patterns: Out of the total of 4320 P. reticulata samples examined a total of 519 (12.0%) were infected with at least one, or a combination of, nematode parasite. E. ignotus had the highest overall percentage frequency of occurrence (PFO) of 30.0% with 156 P. reticulata infections while Trichinella spp. had the lowest overall percentage of 13.0% with 65 P. reticulata infections (Table 4.1). Y R 4.3.2. Frequency of Occurrence Pattern in Relation to Host Sex A The frequency of occurrence of each nematode parasite of P. reticulata iRs derived from the sex-related prevalence table (Table 4.2) according to the percenItBage of the number of months in which each parasite occurred in either sex of fiLsh host over the entire period of this study. Y E. ignotus: The frequency of occurrence of EI. Tignotus in male P. reticulata was seven months which constituted 28.0% in percenStage frequency of Occurrence while E. ignotus occurred in eight months in female PR. reticulata also constituted 28.0% in PFO (Table 4.2). E Trichinella spp: This occurIreVd in four months in male P. reticulata at 16.0% PFO but five months in femaleN P. reticulata at 18.0% PFO (Table 4.2). C. pterophylli: It oUccurred in seven months of the study with a 28.0% PFO in male P. reticulata buNt for eight months with 29.0% PFO in female P. reticulata. C. cotti: AIt occurred in seven months in both sexes with a 28.0% PFO in male P. reticulata bDut a 25.0% PFO in female P. reticulata. A student t-test revealed no significaAnt differences in the PFOs of the male and female P. reticulata (Table 4.2). 4.4I. BPrevalence Pattern 4.4.1. Prevalence by Parasite type: Out of the 4320 samples of P. reticulata examined 156 (3.6%) of them were infected by E. ignotus, 152 (3.5%) were infected by C. pterophylli, 146 (3.4%) were infected by C. cotti while only 65 (1.5%) of the P. reticulata samples were infected by Trichinella spp. 46 Table 4.1. Number of infected male and female Poecilia reticulata Male fish Female fish Street Street Y AR Month Nematode R March, 2004 Eustrongylides ignotus 1.0 0.0 1.0 2.0 6B.0 0.0 6.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 I0.0 0.0 4.0 0.0 Capillaria pterophylli 0.0 0.0 7.0 3.0 L 0.0 0.0 8.0 6.0 Camallanus cotti 0.0 0.0 4.T0 Y0.0 0.0 0.0 0.0 0.0 A pril, 2004 Eustrongylides ignotus 0.0 0.0 I0.0 0.0 6.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 0.S0 0.0 0.0 0.0 0.0 0.0 0.0 Camallanus cotti 0.0R 0.0 0.0 0.0 0.0 0.0 0.0 0.0 May, 2004 Eustrongylides ignotus E3.0 2.0 1.0 9.0 11.0 0.0 6.0 3.0 Trichinella spp. 3.0 0.0 2.0 0.0 3.0 0.0 1.0 2.0 Capillaria pterophylVli 1.0 0.0 0.0 1.0 5.0 1.0 3.0 0.0 Camallanus coNtti I 0.0 0.0 0.0 1.0 2.0 0.0 0.0 2.0 June, 2004 EustrongyUlides ignotus 0.0 0.0 1.0 12.0 0.0 0.0 2.0 8.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 CaNpilla ria pterophylli 9.0 5.0 1.0 0.0 2.0 3.0 0.0 0.0 ACamallanus cotti 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 July, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 D Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 A Capillaria pterophylli 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 IB Camallanus cotti 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 August, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 4.0 3.0 0.0 0.0 2.0 0.0 2.0 Camallanus cotti 5.0 0.0 0.0 11.0 5.0 0.0 0.0 2.0 September, 2004 Eustrongylides ignotus 3.0 0.0 0.0 6.0 3.0 1.0 2.0 2.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Capillaria pterophylli 5.0 0.0 0.0 4.0 5.0 0.0 0.0 1.0 Camallanus cotti 13.0 1.0 11.0 7.0 15.0 1.0 3.0 15.0 October, 2004 Eustrongylides ignotus 3.0 5.0 0.0 3.0 1.0 0.0 0.0 8.0 Trichinella spp. 0.0 6.0 5.0 2.0 0.0 0.0 5.0 3.0 47 Igi-Olugbin Basil Ogamba Ahmadu Bello Adenaike Alagbe Igi-Olugbin Basil Ogamba Ahmadu Bello Adenaike Alagbe Capillaria pterophylli 0.0 0.0 0.0 0.0 6.0 0.0 0.0 1.0 Camallanus cotti 1.0 3.0 1.0 2.0 2.0 5.0 0.0 6.0 November, 2004 Eustrongylides ignotus 0.0 0.0 0.0 1.0 0.0 0.0 0.0 1.0 Trichinella spp. 1.0 3.0 0.0 0.0 7.0 2.0 0.0 0.0 Capillaria pterophylli 1.0 0.0 3.0 0.0 1.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 2.0 0.0 0.0 0.0 6.0 D ecember, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Y0.0 January, 2005 Eustrongylides ignotus 0.0 0.0 0.0 0.0 0.0 0.0 0R.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 0.0 0.0A 0.0 0.0 Capillaria pterophylli 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 0.0 0.0 R0.0 0.0 0.0 F ebruary, 2005 Eustrongylides ignotus 7.0 6.0 8.0 1.0 I3B.0 2.0 8.0 2.0 Trichinella spp. 4.0 0.0 0.0 5.0 L 2.0 0.0 0.0 5.0 Capillaria pterophylli 7.0 5.0 8.0 Y1.0 6.0 17.0 13.0 2.0 Camallanus cotti 0.0 4.0 0.T0 0.0 2.0 6.0 2.0 4.0 RS I E V I N U N A D A IB 48 Table 4.2. Monthly prevalence of sex-related nematode parasites of Poecilia reticulata Nematode parasite RY RA IB Month Sex of fish host L March, 2004 Male 1.7Y 0 4.2 1.7 Female 5 1.7 5.8 0 A pril, 2004 Male T0 0 0 0 Female I 2.5 0 0 0 May, 2004 Male RS 6.3 2.1 0.8 0.4 FemEale 8.3 2.5 3.8 1.7 June, 2004 Male 5.4 0 6.3 0 Female 4.2 0 2.1 0.8 J uly, 2004 NIM Vale 0 0 0 0 Female 0 0 0 0 A ugust, 2004 U Male 0 0 2.9 6.7 Female 0 0 1.7 2.9 S eptember, 2004 N Male 3.8 0 3.8 13.3 A Female 3.3 0 2.5 14.2 October, 200D4 Male 4.6 5.4 0 2.9 A Female 3.8 3.3 2.9 5.4 November, 2004 Male 0.4 1.7 1.7 0.8 IB Female 0.4 3.8 0.4 2.5 D ecember, 2004 Male 0 0 0 0 Female 0 0 0 0 January, 2005 Male 0 0 0 0 Female 0 0 0 0 F ebruary, 2005 Male 9.2 3.8 8.8 1.7 Female 6.3 2.9 15.83 5.8 49 Euustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti 4.4.2 Monthly prevalence by Host Sex: In this study, the differences observed in the monthly sex- related nematode parasite prevalence throughout the study were not statistically significant. It is though noteworthy, that C. pterophylli had the highest monthly prevalence (15.8%) observed in female P. reticulata collected in February, 2005 as against the prevalence of 8.8% in male P. reticulata (Table 4.2). E. ignotus: The highest monthly prevalence observed in male P. reticulata (9.2%) was observed in February, 2005 while the highest prevalence (8.3%) in femaYle samples of P. reticulata was also obtained in May, 2004 (Table 4.2). R Trichinella spp.: For Trichinella spp., the highest monthly prevalenceA (5.4%) in male P. reticulata was observed in October, 2004 while that for IfeBmal Re P. reticulata (3.8%) was observed in November, 2004 (Table 4.2). C. pterophylli: The highest monthly nematode parasite pLrevalence 15.8% in the entire study was C. pterophylli observed in female P. rTeticYulata in February, 2005. The highest C. pterophylli monthly prevalence in male P. Ireticulata was 8.8% also observed in the February, 2005 samples (Table 4.2). S C. cotti: The highest monthly prevaRlence of nematode parasites in male and female P. reticulata occurred in SepVtembEer, 2004 and they were relatively comparable with each other unlike in the previIous cases already discussed. The highest prevalence was 13.3% in male P. reticulatNa and 14.2% in female P. reticulata (Table 4.2). U 4.4.3. Drain-relatedN nem atode parasite prevalence in P. reticulata: There weAre no statistically significant differences in the monthly drain-related prevalenc’e Din the nematode parasites of P. reticulata obtained from drains of the four selectedA streets. I Igi-Olugbin Street: C. cotti had the highest drain related nematode parasite prevBalence of 23.3% amongst all the nematodes observed in P. reticulata samples obtained and examined throughout the study and it was observed in samples obtained from Igi-Olugbin Street examined in September, 2004 (Table 4.3). The highest prevalence of E. ignotus was 11.7% in May, 2004 while that for Trichinella spp. was 6.7% in November, 2004. The highest drain-related prevalence of C. pterophylli was 10.8% in February, 2005 (Table 4.3). 50 Table 4.3 Monthly prevalence of drain-related nematode parasites of Poecilia reticulata obtained from each sampling location irrespective of sex of sample Month Nematode parasite Y March, 2004 Eustrongylides ignotus 5.8 0.0 R5.8 1.7 Trichinella spp. 0.0 0.0A 3.3 0.0 Capillaria pterophilli 0.0 0.0 12.5 7.5 Camallanus cotti 0.0 R0.0 3.3 0.0 April, 2004 Eustrongylides ignotus 5B.0 0.0 0.0 0.0 Trichinella spp. I0.0 0.0 0.0 0.0 Capillaria pterophilli L 0.0 0.0 0.0 0.0 Camallanus cotti Y 0.0 0.0 0.0 0.0 May, 2004 Eustrongylides ignotusI T 11.7 1.7 5.8 10.0 Trichinella spp. S 5.0 0.0 2.5 1.7 Capillaria pterophilli 5.0 0.8 2.5 0.8 Camallanus coRtti 1.7 0.0 0.0 2.5 June, 2004 EustrongyElides ignotus 0.0 0.0 2.5 16.7 TrichIiVnella spp. 0.0 0.0 0.0 0.0 Capillaria pterophilli 9.2 5.0 0.8 0.0 Camallanus cotti 0.0 0.0 0.0 1.7 July, 2004 UNEustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 N Capillaria pterophilli 0.0 0.0 0.0 0.0 A Camallanus cotti 0.0 0.0 0.0 0.0 A ugust, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 AD Capillaria pterophilli 0.0 5.0 2.5 1.7 I B Camallanus cotti 8.3 0.0 0.0 10.8 S eptember, 2004 Eustrongylides ignotus 5.0 0.8 1.7 6.7 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophilli 8.3 0.0 0.0 4.2 Camallanus cotti 23.3 1.7 11.7 18.3 O ctober, 2004 Eustrongylides ignotus 3.3 4.2 0.0 9.2 Trichinella spp. 0.0 5.0 8.3 4.2 Capillaria pterophilli 5.0 0.0 0.0 0.8 Camallanus cotti 2.5 6.7 0.8 6.7 November, 2004 Eustrongylides ignotus 0.0 0.0 0.0 1.7 Trichinella spp. 6.7 4.2 0.0 0.0 51 Igi-Olugbin Basil Ogamba Ahmadu Bello Adenaike Alagbe Capillaria pterophilli 1.7 0.0 2.5 0.0 Camallanus cotti 0.0 0.0 0.0 6.7 D ecember, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophilli 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 0.0 January, 2005 Eustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophilli 0.0 0.0 0.0 Y0.0 Camallanus cotti 0.0 0.0 0.0 0.0 February, 2005 Eustrongylides ignotus 8.3 6.7 R13.3 2.5 Trichinella spp. 5.0 0.0A 0.0 8.3 Capillaria pterophilli 10.8 R18.3 17.5 2.5 Camallanus cotti I1B.7 8.3 1.7 3.3 Y L T SI R IV E N U AN D B AI 52 Basil Ogamba Street: The highest drain-related prevalence of E. ignotus was observed in February, 2005 at 6.7%, that of Trichinella spp. was at 5.0% in October, 2004 and November, 2004. The highest drain related prevalence (18.3%) of C. pterophylli was observed in February, 2005 while the highest drain related prevalence of C. cotti at 6.7% was observed in October, 2004 (Table 4.3). Ahmadu Bello Road: The most prevalent nematode found in the drain related P. reticulata samples obtained from Ahmadu Bello Road was C. pterophylli at 17.5% and this was followed by E. ignotus at 13.3% also in February, 2005. However, the hRigheYst prevalent Trichinella spp. (8.3%) was observed in October, 2004, the most prAevalent C. pterophylli (12.5%) was observed in March, 2004 while the most prevalent C. cotti at Ahmadu Bello Road (11.7%) was observed in September, 2004 (Table 4.R3). Adenaike Alagbe Street : C. cotti was the most pre vLaleInt B nematode 18.3% found in P. reticulata obtained from this Street and this was during the month of September, 2004 with the most prevalent E. ignotus (16.7%) observed in P. reticulata obtained from Adenaike Alagbe Street in June, 2004 I(TTablYe 4.3). 4.4.4. Sex-related nematode parasite intensRity iSn P. reticulata: Total counts for each of the nEematode parasites observed in P. reticulata dissected during this study were recoVrded (Table 4.4). Parasite intensity was calculated according to the sex of P. reticulaIta host from which they were observed (Table 4.5). However, after parasite mean Nintensity data was subjected to ANOVA no statistically significant difference was Uobserved. A range of low mean intensity value of 0.3 ± 0.3 (mean intensity ± standa rd deviation) to the highest mean intensity at 5.0 ± 1.8 in male P. reticulata samApleNs were observed. In the case of female P. reticulata samples, the range was frDom as low as 0.3 ± 0.3 nematode parasite mean intensity to as high as 4.9 ± 1.8. BAI The highest topical monthly intensity in male P. reticulata samples was 9.0 and that was C. cotti in May, 2004 which was followed by the monthly intensity 5.5 for C. pterophylli in the same month (Table 4.5). E. ignotus: The highest sex-related E. ignotus intensity in male P. reticulata observed in the study was 3.0 in March, 2004 (Fig. 4.5) and that in female P. reticulata was 3.9 in September, 2004 (Table 4.5). Trichinella spp.: The highest sex-related intensity was 2.3 and it was observed in P. reticulata female in March and May, 2004 (Table 4.5). 53 Table 4.4. Total count of nematode parasites in Poecilia reticulata obtained from the wastewater drains of four selected streets in Lagos State Y RA R March, 2004 Eustrongylides ignotus 1 6 0 0 B4 9 7 0 Trichinella spp. 0 0 0 0 I 0 9 0 0 Capillaria pterophylli 0 0 0 L0 11 9 11 11 Camallanus cotti 0 0 Y0 0 8 0 0 0 A pril, 2004 Eustrongylides ignotus 0 I11T 0 0 0 0 0 0 Trichinella spp. S0 0 0 0 0 0 0 0 Capillaria pterophylli R0 0 0 0 0 0 0 0 Camallanus cotti 0 0 0 0 0 0 0 0 May, 2004 Eustrongylides ignotus 6 13 5 0 7 9 9 6 Trichinella spp. E 9 4 0 0 2 5 0 5 Capillaria pterIopVhylli 6 5 0 5 0 5 5 0 Camallanus cotti 0 7 0 0 0 0 9 3 J une, 2004 Eustr oUngyl Nides ignotus 0 0 0 0 6 8 26 5 Trichinella spp. 0 0 0 0 0 0 0 0 CNapillaria pterophylli 16 5 12 7 1 0 0 0 ACamallanus cotti 0 0 0 0 0 0 0 7 J uly, 2004 D Eustrongylides ignotus 0 0 0 0 0 0 0 0 Trichinella spp. 0 0 0 0 0 0 0 0 A Capillaria pterophylli 0 0 0 0 0 0 0 0 IB Camallanus cotti 0 0 0 0 0 0 0 0 August, 2004 Eustrongylides ignotus 0 0 0 0 0 0 0 0 Trichinella spp. 0 0 0 0 0 0 0 0 Capillaria pterophylli 0 0 11 6 8 0 0 3 Camallanus cotti 10 11 0 0 0 0 11 9 S eptember, 2004 Eustrongylides ignotus 9 6 0 10 0 6 8 9 Trichinella spp. 0 0 0 0 0 0 0 0 Capillaria pterophylli 5 5 0 0 0 0 8 6 Camallanus cotti 20 28 8 6 13 3 9 24 O ctober, 2004 Eustrongylides ignotus 6 6 5 0 0 0 9 9 54 Sex Street Name Male Igi-Olugbin Female Igi-Olugbin Male Basil Ogamba Female Basil Ogamba Male Ahmadu Bello Female Ahmadu Bello Male Adenaike Alagbe Female Adenaike Alagbe Trichinella spp. 0 0 9 0 4 8 5 8 Capillaria pterophylli 0 13 0 0 0 0 0 4 Camallanus cotti 10 8 8 5 5 0 5 9 November, 2004 Eustrongylides ignotus 0 0 0 0 0 0 1 1 Trichinella spp. 3 12 5 6 0 0 0 0 Capillaria pterophylli 4 3 0 0 8 0 0 0 Camallanus cotti 0 0 0 0 0 0 2 6 December, 2004 Eustrongylides ignotus 0 0 0 0 0 0 0 0 Trichinella spp. 0 0 0 0 0 0 0 0 Capillaria pterophylli 0 0 0 0 0 0 0 Y0 Camallanus cotti 0 0 0 0 0 0 0R 0 January, 2005 Eustrongylides ignotus 0 0 0 0 0 0 A0 0 Trichinella spp. 0 0 0 0 0 0 0 0 Capillaria pterophylli 0 0 0 0 0 R0 0 0 Camallanus cotti 0 0 0 L0 IB0 0 0 0 February, 2005 Eustrongylides ignotus 9 9 6 2 8 8 1 2 Trichinella spp. 4 5 0 0 0 0 5 5 Capillaria pterophylli 8 10 Y5 24 13 13 1 2 Camallanus cotti 0 I5T 6 8 0 2 0 4 S VE R UN I N DA A IB 55 Table 4.5. Monthly sex-related mean intensity of nematode parasites of Poecilia reticulata Month Sex Male Female March, 2004 Eustrongylides ignotus 3.0 1.3 Trichinella spp. 0.0 2.3 Capillaria pterophylli 2.2 1.4 Camallanus cotti 2.0 0.0 Y A pril, 2004 Eustrongylides ignotus 0.0 1.8 Trichinella spp. 0.0 0.0 R Capillaria pterophylli 0.0 0.0 A Camallanus cotti 0.0 0.0 R May, 2004 Eustrongylides ignotus 1.8 1.4 B Trichinella spp. 2.2 2.3 I Capillaria pterophylli 5.5 1.7 L Camallanus cotti 9.0 2.5 J une, 2004 Eustrongylides ignotus 2.5 1.Y3 Trichinella spp. 0.S0 I T0.0 Capillaria pterophylli 1.9 2.4 Camallanus cotti 0.0 3.5 J uly, 2004 Eustrongylides ignotuEs R0.0 0.0 Trichinella spp. 0.0 0.0 Capillaria pteropVhylli 0.0 0.0 CamallanuNs cotIti 0.0 0.0 A ugust, 2004 EustroUngylides ignotus 0.0 0.0 Trichinella spp. 0.0 0.0 CNapi llaria pterophylli 2.7 2.3 ACamallanus cotti 1.3 2.9 September, 2004 D Eustrongylides ignotus 1.9 3.9 A Trichinella spp. 0.0 0.0 B Capillaria pterophylli 1.4 1.8 I Camallanus cotti 1.6 1.8 O ctober, 2004 Eustrongylides ignotus 1.8 1.7 Trichinella spp. 1.4 2.0 Capillaria pterophylli 0.0 2.4 Camallanus cotti 4.0 1.7 November, 2004 Eustrongylides ignotus 1.0 1.0 Trichinella spp. 2.0 2.0 Capillaria pterophylli 3.0 3.0 Camallanus cotti 1.0 1.0 December, Eustrongylides ignotus 0.0 0.0 56 2004 Trichinella spp. 0.0 0.0 Capillaria pterophylli 0.0 0.0 Camallanus cotti 0.0 0.0 J anuary, 2005 Eustrongylides ignotus 0.0 0.0 Trichinella spp. 0.0 0.0 Capillaria pterophylli 0.0 0.0 Camallanus cotti 0.0 0.0 February, 2005 Eustrongylides ignotus 1.1 1.4 Trichinella spp. 1.0 1.4 Y Capillaria pterophylli 1.3 1.3 R Camallanus cotti 1.5 1.4 A LIB R ITY S R E IV U N N AD A IB 57 C. pterophylli: In the case of female P. reticulata, the most intense infection was 5.5 observed in May, 2004 (Table 4.5). C. cotti: The most intense C. cotti infection in female P. reticulata was 3.5 observed in June, 2004 samples (Table 4.5). 4.4.5. Drain-related nematode parasite intensity in P. reticulata: The drain-related intensity of nematode parasites in P. reticulata samples aggregated from the different drains without distinguishing their sexes were subjected to ANOVAY. It yielded ranges from a low mean intensity of 1.3 ± 1.3 to as high as 7.0 ± 3.0. R Monthly mean intensity differed significantly with drains (p < 0.05A). C. cotti had the highest drain related monthly intensity of 10.5 in the entire stuRdy and it was observed in Basil Ogamba Street in September, 2004 (Table 4. 6L). TIhi Bs was followed by C. cotti in October, 2004 at Igi-Olugbin Street and E. igYnotus in May, 2004 at Basil Ogamba Street at intensity of 6.0 each (Table 4.6).. In May 2004 and February, 2005, E. ignotuIs,T Trichinella spp., C. pterophylli and C. cotti were all found to have occurred in tShe P. reticulata obtained with not less than intensity of 1 from both Igi-Olugbin andR Adenaike Alagbe Streets (Table 4.6). VE I 4.5. Relative percentage paraNsite composition of infection 4.5.1. Sex-related relat ivUe monthly percentage composition (rmpc) of nematode parasite: The sex-sensNitive relative monthly percentage composition of nematode parasite (rmpc) illusDtrateAs gender-linked success of a nematode in dominance over other nematodAe parasites of P. reticulata at a given time. Sex-related prevalence of each neImBatode parasite of P. reticulata was related to each other in percentages for this purpose (Table 4.2). The relative monthly percentage parasite composition (rmpc) of E. ignotus and C. pterophylli were high in male and female P. reticulata samples obtained in March and June, 2004 on one hand, while a combination of C. pterophylli and C. cotti constituted the higher rmpc in August and September, 2004 on the other (Fig. 4.1). In August, 2004, a combination of C. pterophylli and C. cotti were the only two nematode parasites of male P. reticulata. 58 Table 4.6. Monthly drain-related mean intensity of nematode parasites of Poecilia reticulata on drain locations irrespective of sex of Host AR Y Month Nematode RMarch, 2004 Eustrongylides ignotus 1.0 0.0 1.9 3.5 Trichinella spp. IB0.0 0.0 2.3 0.0 Capillaria pterophylli L 0.0 0.0 1.3 2.4 Camallanus cotti 0.0 0.0 2.0 0.0 A pril, 2004 Eustrongylides ignotus Y 1.8 0.0 0.0 0.0 Trichinella spp. T 0.0 0.0 0.0 0.0 Capillaria pteropShyllIi 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 0.0 May, 2004 EustrongEylideRs ignotus 1.4 6.0 2.3 1.3 Trichinella spp. 2.2 0.0 2.3 2.5 CapIilVlaria pterophylli 1.8 0.0 1.7 5.0 NCamallanus cotti 3.5 0.0 0.0 4.0 J une, 2004 Eustrongylides ignotus 0.0 0.0 4.7 1.6 U Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophylli 1.9 1.6 1.0 0.0 N Camallanus cotti 0.0 0.0 0.0 3.5 J uly, 2004 A Eustrongylides ignotus 0.0 0.0 0.0 0.0 D Trichinella spp. 0.0 0.0 0.0 0.0 A Capillaria pterophylli 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 0.0 I ABugust, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 3.2 2.7 1.5 Camallanus cotti 2.1 0.0 0.0 1.5 September, 2004 Eustrongylides ignotus 2.5 0.0 3.0 2.1 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophylli 1.0 0.0 0.0 2.8 Camallanus cotti 1.7 10.5 1.1 1.5 O ctober, 2004 Eustrongylides ignotus 3.0 1.0 0.0 1.6 Trichinella spp. 0.0 2.2 1.2 2.6 59 Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Capillaria pterophylli 2.2 0.0 0.0 4.0 Camallanus cotti 6.0 1.6 5.0 1.8 November, 2004 Eustrongylides ignotus 0.0 0.0 0.0 1.0 Trichinella spp. 1.9 1.0 0.0 0.0 Capillaria pterophylli 3.5 0.0 2.7 0.0 Camallanus cotti 0.0 0.0 0.0 1.0 D ecember, 2004 Eustrongylides ignotus 0.0 0.0 0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 0.0 0.0 0.0 Camallanus cotti 0.0 0.0 0.0 Y0.0 January, 2005 Eustrongylides ignotus 0.0 0A.0 R0.0 0.0 Trichinella spp. 0.0 0.0 0.0 0.0 Capillaria pterophylli 0.0 0.0 0.0 0.0 Camallanus cotti IB0.0 R0.0 0.0 0.0 F ebruary, 2005 Eustrongylides ignotus 1.8 1.8 1.0 1.0 Trichinella spp. 1.5 0.0 0.0 1.0 LCapillaria pterophylli 1.4 0.8 1.2 1.0 Camallanus cotti TY 2.5 0.6 1.0 1.0 SI R IV E N U N A D B AI 60 C. pterophylli had rmpc of 30.2% while C. cotti dominated with an rmpc of 68.8% in male P. reticulata. In the case of female P. reticulata, C. pterophylli had rmpc of 37.0% while C. cotti dominated with an rmpc of 70.0% in the same month of August, 2004 (Fig. 4.9). The parasite E. ignotus had rmpc of 100% in April, 2004; 50.9% in May, 2004 and 59.2% in June 2004 in female P. reticulata while the rmpc of E. ignotus in male P. reticulata were 65.6% in May, 2004; 50.0% in June, 2004 and 39.2% in February, 200Y5 (Fig. 4.9). R For the female samples of P. reticulata, Trichinella spp. had the Afollowing rmpc: 41.9% in October, 2004 and 37.0% in November, 2004 in contBrastR with the rmpc of 22.2% in October, 2004 and 53.5% in November, 2004 obIserved in male P. reticulata (Fig. 4.9). L The highest rmpc for C. pterophylli in male P. reYticulata samples were 55.3% observed in March, 2004 followed by 50.0% in JunIeT, 2004; 30.2% in August, 2004; 37.0% in November, 2004 and 39.2% in FebruarSy, 2005 though in female P. reticulata it was 31.7% in March, 2004; 23.3% in MRay, 2004; 29.6% in June, 2004; 37.0% in August, 2004; 40.9% in November, 2004E and 51.3% in February, 2005 (Fig. 4.9). The nematode parasite C. cotNti wIas V observed in P. reticulata with the highest rmpc maxima of 71.0% in femUale P. reticulata samples obtained in September, 2004 but 69.8% in male P. reticu lata dissected in August, 2004. It was similarly observed to have had rmpc of 63N.0% in female P. reticulata samples obtained in August, 2004 and 63.75% in male AP. reticulata samples obtained in September, 2004 (Fig. 4.9). D 4.5.2. DArain-related relative monthly percentage composition of nematode parasite prIevBalence: The nematode parasites E. ignotus, C. pterophylli and C. cotti constituted major parasites recovered in their hosts in August and September, 2004 as well as in February, 2005 (Fig. 4.10). E. ignotus had 100% rmpc in P. reticulata obtained from Igi-Olugbin Street in March and April, 2004 while Trichinella spp. had 100% rmpc in P. reticulata obtained from Basil Ogamba Street in November, 2004 without prejudice to the sex of the fish hosts (Fig. 4.10). 61 RY 100% 90% BR A 80% I 70% L 60% Y 50% 40% IT 30% RS20% 10% 0% VEI March, April, 2004 May, 2004 June, 200U4 JulNy, 2004 August, September, October, November, December, January, February,2004 2004 2004 2004 2004 2004 2005 2005Month EustrongylidesN ignotus Trichinella spp. Capillaria pterophilli Camallanus cotti Figure 4.9.Sex-related Relative monthly perAcentage composition (rmpc) of nematode parasite prevalence in P. reticulata examined. AD 62 IB Relative monthly percentage composition(%) Female Male Female Male Female Male Female Male Female Male Female Male Female Male Female Male Female Male Female Male Female Male Female Male Y 100% AR 90% 80% R 70% 60% IB 50% L 40% 30% 20% TY10% 0% SIR IV E March, April, 2004 May, 2004 June, 2004 JulyN, 2004 August, September, October, November, December, January, February,2004 2004 2004 2004 2004 2004 2005 2005 Month Eustrongylides ignotu N sUTrichinella spp. Capillaria pterophilli Camallanus cotti Figure 4.10. Drain-related Relative monthlyA percentage composition (rmpc) of nematode parasite prevalence in P. reticulata examined. BA D 63 I Relative monthly percentage composition Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street Similarly, only C. cotti was prevalent in all the P. reticulata samples obtained from Igi- Olugbin Street in August, 2004. The exclusive prevalence of 100% rmpc for C. pterophylli occurred at Basil Ogamba Street and Ahmadu Bello Road in August, 2004 (Fig. 4.10). 4.6. Mean physicochemical parameters There was no significant difference in the mean monthly pH and DO of wastewater obtained from all the four selected Streets in Lagos State. However, thRere Y were significant differences in the wastewater temperature, transparency and drain depth during the course of this study (p < 0.05). Mean monthly phRysicAochemical parameters of wastewater are on Table 4.7. IB 4.6.1. Mean monthly physicochemical parameters L Temperature: The highest mean monthly wastewatYer temperature was observed in July, 2004 at 26.75 ± 0.79 ºC while the lowest meaInT monthly temperature of 23.69 ± 0.80 ºC was observed in January, 2005. S pH: Though, the lowest mean monthRly pH of 6.85± 0.92 was obtained in May, 2004 the highest mean monthly pH oVf 7.6E6 ± 0.77 was observed in August, 2004. -1DO: The high mean monthlIy DO of 10.33 ± 1.52mgl was observed in October, -1 2004 while the lowest mean mNonthly DO of 6.43 ± 1.18mgl was observed in March, 2004. U Transparency: H owever, the lowest mean monthly transparency of 12.10 ± 7.46cm was obsAerveNd in July, 2004 when the highest mean monthly transparency of 14.93 ± 11.8D5cm was observed in January, 2005. DArain Depth: Though the highest mean monthly drain depth of 13.33 ±2.34cm was Bobserved October, 2004, the lowest mean monthly drain depth of 8.55 ± 4.78cm waIs observed in March, 2004. 4.6.2. Mean physicochemical parameters in drains. There were significant differences in the temperature, transparency and drain depth of wastewater samples collected from each of the selected drains (p < 0.05). However, no significant differences were observed in the DO and pH recorded from the wastewater samples from the drain. 64 Y Table 4.7. Means of Monthly Physicochemical Parameters Measurement in the Selected Drains Throughout the Experiment R Streets Igi-Olugbin Street Basil Ogamba Street Ahmadu Bello Road Adenaike Alagbe Street A Sampling Months R LI B Y March, 26.5 7.2 8 25 6 24.5 7 6 3 5.2 26.5 6.5 I6.5T 15.2 15.6 25.5 7 5.2 8.2 7.5 2004 April, 2004 25.0 7.0 7.6 24.6 7.4 26.3 6.9 7.5 4.5 13.4 26.8 7.S4 6.3 15.2 18.8 25.0 6.8 8.2 8.2 8.5 May, 2004 25.5 6.2 5.0 22.5 8.4 25.5 7.9 7.5 3.0 6.5 25.0 7.4 7.0 17.9 20.1 26.5 6.0 8.3 8.2 9.5 June, 2004 25.0 6.2 8.2 21.8 11.4 27.5 8.1 8.1 4.0 11.0 25.0 8.2 8.1 14.8 18.8 26.8 6.0 6.2 8.0 11.6 July, 2004 25.8 7.8 6.0 20.8 7.4 26.5 7.7 8.4 4.0 13.2E 27R.5 6.2 8.0 15.5 16.7 27.3 7.0 6.2 8.2 9.3 August, 25.5 8.6 8.1 20.3 6.8 27.0 7.4 8.2 2.5 16.8 25.8 8.0 8.1 24.7 15.3 27.5 6.8 5.0 8.3 10.3 2004 September, 25.8 8.6 8.8 20.1 12.8 26.3 7.1 9.7 2I.5 V16.9 26.3 7.0 10.8 22.4 13.9 26.5 8.0 6.3 7.9 9.2 2004 October, 25.8 8.3 10.8 19.7 11.5 27.0 7.6 8.N1 3.0 16.6 25.0 7.4 10.9 18.4 13.6 27.3 7.4 11.6 8.1 11.7 2004 November, 24.5 7.0 10.2 19.8 11.8 25.3 7.U1 9.9 4.5 16.6 24.3 7.8 9.2 21.2 11.3 25.3 7.0 10.6 8.3 11.2 2004 December, 24.0 6.8 11.0 22.4 10.6 24.3 7.1 10.1 4.5 16.0 24.0 7.1 7.3 19.9 11.3 25.3 7.1 8.0 8.7 11.2 2004 January, 22.5 6.7 9.5 28.5 10.5 2N4.0 7.1 7.1 2.5 16.0 24.3 7.2 8.3 16.6 11.5 24.0 7.0 7.9 8.7 11.2 2005 February, 24.3 7.4 8.1 30.8 10.6 23.0 7.1 6.1 3.5 17.0 24.0 7.1 8.8 16.5 11.5 24.8 7.0 9.9 9.0 11.0 2005 DA A 65 IB O Temperature ( C) PH Dissolved Oxygen (mg/l) Transparency (cm) Drain Depth (cm) O Temperature ( C) PH Dissolved Oxygen (mg/l) Transparency (cm) Drain Depth (cm) O Temperature ( C) PH Dissolved Oxygen (mg/l) Transparency (cm) Drain Depth (cm) O Temperature ( C) PH Dissolved Oxygen (mg/l) Transparency (cm) Drain Depth (cm) Temperature: The highest mean temperature of 25.96 ± 1.14ºC was observed at Adenaike Alagbe Street while the lowest, 25.00 ± 1.06 ºC was observed at Igi-Olugbin Street. pH: The highest mean pH of 7.32 ± 0.38 was observed at Basil Ogamba Street, with the lowest observed 6.90 ± 0.54 observed at Adenaike Alagbe Street. -1 DO: The highest mean DO of 8.43 ± 1.79 mgl observed at Igi-Olugbin Street contrasts with that of the mean temperature while the lowest mean DO was obtained at 7.75 ± -1 2.11mgl was observed from Adenaike Alagbe Street. Y Drain Depth: Meanwhile, the highest mean drain depth of 14.84 ± 3.21cmR was observed at Ahmadu Bello Road with the lowest mean drain depth of 9.6R0 ± A2.27cm at Igi-Olugbin Street. IB 4.7. Correlation Co-efficient of physicochemical paramYete rs L with prevalence and intensity 4.7.1. Correlation Co-efficient of physicochemicIaTl parameters with nematode parasite prevalence in P. reticulata: S The monthly prevalence of C. pteropRhylli positively correlated at 0.6 with the drain depth of Igi-Olugbin Street whiVle CE. cotti correlated at 0.7 with pH (Appendix 3). The monthly prevalence of C. pterIophylli moderately but positively correlated with the temperature at 0.5 and pH ofN wastewater at 0.6 in Basil Ogamba Street. However, monthly prevalence of E . iUgnotus highly correlated at 0.9 with those of Trichinella spp. and C. cotti each (Appendix 4). At AhmaAdu BNello Road, monthly prevalence of C. pterophylli correlated at 0.7 with that of DE. ignotus (Appendix 5). AAt Adenaike Alagbe, wastewater transparency and monthly prevalence of C. pterBophylli negatively correlated at -0.6 with that of the wastewater temperature while E. Iignotus correlated at 0.6 with drain depth though Trichinella spp. highly correlated with DO at 0.8 (Appendix 6). 4.7.2. Correlation Co-efficient of physicochemical parameters with nematode parasite intensity in P. reticulata: The intensity of C. pterophylli correlated at 0.6 each with Drain depth and the intensity of Trichinella spp. while it correlated with the intensity of E. ignotus at 0.7 at Igi-Olugbin Street (Appendix 7). 66 The correlation coefficient between the temperature and pH of wastewater in Basil Ogamba Street was moderately at 0.6 (Appendix 8) while there was no correlation between the nematode mean intensity and physicochemical parameters of wastewater. In the case of Ahmadu Bello Road, temperature correlated with Drain Depth at 0.6 with no correlation between mean intensity of any of the nematode parasites obtained from P. reticulata (Appendix 9). At Adenaike Alagbe Street, the intensity of C. cotti negatively correlated wiYth pH at -0.6 while C. pterophylli correlated with Trichinella spp. at 0.8 (AppendAix 1R0). R LI B ITY RS IV E N U AN AD IB 67 CHAPTER FIVE DISCUSSION Nematode parasite prevalence in P. reticulata obtained from the four selected Streets of Lagos State was neither sex-dependent nor drain-dependent. The nematodes E. ignotus, Trichinella spp., C. pterophylli and C. cotti encountered in this study are not currently amongst established DNOs and OSDs within the definition of the OIE. Therefore, evidence from this study suggests that P. reticulata from Igi-Olugbin, BasYil Ogamba, Adenaike Alagbe Streets and Ahmadu Bello Road would safely qualRify as restriction-proof commercial ornamental fish for culture and domestic displAay as well as for export since only viral fish infections presently constitIute D RNOs by OIE definitions. B Although, according to the OIE fifth Strategic Actio n LPlan (OIE, 2009), the identification, prevention and management control of epYizootics and zoonoses helps mankind throughout time, the overall prevalence IofT 3.6%, 3.5% and 3.4% for E. ignotus, C. pterophylli and C. cotti in P. reticulaSta probably reflects the susceptibility of P. reticulata samples to nematode parRasite transmission through feeding habit preferences, life cycle dynamics aVnd Eenvironmental synchrony between host and parasite types (Anderson and MaIy, 1979; Anderson and May, 1985 and Anderson, 1988). N The above levels oUf overall prevalence do not infer inherent carriage of these nematode parasites wNhen compared to the relatively higher prevalence of some of the same nematode Aparasites observed in P. reticulata or other Poeciliids obtained from homestead aDquaria (Kim et al., 2002) and natural drains from other regions of the world. IAn addition, the prevalence of these four nematode species do not reflect an intIraBctable association between the P. reticulata obtained from the selected Streets of Lagos and the nematodes encountered in this study. Though C. pterophylli had the highest sex-related prevalence of 15.8% prevalence in female P. reticulata samples obtained in February, 2005 (Table 4.2), it was C. cotti that had the highest sex-related nematode prevalence of 13.3% in male P. reticulata in September, 2004 (Table 4.2). Despite the fact that there was no statistical significance in sex-related differences in nematode prevalence in P. reticulata, the pertinent issue is, could one fail to notice that C. cotti also held the reputation as the 68 99nematode with the highest drain-related prevalence at 23.3% observed in P. reticulata obtained in September, 2004 from wastewater drains at Igi-Olugbin Street (Table 4.3 which was by record the all-time maxima in this study? One explanation for the persistence and prominence of C. cotti as a very prevalent nematode parasite of P. reticulata in this wastewater drains could be its adaptation to hibernation in the absence of a suitable intermediate host and its by-pass of the latter in re-infection of new hosts once wastewater renewal occurs between rain seasons. Certainly, E. ignotus had the highest sex-related monthly intensity of 3.9 Yin female P. reticulata observed in September, 2004 (Table. 4.5). However, as reRgards mean intensity of nematode parasites in male P. reticulata, C. cotti still had tAhe highest sex-related monthly intensity of 9.0 observed in May, 2004 (Table.I 4.5) a Rnd the highest drain related monthly intensity of 10.5 in the entire study whi chL was B observed at Basil Ogamba Street in September, 2004 (Table. 4.6). If it haYd been entirely co-incidental that C. cotti which had the highest sex-related prevalenTce in male P. reticulata and also had the highest drain-related prevalence in P. reticulaIta, the reputation of this nematode as the parasite with the highest sex-related andS drain-related monthly intensity in P. reticulata should draw appreciable attention Rto it. All this notwithstanding, the hiEghest monthly prevalence of C. cotti in P. reticulata obtained from both seIx-Vrelated and drain-related segment of this study compares markedly far less thNan the 51% prevalence of C. cotti reported by Moravec and Justine (2006) in the gUobiid, Awouis guamensis, obtained from the La Foa river of New Caledonia andN the 71% of C. cotti in P. reticulata obtained from export ready stock in South KAorea and Indonesia by Kim et al., 2002. Notably though, the monthly mean intensDity of 10.5 in P. reticulata of this present study is more than that of 5 reportedA in the gobiid by Moravec and Justine (2006). IBOn record, the first reported case of C. cotti infection of any fish host was in 1927 by Fujita, the next known report of this nematode infecting an ornamental fish species, such as P. reticulata, in Korea and Indonesia was by Kim et al. (2002). The current study would represent the first known investigation of the prevalence and intensity of nematode parasites of feral P. reticulata in Nigeria. In addition, although the prevalence study of C. cotti in P. reticulata by Kim et al., 2002 was not sex-related as in the current instance, the sample size of P. reticulata hosts in Kim et al., 2002 may have been too small to reflect a proper demographic illustration of C. cotti prevalence 69 in P. reticulata feral populations. Meanwhile, C. cotti is now gaining attention as a cosmopolitan nematode parasite of ornamental fish species with the uncommon advantage of monoxeny that facilitates dormancy in the face of intermediate host bottleneck by directly infecting other susceptible fish hosts within immediate reach (Levsen and Jakobsen, 2002). Except for the study at export-ready holding farms, where Thilakaratne et al. (2003) found a 0.7% prevalence of Capillaria spp. in P. reticulata in their study of parasitic infections in freshwater ornamental fishes in Sri Lanka, no other publisheYd record of the prevalence or mean intensity of C. pterophylli in P. reticulata hadR been encountered. The low prevalence in Thilakaratne et al. (2003) could be as Aa result of screening and removal of moribund samples of P. reticulata and thIeB ext Rra effort made to preclude diseased samples from the quarantine farm unlike iLn the case of this study where feral stocks were examined for nematode parasites. Relative percentage monthly composition (rmpc) rYeflects the domination of one nematode parasite encounters in P. reticulata in tIhTis study by another. Therefore, instances where a particular nematode is found Sto have exclusively retained a 100% rmpc could infer a suitable host physiologicRal or wastewater physicochemical milieu enhancing that given nematode parasiteE establishment as reflected in prevalence or endemy as measured in intensity. AIsV a result, one should not fail to note such instances of a 100% in drain-related rmpNc analyses of this study. Only in one instance was a sex- related 100% rmpc obse rvUed. And this was in the case of E. ignotus in P. reticulata females in April, 2004 (Fig. 4.1). There weAre hNowever many cases of drain-related 100%rmpc in this study such as that of E.D ignotus in March and April, 2004 at Igi-Olugbin Street; Trichinella spp. in NovembAer, 2004 at Basil Ogamba Street; C. pterophylli in June at Igi-Olugbin and BaIsiBl Ogamba Street as well as in November, 2004 at Ahmadu Bello Road and C. cotti in August, 2004 at Igi-Olugbin Street (Fig. 4.2). Other notable rmpc were E. ignotus at 92%rmpc in June, 2004at Adenaike Alagbe Street, Trichinella spp. at 92% in October, 2004 at Ahmadu Bello Road and November, 2004 at Igi-Olugbin Street while C. pterophylli had 82%rmpc in March, 2004 (Fig. 4.2). This notwithstanding, conscious avoidance of collecting female P. reticulata from the wastewater drains in April when they were found to have E. ignotus of 100% rmpc and male P. reticulata in May with E. ignotus of 65% rmpc is advised. Collection of P. reticulata from the wastewater 70 drains may also be unprofitable in August and September because those in this study indicated a 73% and 69% rmpc for C. cotti in female and male P. reticulata, respectively. High rmpc may symptomize possible intervention of new intermediate or paratenic hosts for the concerned parasites out-competing other nematodes in the identified wastewater drains. It may also be as a result and effect of particular anthropogenic activities and habits of people living around those areas that impact the abutting wastewater drains. All these notwithstanding, it would be naïve not to takYe notice of the fact that the rudiments of sexual characters of the adult E.ignotus Rwhich should clearly be completed in their final hosts, piscivorous wading birdsR, hadA started to form in the fourth stage larvae of E. ignotus (Fig. 4.8 and Fig. 4.9) even when P. reticulata is not the final host. IB Apart from the twin effect of globalization and climate cLhange, rapid unplanned urbanization resulting in increasing population growthY at Igi-Olugbin and Basil Ogamba Streets within the more densely populatedI sTectors of Lagos State (National Population Commission of Nigeria, 2006 and CuSrry, 2009) lead to poor sanitation and uncontrolled roaming of household pets suRch as cats, dogs and occasional visits of rodents, poultry and ducklings to theVse dErains. The carrions of these animals were often encountered on some occasions parIticularly in wastewater drains of these Streets during fish sample collection. While tNhe existence of Cyclopod copepods in the drains would not seem strange, the po sUsibility of P. reticulata feasting on these dead avian, feline pets and rodents couNld lead to transfer of encysted Trichinella spp. across previously known species bAarriers to P. reticulata. TherDe was no significant difference in mean monthly pH and DO across all the four draAins sampled in this study. And this is not surprising since photic adaptations of waIstBewater phytoplanktons that modify pH and DO through diurnal photosynthesis is known to occur in the daytime when water physicochemical parameters in this study were measured. However, foraging activities of P. reticulata, egg-laying mosquitoes, their larvae and occasional visitors to the wastewater in drains may continually influence daily temperature, transparency and drain depth and ultimately their mean monthly values that were found to have been significantly different across drains. The high correlation observed at Adenaike Alagbe drains between the prevalence of Trichinella species and wastewater DO, between prevalence of C. pterophylli and 71 wastewater temperature and also between the mean intensities of C. pterophylli and Trichinella spp. in P. reticulata may be related to ones daily encounter with animal ritual sacrifices at some of the walkways near sectors of the wastewater drains that may have lead to recrudescent slouch of infected animal carrion into wastewater during episodic rains. Indeed, two different shrines for African traditional worship exist at the ends of Adenaike Alagbe Street in Ikorodu LGA of Lagos State. On the other hand, it is interesting to note that while the highest mean -1 wastewater DO of 8.43 ± 1.79mgL and transparency of 23.02 ± 3.60 cm weYre observed at Igi-Olugbin Street wastewater that same Street had the lowest Rmean temperature of 25.00 ± 1.06 ºC and drain depth of 9.60 ± 2.27cm. AAlthough, wastewater temperature and transparency moderately correlated negaRtively at -0.5 (Appendix 3) to buttress the highest mean transparency and lowest ImBean temperature at Igi-Olugbin Street above, the moderate negative correlation be twLeen E. ignotus and DO at -0.5 coefficient finds relevant support from the observatYions of Coyner et al. (2003). They indicated that anthropogenically altered wasteIwTater sites in Florida, USA that were comparable to those of Igi-Olugbin Street iSn Lagos State, Nigeria where monthly environmental sanitation exercises occur, areR characterized by higher mean densities of piscifaunal and oligochaete hosts of E. igEnotus accompanied by decreased surface water DO but increased total phosphoruIs,V nitrogen, chlorophyll-a, emergent vegetation and grasses. So also is the observNation in this study that prevalence of E. ignotus in P. reticulata was not sex-re lUated comparable to the conclusions of Coyner et al. (2003) that the ratio of infNected male and female Gambusia holbrooki, another wastewater piscifaunal, by EA. ignotus did not differ significantly. At BDasil Ogamba Street, where the highest mean wastewater pH at 7.32 ± 0.38 and the Alowest mean wastewater transparency at 3.46 ± 0.81cm was observed , the preIvBalence of C. cotti and Trichinella spp. were found to be very highly correlated at 1.0 though the prevalence of E. ignotus correlated with those of Trichinella spp. and C. pterophylli at 0.9. Similarly, C. pterophylli was also found to have moderately correlated with temperature at 0.6 and with pH at 0.5 (Appendix 4) indicating that the prevalence of this nematode somehow optimized in its P. reticulata host with increasing wastewater temperature and pH. However, the near perfect inter-nematode parasite prevalence correlated at high mean pH and very low mean wastewater 72 transparency at Basil Ogamba Street suggests a wastewater nematode faunal utopia where fair-play access to nutrient, intermediate hosts and final hosts equilibrium exists. The moderately high correlation between the prevalence of C. pterophylli and E. ignotus at 0.7 on Ahmadu Bello Road where the highest mean drain depth at 14.84 ± 3.21cm (Appendix 5) was recorded may reflect the confluence between nematode parasite availability and the benthophagous habit of P. reticulata in highly debriated wastewater drains where contact between benthophagous hosts and nematode parasites intermediate hosts such as Oligochaetes are far better assured. This interplay of meaYn temperature, transparency and drain depth is also reflected in the moderate correRlation between prevalence of C. pterophylli and mean transparency at 0.5 on one haAnd and the correlation of prevalence of E. ignotus and mean drain depth at 0.6 at AdRenaike Alagbe Street where the highest mean temperature at 25.94 ± 1.14 ºC but IthBe lowest mean pH at 6.90 ± 0.54 and DO at 7.75 ± 2.11 mgl-1 were observed Y(Ap p Lendix 6). Even if wastewater mean pH and DO were fouTnd to have not been significantly different in the whole study, the negative correlationIs between mean transparency and mean temperature at -0.6 on Adenaike Alagbe StSreet in one instance, and prevalence of C. pterophylli and mean temperature at -0R.6 (Appendix 6) on the other, makes the coupling effect of water chemistryV onE the transmission of C. pterophylli within wastewater piscifauna become obIvious. This would mean that Trichurid nematodes such as C. pterophylli reputed Nto be capable of transmitting infection from one aquatic vertebrate host to anothe r Uby side-stepping the need for intermediate hosts (Moravec et al., 1987) could survive the impact of climate change more resiliently than other nematodes. The anoNmalous property of water that does not accommodate too wide mean tempeDraturAe ranges and turbidity or low transparency of flooded wastewater that are oftenA readily resolved into eutrophication during succeeding high nutrient load that folIloBw floods may not deter the transmission of C. pterophylli during outfalls of natural disasters. In the correlation of nematode parasite mean intensity with physicochemical parameters, the mean intensities of C. pterophylli correlated with that of Trichinella spp. at 0.7 just as the mean intensity of C. cotti correlated with that of E. ignotus also at 0.7 on Igi-Olugbin Street (Appendix 7). It is safe to infer that similar water quality with direct or indirect regards to water chemistry predispose P. reticulata to enhanced intensification of infection by all these four nematodes found at Igi-Olugbin Street. It 73 was also observed that the mean intensities of C. pterophylli correlated with that of Trichinella spp. at 0.8 on Adenaike Alagbe Street (Appendix 10) though the mean intensity of C. cotti correlated with that of Trichinella spp. and that of C. pterophylli at 0.5 each, respectively on P. reticulata obtained from Adenaike Alagbe Street. It is noteworthy, however, that a general pattern of moderate correlation between drain depth and DO was observed at 0.6 on Igi-Olugbin Street (Appendix 7), at 0.5 on Basil Ogamba Street (Appendix 8) and Adenaike Alagbe Street (Appendix 10). The only negative correlation with regards to nematode parasite mean intensity between draYin depth and DO was observed at -0.5 on Ahmadu Bello Road (Appendix 9). R Nonetheless, drain-dependence in nematode parasite mean intensity cAorrelating with wastewater chemistry in this study indicates the possibility Iof oth Rer underlying water quality factors apart from host sex that could have p reLdispo Bsed obtained fish samples to spontaneity in nematode parasite visibilityY and multiplication at the particular months of heightened intensity of E. ignotus,T C. cotti and C. pterophylli. As a result, it is necessary to underline the fact that sincIe mean temperature, transparency and drain depth were found to be statistically siSgnificant in this study, the months of March, 2004 when the lowest mean drain deRpth was observed at 8.55 ± 4.78cm; July, 2004 when the highest mean temVperEature of 26.75 ± 0.79 ºC but the lowest transparency of 12.10 ± 7.46cm wIas observed; and January, 2005 when the lowest mean temperature at 23.69 ± 0N.80 ºC but the highest mean transparency was observed at 14.93 ± 11.85cm deserUve epizootiological notice and enquiry. It would not be too presumptive to therefore flag the months of January, March and July as indicative of critical nematode-intNense P. reticulata collection months particularly at Ahmadu Bello Road and ADdenaAike Alagbe Street where substantial correlations amongst wastewater mean temAperature, transparency and drain depth have been noted. IBIt is noteworthy that the focus of previously reported nematode parasite prevalence and intensity in ornamental fish species had been limited to the end-point of the OFI value chain (Ponpornpisit et al., 2005). For this reason, only prevalence of most nematode parasites in homestead aquaria, retail points and directed aquaculture systems of ornamental fish in developed economies of the world have enjoyed sustained studies. With the growing exceptions of newly directed attention on OFI in neo-tropical and sub-tropical regions of the World such as Trinidad and Tobago, the Amazon region (Chao, 1992; 1993; Chao and Prang, 1997; Chao, 2001), New 74 Zealand, Australia where conservation concerns of Reef damage due to deplorable harvest of ornamental fish from the wild occur (Chan and Sadovy, 2000; Claydon, 2005) and, the often well reported Asian continent’s experience in aquaria business (Chou et al., 2002), nematode parasite impact on the OFI in Africa has been clearly and largely underreported. P. reticulata was unofficially introduced into Lagos wastewater drains as a biological control measure against mosquitoes breeding in such drains by European officials of the colonial government of Nigeria as the earliest records in the 1970Ys shows (Welcomme, 1988). Malaria was the major scourge of European coloAnial Rlife in the West Africa and Asia of twentieth century (Manna et al., 2008). Even if official sanction of the introduction of this fish into Nigeria as pet may notI oBffici Rally exist, just as they are wont elsewhere, it is all the same necessary to draw a new risk map for invasive alien fish species in Nigeria. One may disagYree w Lith any of the above mentioned routes as the means of introduction of P. reticulata into Nigeria. What is not in doubt is the ready availability of P. reticulata in ImTany wastewater drains of Lagos State (Anogwih and Makanjuola, 2010; Lawal Sand Samuel, 2010). P. reticulata still retains its elegant colour and aggressive naRture whether in drains or aquarium tanks qualifying it as an ornamental fish specieEs though the standing nematode parasite fauna may have immigrated with theI Vhost in the original translocation into Lagos wastewaters. Other studies havNe shown that many alien invasions follow the pattern of transportation, escape or iUntentional introduction before full aggressive establishment and spread to exert propa gule pressure on an ecosystem (Courtenay and Stauffer, 1990; Courtenay and MAoylNe, 1996; Dugan, et al., 2006). AlthDough body and fin colour, caudal fin shapes and size of P. reticulata account Afor contemporary grading and sorting of samples at the downstream of the OFI, disIeBase susceptibility, carriage at swimming and other features that help in export product qualification in the OFI are health related (Zion et al., 2008). For this reason, it is difficult to ignore all the fine points predisposing to potential disease state as well as identify measures for ensuring upstream product quality assurance as in the case of P. reticulata that is in universal demand (Courtenay, 1999). However, drain-dependence in nematode parasite mean intensity in this study may indicate that another underlying factor apart from host sex could be predisposing obtained fish samples to spontaneity in nematode parasite visibility and multiplication 75 at the particular months of heightened intensity of E. ignotus, C. cotti and C. pterophylli. Shed E. ignotus eggs are ingested by primary benthophagous hosts such as Chironomids and Oligochaetes (Frederick et al., 1996) that are eaten by several intermediate hosts such as P. reticulata and other Poeciliids while larger piscivorous fishes serving as paratenic hosts facilitate their development to third stage larva. Fourth stage larvae are ingested by Ciconiiforms such as White Egrets, final hosts of E. ignotus, when they prey on these fishes where E. ignotus finally develops into mature adults (Measures, 1987; 1988; Spalding et al., 1993; Frederick and McGhee, 19R94). YIt would appear that the observation of these water wading birds within the drains in Lagos completed the infection cycle of E. ignotus in P. reticulata in this studyA. Frederick et al., 1996 noticed a decline in E. ignotus prevalenRce from 39% observed in G. affinis’ in the Northern Florida quartz-like dra B iLns (IBrown et al., 1990) to 10% prevalence in the G. affinis samples obtained fromY the thick peats of Southern parts of the same Florida peninsular. His explanation tThat altered soil conditions in the Southern parts may make sinking E. ignotus eggs inaIccessible to Oligochaetes that are intermediate hosts to, and foragers of, E. ignotSus eggs becomes plausible. Constant disturbance of soil types through recurrent Rexcavations lead to the exposure of clay, sandy and lime overlays to bring parasiteE eggs to the water/soil interphase that had been otherwise lost to intermediate hostIs Vto the surface for ingestion by bacteriophylic and detritivorous Oligochaetes. ThNe 1.5% prevalence of Trichinella spp. represents the first such record in P. reticuUlata. Though the prevalence is low, further studies in confirming the exactN spe cies of Trichinella cyst in the muscle of P. reticulata would be necessary (BruscAhi and Murrell, 2002). It may have originated from the close nocturnal interaction oDf house rodent carriers such as domestic rats, Rattus rattus, domestic cats and dogAs that frequent wastewater drains at night that drink and defecate into these draIinBs. It is normal to expect that since terrestrial and aquatic scavengers feed on carcasses of dead organic living matter, the known persistence of Trichinella spp. larvae in carcasses (Kim, 1983) would ensure transmission of Trichinosis in man and other animals once the cyclozoonotic loop of carnivore and scavenger is complete. Similarly, omnivorous fish species such as Poecilia reticulata and Clarias gariepinus that scavenge on dead organic matter and carcasses or cannibalize moribund individuals of their species of other fish species have the potential of becoming paratenic hosts to infective Trichinella spiralis larvae. AdelNabih et al (2003) reported 76 experimental infection of C. gariepinus with T. spiralis larva which though failed to encyst in the muscles of infected catfishes, yet the larvae persisted in the intestine of these catfish and when the latter were fed to albino rats 48 hours after experimental infection of fish, viable T. spiralis larvae were found in the rats. Indicative biochemical response with regards to aspartate aminotransferase and alanine aminotransferase changes associated with liver and muscle tissue damages following Trichinosis have been noted in the experimental infection of catfishes. This gives credence to C. gariepinus as a potential paratenic hosts to Trichinella spp. and this may explain thYe infection of P. reticulata by Trichinella spp. What is however further surprising Rin the case of Trichinella spp. is the susceptibility and successful experimental inAfection of both carnivorous and herbivorous animals pigs, monkeys, sheep, cattleR, horse young chickens, pigeons, magpies and rooks (Cram, 1941), horses (AdIelB et al., 2003) and rabbits (Yacoub et al., 1993) by this parasite. CampbeYll ( 19 L83) and MacLeane et al.(1989) reported that marine mammals and herbivTores have been experimentally infected with Trichinella spp. while Asatrian etI al. (2001) were also able to experimentally infect reptiles Lacerta agilis and ASgama caucasica with Trichinella spp. There is converging consensus that Rwastewater in altered sites are generally -1 characterized by hypereutrophication leaEding to very low DO in the sub 2mgl limits, high soil oxygen demand (SOD) dIueV to the resulting microbial action of chemotrophic and anaerobic microbes, respirNation of benthic invertebrates (Culp et al., 1983; Wetzel, 1983); increases in total cUarbon and chlorophyll a (Brenner et al., 1990); detritivous that speed up decomposi tion of retiring biota such as photosynthetic and chemotrophic algae leading to highN biomass input (Gale and Reddy, 1994); increases in total nitrogen (TN) and toDtal Aphosphorus (TP) as shown by the works of Huber et al.,1982 and Nordlie,A 1990. In particular relevance to the results of this study, Chironomids and OlIigBochaetes rely on constant substrate particle heterogeneity (Block et al., 1982; Culp et al., 1983 and Waters, 1995) leading to temporary nutrient renewal to the point where only such species tolerant of anorexic wastewater-sheds survive. When this occurs, Poeciliids such as P. reticulata usually survive these dramatic DO sinks by subsurface breathing of atmospheric oxygen (Meffe and Snelson, 1989) If all these were to be considered with the additional fact that infected Ciconiiform birds’ prefer foraging in recently disturbed watersheds devoid of emergent macrophytes then the enhanced prospect of complete E. ignotus infection cycle through 77 regular wastewater disturbance by excavation during monthly sanitation exercises in Lagos State becomes clearer. Where these birds defecate in wastewater drains but ingest newly exposed infected livebearer fish species such as G. affinis and P. reticulata, hitherto hidden in temporary sanctuaries, by recurrent monthly excavations, then multiple infections of both oligochaete and intermediate host Poeciliid fish occur culminating in increased E. ignotus intensity as against consistent level of prevalence that may not be affected by fish host re-infection. Results of the studies by Coyner et al. (2003) support this assertion. This may also explain the statistically significaYnt difference in drain based mean intensity of E. ignotus in P. reticulata obserAved Rin the current study. Perhaps the most important factors determining and enhancing iRnfection cycle of P. reticulata by E. ignotus in wastewater drains, in agreement wiIthB the conclusion of previous studies by Frederick and McGhee (1994), Brenner et aLl (1990) and Coyner et al. (2003) on similar drains in Florida, are the interplay inY constant release of domestic sewage in wastewater reaching drains on Lagos StreIetTs. High nutrient refluxes lead to high primary productivity at varying levels of eSutrophication. In order to ease waste- drain traffic flow, recurrent excavation of wRastewater substrate and drain soil leads to substrate renewal and soil particleV hetEerogeneity during monthly public sanitation exercises in Lagos State. I In effect, physicochemiNcal conditions in the wastewater drains play a significant role in determining trans itUional eutrophication in the drains (Snieszko, 1974; Akinwale and Ansa, 2004) throNugh environmental alteration that promote E. ignotus transmission (Coyner et al., 2A003 ). This spontaneity usually coincides with the loss of refugia to infected P. Dreticulata that are thereafter exposed to predation by piscivorous fish and CiconiifAorm birds. It is not very clear to what extent these monthly wastewater suIbsBtrate alteration helps in promoting the transmission of Trichinella spp., C. pterophylli and C. cotti in P. reticulata. Here however, unlike the report of Loftus and Eklund (1994) that the highest prevalence of E. ignotus in G. affinis was observed in the dry season in Florida, the highest monthly prevalence of E. ignotus in P. reticulata in this study was observed in May, 2004 during rain season in Lagos. Loftus and Kushlan (1987) also found out that the highest predation of piscivorous fish on Poeciliids occur in the Dry season in 78 Florida. There is no comparative study on predation of P. reticulata by piscivores in Nigerian in lotic and lentic waters or in wastewater drains. Nigeria is a developing economy with a growing need for expanding foreign exchange revenue base and profile. The needed growth is matched by the yawning gap in balance of trade between Nigeria and many of her major trading partners. Although, balance in trade is not only a desirable imperative but one of the conventional means of measuring the state of health and relative attractiveness of any national economy, yet an unbalanced economy is symptomatic of a poorly regulated and an insecure economYy (Ploeg et al., 2009). Nigeria’s dependence on petroleum-based foreign excRhange earnings as singular major revenue source is an example of such a monAo-cultural economy with inherent defects. Therefore, a gradual diversification of NiRgeria’s foreign exchange gross-earning portfolio such as can be enhanced throughI Brelatively low-risk and high-yield commerce engendered by the current state of inLternational ornamental fish trade is an unavoidable option. An option that wouldY eventually further facilitate greater employment opportunities, new skills acquisiItioTn, technology transfer along the entire value chain of local ornamental fish trade, Sindustrialization, ecotourism and other social collateral effects as experienced elsewRhere. However, the need to fundaVmenEtally secure Nigeria’s living aquatic borders from chance or deliberate infiltratIions and aggressions of exotic pathogen invasions leads to the desirability of propNerly assessing the current state of parasite and microbial load of indigenous ornam eUntal fish species and their major sister imports. The choice oNf P. reticulata for this study out of as many as forty ornamental fish species listeAd as commonly available for export in Nigeria by Areola (2004) was informed by its ubiquity in Lagos wastewater drains, its exotic nature and therefore its potentiaAl forD invasion and propagule pressure on existing ichthyofauna of wastewater and deliberate aquaculture of contiguous aquifer. The invasion of new biota and waIteBrsheds in Nigeria by P. reticulata and contemporary nematode fauna may as a result lead to new problems hence the need for this study. P. reticulata also retains the reputation of being the most widely sold freshwater ornamental fish in the world. This emphasizes the point that it is difficult to do a risk assessment of obtaining export grade of P. reticulata product without an examination of the objectives of export substitution in the absence of conscious reminder of the amount of foreign exchange earning 79 potential of P. reticulata that Nigeria could gain from developing a local export substitute to the various forms of P. reticulata modified for the market. It would be necessary to evaluate what Nigerian OFI clients expend in the import of P. reticulata as ornamental fish today, what is infrastructure to put in place to satisfy quality assurance and also what is needed to further conclude study on other non-nematode parasites of P. reticulata. So far none of the parasites found in this study are amongst the pathogens included in OIE list of identifiable diseases (OIE, 2003 and 2005). The fish diRseasYes listed under the OIE lists are Epizootic hematopoietic necrosis (EHN),Infectious hematopoietic necrosis (IHN), Spring viraemia of carp (SVC),Viral heAmorrhagic septicemia (VHS), Infectious pancreatic necrosis (IPN),Infectious saRlmon anemia (ISA), Epizootic ulcerative syndrome(EUS), Bacterial kidn eLy dIi Bsease (BKD) and Gyrodactylosis (caused only by Gyrodactylus salaris), Red sea bream iridoviral disease and Koi herpesvirus disease (KHV). Of all these, only tYhree (VHS, EUS and KHV) have been shown to affect ornamental fish species IalTl over the world while only the last, KHV can infect P. reticulata. Luckily for NSigerian ornamental fish mongers and o o exporters, KVH can only survive in its Rhost only below 17 C or above 25 C temperatures. Wastewater drain and VaquEaria temperatures in Nigeria are rarely outside this range thereby enhancing the exIport potential of P. reticulata from these drains. It is already clear that nNone of the four nematodes can be said to be indigenous to Nigerian clime. If the y Uare all exotic to Nigerian aquatic biota, then they must have been originally introNduced with the same or other exotic parasites in the far or recent past through accAidental or unethical disposal from aquaria settings. Further enlargement of this studDy would do well to note that transmission of autogenic against allogenic nematodAe parasites have comparative but contrasting niche, environmental, traInsBmission and trophic strategies (Dobson, 1986; Dobson, 1988 and Esch et al., 1990) for propagation hence the differences in their prevalence and intensity in P. reticulata. Proper risk abatement measures against the retention of these nematode parasites in export substitutes should therefore discriminate between these in its sourcing, quarantine and transportation focus. Other studies of this magnitude for the prevalence and mean intensity of protozoan and trematode parasites of P. reticulata deserve consideration as well. 80 Finally, the role of genetic facilitation and subversion of nematode parasitism by the P. reticulata host in the suitability of wastewater derived samples for export market substitution would not be comprehensive enough without a proper re-evaluation of possible speciation taking place in the current feral stock in Lagos drains as described by Webb et al. (2007) for Trichogaster trichopterus in Australian waters. It is suggested that DNA barcoding method of evaluating the evolutionary history of the Poecilia genus (Steinke et al., 2009) be done to ascertain how many species and strains of Poecilia are currently existing in these wastewater drains (Dawes, 1991). TRhis Yis beside same level of taxonomic scrutiny necessary for the attendant fish diseaAse causing pathogens observed in the ornamental fish hosts within the Nigerian biome since their current economic importance need proper validation. Spontaneous Rand dynamic changes may be already occurring in our freshwater and mari B nLe aqIuatic environments un-noticed as would be indicated by previous works by Whitfield (1979), Wallace (1961), Toft (1986), Barratt and Medley (1990), WilliamY and Jones (1994), Rigby et al., 1997 and Thomas et al. 2005 . IT There had been this special, albeit, unusuSal situation, where the rigor applied to the control of imported plant and animal caRrgo across borders are not applied to live ornamental fish species (Freyhof andV KoErte 2005) ostensibly because of their fragility and the need to reduce the impact Iof stress on them in order not to cause mortality en- route their destination. ConseNquently, the trans-border transportation of ornamental fishes occurs at times i n Ularge volume in most parts of the world and is done by virtually anyone wNith little hindrance because they are somehow considered as harmless pets. RealDizatiAon of the potential risks of pathogen transfer through ornamental fish imports (Langdon 1988; Read, 1990; Rowland and Ingram 1991; Dove et al. 1997; DoIvBe 19 A98; 2000; Dove and Ernst 1998; Dove and Fletcher 2000) only became critical relatively recently in comparison with those of other animal imports. In Nigeria, the import of ornamental fish is now regulated under the Live fish (Control of importation) Decree 209 of 1990 (See Volume XI of laws of the Federation of Nigeria, 2000). In New Zealand, it was previously considered under the Biosecurity Act of 1993 but now modified in the Hazardous Substances and New Organisms Act of 1996. There, only exotic ornamental fish species of tropical origin that are known not to be able to survive the temperate condition of New Zealand have been further allowed on the permitted list 81 for imports. As a result, ornamental fish species of temperate origin such as the Goldfish (Carassius auratus) and carp (Cyprinus spp.) are not on the permitted list of imported ornamental fish into New Zealand. Even then, the presence of geothermal streams and artificial warm water bodies in some northern parts of New Zealand, in addition to continuing climatic changes induced by gradual global warming ultimately mimic tropical conditions. These geothermal stream have been confirmed by the New Zealand Freshwater Fish Database (2005) to now sustain local populations of four major tropical species of ornamental fish species such as the guppy (P. reticulata), thYe sailfin mollies (Poecilia latipinna),the swordtail fish (Xiphophorus helleri), anRd the caudo (Phallocerus caudimaculatus). These species were previously considerAed safe in New Zealand because of the thought that their characteristic pathogensR would hardly survive in the temperate condition of the country not surprisingly asI eBxperienced by the studies and reviews of Poulin (2002); Pigliucci and Murre n L(2003). By extension, global warming realities would demand that Nigeria devYelops a more comprehensive risk map and mitigating measures that can officiallyI sTcreen for potential pathogens of both tropical and temperate origin in ornamental Sfish imports. Such ornamental imports may inadvertently adapt to Nigeria’s climaRte and establish themselves in local fish populations because of thinning climVatic Ebarriers (May, 1988 and Dobson, 1990). Furthermore, ongoing globaIl climate changes could already be impacting on the local stock of P. reticulata exNisting in wastewater drains thereby amplifying possible endemicity of nematode pUarasites or establishment of exotic ones on this ornamental fish species (May anNd Anderson, 1979; Dobson, 1988; Pigliucci, 2001; Buckling and Rainey, 2002; PAoeser, 2011). In the event that these occur, aggressive infusion or spontaneousD invasion of Nigeria’s wastewater biosphere (Esch et al., 1975; Fuller et al., 199A9 and Dunn, 2005) possibly occasioning loss of germplasm may result (CIouBrtenay and Meffe, 1989; Gozlan et al., 2010). Obtaining empirical data on the parasites of P. reticulata is therefore critical to its prospects in the Nigerian segment of the OFI (Dobson, 1986; Courtenay and Stauffer, 1990 and Courtenay and Moyle, 1996). Symptom of diseases in ornamental fish kept in aquaria are easily treated at that macrocosmic level however making the fish pet survive and continue as a carrier of the germ (Arthington, 1989a; Courtenay and Robbins, 1989 ). When sanitation of aquarium tanks or unintended escape of ornamental fish take place, accidental translocations to 82 wastewater drains often occur thereby making native fish species in the drains that are susceptible to the parasites become new hosts (Arthington and Lloyd, 1989). Oftentimes, these new hosts are food fish species (deGraaf et al., 1995) with potential for transferring these parasites to humans (Arthington, 1989b; Moyle and Li, 1994). Though many freshwater ornamental fish species number amongst the export list from Nigeria destined for the US, EU and South East Asia (Mbawuike and Pepple, 2003; Mbawuike et al., 2004; Mbawuike and Ajado, 2005) the potential for the more economically rewarding marine species of ornamental fish species are wide becaRuse Yof the many deep water wrecked abandoned vessels in Nigeria’s Exclusive Economic Zone (EEZ). Coral reefs that result from some of these ship wrecks hRaveA for years constituted refugia for the many colonizing invading poriferans and ichthyofauna that constitute highly financially rewarding gains in the ornamenta l fLishI m Barket (Larkin and Degner, 2001; Larkin et al. 2003) elsewhere in the US. Same potential exists in deep waters of Nigeria’s EEZ. Perhaps, the major factor militYating against a repeat of the wanton destruction of these deep water habitats for IexTploitation of deep water marine ornamental fish species is the absence of deep Swater divers in Nigeria unlike in the Southeastern coast of Africa in the SeychelleR islands and Mauritania. The taxonomy of Capillaria spp.E has clearly been under constant review while the true status of parasitic finds in IfoVod-fish and ornamental fish species are also being validated by molecular biologNy methods (Moravec and Gut, 1982; Paperna, 1996). Another case in point is thUe occurrence of Trichinella spp. in P. reticulata in this study that suggest a host-par asite species barrier conquest because Trichinella spp. are nematode parasiAtes oNf feline mammals and not previously encountered in fish samples (Murrell et aDl., 2000; Bruschi and Murrell, 2002). This is just as Moravec et al. 1990 in their firAst record of Raphidascaris (Sprentascaris) hypostomi occurrence in Brazil quIesBtioned the taxonomic status of the host genus Sprentascaris. Moravec et al. (1998a) similarly made new observations of Mexiconema cichlasomae (Nematoda: Dracunculoidea) from fishes of Mexico. Furthermore, Moravec et al, 1998b found fish as paratenic host of Serpinema trispinosum while the report by Gonzalez and Hamann (2007) explained the new role of the amphibian, Lysapsus limellum Cope, 1862 (Amphibia: Hylidae) as new paratenic host in the life cycle of Serpinema trispinosum (Nematoda: Camallanidae). 83 All these reports were initially controversial. Further validation of these startling identifications of fish parasites, unusual fish and other taxa as paratenic hosts through molecular biology techniques would be necessary to settle grey areas generated by their discovery (Bondad-Reantaso et al., 2005; Bolton and Graham, 2006). It would not be surprising if current helminthic parasite fauna of freshwater ornamental fish species already over-reach the limits set by the checklist of Khalil and Polling (1997). On-going genetic characterization of parasites species using DNA barcodes seem to hold contemporary sway in parasitology and Nigerian Scientists would need to plaYy active roles. This is necessary because legal disputes of the future on control Aof nRatural aquatic resources, determination of assets and the burden of its liability, in the face of panoply of natural disasters, may very well be based on the possession Rof intellectual property accessions to buttress claims to natural assets of regionaIl Bscope. Indeed, the world’s living aquatic resources have moved far from thYe w or Lks of Linnaeus (1758) while the P. reticulata of Peters (1859) is actively under review. Import and export records from Custom autIhTorities and FAO in virtually all points of origin and destination of ornamenStal fish are currently, scientifically unreliable as regards true origin and deRfendable taxa of these organisms. The impeccability of DNA barcodes thatV empEloys the use of a short stretch (685 bp) of the mitochondrial DNA of all organismIs to evolutionarily profile and identify organisms is clear (Steinke et al., 2009). It Nis the newest approach to trans-border traffic control of pets. Practically and relatiUvely less invasive than other methods, with the collection of hairs, blood sample and fish skin snipes immediate confirmation of the true cluster of origin of an ornAameNntal fish can be generated and transmitted to and from globally accessible iDnternet servers to obviate for some of the expensive and tortuous certificaAtion mechanisms put in place by UNCTAD, CITES and OIE that stifles true freIe Btrade amongst nations. Meanwhile, there are more marine ornamental fish species that draw greater profit per unit catch and sale in the export than the freshwater species (Chan and Sadovy, 1998 and 2000) even when greater care as enunciated by (Chao, 1992; 1993; Chao and Prang, 1997 and Chao, 2001) has to be ensured to conserve our natural marine and coastal reefs from irresponsible fishing methods. To source, warehouse, trade and retain ornamental fish assets, adoption of DNA barcoding methods for profiling therefore seem unavoidable. 84 The Nigerian state may be in possession of assets whose currency and validity has since long ago changed. We have to be actively involved in all relevant and current research, in a global knowledge economy, where possession of natural resources are validated by only intellectual property development of such resources for economic access. It is poetic that such nations of the world lacking in natural resources with a surfeit of natural disasters (temperate regions, inclement weather conditions, earthquakes, Tsunamis, Hurricanes forest fires and landslides) but that attach great policy and implementation premium to human capital development such as JapaYn, Malaysia, EU, China and the US are far ahead of those endowed with natural resoRurces (such as Nigeria and Democratic Republic of Congo) in the productRive hAarness of natural resources. LIB Y T RS I E NI V U N A D A IB 85 CHAPTER SIX CONCLUSIONS Prevalence of E. ignotus, Trichinella spp. C. pterophylli and C. cotti in P. reticulata obtained from Igi-Olugbin, Basil Ogamba, Ahmadu Bello and Adenaike Alagbe Streets of Lagos State is neither sex-related nor drain-related though monthly mean intensity differed significantly with drains. Therefore, the collection of P. reticulata from the above Streets for exploring their export potential is safe as regardYs intolerable nematode infections and intensity. R Access of terrestrial household pets and animals such as stray cAats, dogs, poultry, ducks and wading water birds to wastewater drains where coRllections of P. reticulata is to be made should be limited if not totally avoided. ITBhis is because the observed nematode parasites and others such as nonY-ne m Latode helminthes and protozoan parasites need these occasional visitors toT wastewater drains to complete their cycle. Similarly, the monthly sanitation exerIcise in Lagos State that entails, amongst other activities, the clearing of drains byS removal of debris and soil substrates onto the main road turn out to be countRer-productive to the effort in stemming nematode parasite cycle completionsV. ThEis so because the excavated debris are in many cases not evacuated away from theI point of deposition near the drains with subsequent rains washing the sewage debNris and nutrients back into the drains thereby increasing eutrophication of wastewaUter. These high nutrient load, sewage debris and flood water renewal expose reguNlar refugia of P. reticulata making them revealed preys to avian and quadruped pAredators. The attraction of wading birds and the release of their fecal matter into Dwastewater particularly enhance recurrent E. ignotus egg loading of the wastewaAter. IBIt is also advised that animal carrion be properly disposed away from the drains. An alternative means of preventing all these is the use of well covered drains inaccessible to occasional visitors. Monitoring of ornamental fish aquaculture and trade through regular review of risk assessment and mitigation plans should be directed at socio-economic gains and biological conservation of these species. Since, the proper genetic characterization of these organism are critical to possession and access, it is recommended that the use of DNA barcoding method of identification be adopted for both ornamental fish and their parasite fauna to stave off inhibitory litigation cost that 86 may result from unfair trade practices injurious to Nigeria’s economy in the near future. This would also be important in determining dynamic level of speciation expected to be under serious yield to climate change, the origin, wild or domestic nature of fish samples and their parasites, forensic confirmation of source of harvest, route of import and method of obtaining them which would ultimately reduce licensing and certification cost for Nigerian traders and exporters. RY BR A I L SI TY ER IV U N AN BA D I 87 REFERENCES Acho-Chi, C. 2001. Management of water supply systems in the Kano district of Nigeria: Problems and Possiblities. Aqua 504:199-207. Y Adel, N., Rashed, M. A. and Rizkalla, E. H. 2003. An experimental trial for infRecting the scavenger catfish Clarias lazera with Trichinella spiralis larvae wAith special reference to certain fish biochemical reactions. Egyptian JournRal of Aquatic Biology and Fisheries 7.3:173- 195. B Akinwale, M.M.A. and Ansa, E. 2004. The impact of varyiLng Inutrient regimes in earthen freshwater ponds on the comparative ecoYlog y of diurnally occurring thcandidate live feeds. Proceeding of the 19 AInTnual Conference of the Fisheries th rdSociety of Nigeria FISON. 29 November-3 December, 2004. Araoye, P.A. Ed. Ilorin, Nigeria.787-795. S Akinwale, M.M. A., Keke, R.I. and EgEenoRnu, C. 2007. Bacterial microflora of the African catfish Clarias gaVriepinus juveniles raised under fish cum pig integrated farming system Iin freshwater earthen ponds during the dry season. Nigerian Journal of FisNheries 4.2: 91-104. Akinwale, M.M. A., KekeU, R. I., Ibeh, C. and Edun, M.O. 2004. Ecology of bacterial microflora ofN ooc yte incubation and compromise in Heterobranchus bidorsalis during thAe critical breeding failure months. Nigerian Society for Experimental BioloDgy Journal 4.2:75-82. AlexandAer, H.J. and Breden, F. 2004. Sexual isolation and extreme morphological IBdivergence in the Cumana guppy: a possible case of incipient speciation. Journal of Evolutionary Biology 17. 6:1238-1254. Anderson, N. and Waller, P. J. 1985. Resistance in nematodes to antihelminthic drugs. CSIRO Division of Animal Health, Glebe, Australia. Anderson, R. C. 1988. Nematode transmission patterns. Journal of Parasitology 74: 30. Anderson, R.C. 1996. Why do fish have so few roundworms nematode parasites? Environmental Biology of Fish 46:1–5. 88 Anderson, R M. and May, R. M. 1985. Helminth infections of humans: Mathematical models, population dynamics and control. Advances in Parasitology 24: 1. Anderson, R. M. and. May, R. M. 1979. Population biology of infectious diseases I. Nature 1.280: 361-367. Andrews, C. 1990. The ornamental fish trade and conservation. Journal of Fish Biology 37:53–59. Andrews, C., Chubb, J.C., Coles, T. and Dearsley, A. 1981. The occurrence of Bothriocephalus acheilognathi Yamaguti, 1934 B. gowkongensis CestodYa: Pseudophyllidea in the British Isles. Journal of Fish Disease 4: 89-93. R Anogwih, J.A. and Makanjuola, W.A. 2010. Predator-prey density ofA Poecilia reticulata guppy under laboratory investigation. The Zoologist 8: R47-51. th APHA. 1998. Standard methods for the examination of water aLnd Iw Bastewater 20 Ed. American Public Health Association, L. S. ClescerrYi, A. E. Greenberg and A. D. Eaton. Eds. Washington, DC. Areola, F. O. 2003. Trends in Live Fish Export AITctivities in Nigeria: 1996-2000. Proceedings of the Fisheries Society OSf Nigeria FISON Conference. 2003. Owerri, Nigeria. 206-211. R Areola, F. O. 2004. Export PoVtentiEal of Ornamental Live Fishes in Nigeria. thProceedings of the FisherIies Society Of Nigeria FISON Conference. 29 rd November-3 DecembeNr, 2004. Araoye, P.A. Ed. Ilorin, Nigeria. 589-596. Arthington, A.H. 1989a. DUiet of Gambusia affinis holbrooki, Xiphophorus helleri, X. maculatus, anNd Poecilia reticulata Pisces: Poecilidae in streams of southeastern QueenslaAnd, Australia. Asian Fisheries Sciences 2: 193-212. Arthington, DA.H. 1989b. Impacts of introduced and translocated freshwater fishes in AAustralia. P. 7-20. Exotic Aquatic organisms in Asia. Proceedings of the IBWorkshop on introduction of exotic aquatic organisms in Asia. Asian Fisheries Society. Special Publication. 3. 154. Asian Fisheries Society. de Silva, S. S. Ed. Manila, Philippines. Arthington, A. H. and Lloyd, L. N. 1989. Introduced poeciliids in Australia and New Zealand. Ecology and evolution of live bearing fishes Poeciliidae. Prentice Hall, Englewood Cliffs, Meffe, G.K. and F.F. Snelson, Jr., Eds. New Jersey, USA. 333–348. 89 Arthur, J. R. and Lumanlan‐Mayo, S. 1997. Checklist of the parasites of fishes of the Philippines.FAO Fisheries Technical Paper.Food and Agricultural Organization of the United Nations 369:102. Asatrian, A.., Movsessian, S. and Gevorkian, A. 2001. Experimental infection of some reptiles with Trichinella spiralis and Trichinella pseudospiralis. Journal De la Societe Francaise de Parasitologie, 8:2.102-147. Baerends, G. P., Brouwer, R. S. and Waterbolk, H. T. J. 1955. Ethological studies oYn Lebistes reticulata Peters I.An analysis of the male courtship pattern. Behaviour 8.249-334. R Barratt, L. and Medley, P. 1990. Managing multi-species ornamental RreefA fisheries. Progress in Underwater Science 15:55-72. B Block, E. M., Moreno, G. and Goodnight, C. J. 1982. Observa tiLon oIn the life history of Limnodrilus hoffmeisteri Annelida, Tubificidae froYm the Little Calumet River in temperate North America. International JournTal of Invertebrate Reproduction 4: 239–247. I Bolton, T. F. and Graham, W. M. 2006. JellyfishS on the Rocks: Bioinvasion Threat of the International Trade in Aquarium RLive Rock. Biological Invasions 84: 651- 653. E Bondad-Reantaso, M. G., SubasinIghVe, R. P., Arthur, J. R., Ogawa, K., Chinabut, S., Adlard, R., Tan, Z. anNd Shariff, M. 2005. Disease and health management in Asian aquaculture . UVeterinary Parasitology 1323-4: 249-27227 Boyd, C. E. 1990. NWater quality in ponds for aquaculture. Agriculture Experiment Station, AAuburn University, Auburn, USA. 482pp. Boyd, C. ED. 1995. Bottom soils, sediment, pond aquaculture. New York, USA: CAhapman and Hall. 348pp. BrIenBner, M., Binford, M. W. and Devey, E. S. 1990. Lakes. Ecosystems of Florida. R. L. Meyers and J. J. Ewel. Eds. Orlando, Florida: University of Central Florida Press. 364–391. Brown, R. B., Stone, E. L. and Carlisle, V. W. 1990. Soils. Ecosystems of Florida. R. L. Myers and J. J. Ewel. Eds. Orlando, Florida: University of Central Florida Press. 35–69. Bruschi, F. and Murrell, K. D. 2002. New aspects of human Trichinellosis: the impact of new Trichinella species. Postgraduate Medical Journal 78:15-22. 90 Buckling, A. and Rainey, P. B. 2002. The role of parasites in sympatric and allopatric host diversification. Nature 420.6915: 496-499. Campbell, W. C. 1983. Epidemiology: Modes of transmission. Trichinella and Trichinosis. W. C. Campbell. Ed. New York: Plenum Press. 425-444. Canonico, G. C., Arthington, A., Mccrary, J. K. and Thieme, M. L. 2005. The effects of introduced tilapias on native biodiversity. Aquatic Conservation of Marine and Freshwater Ecosystem 15: 463–483. Chan, T., and Sadovy, Y. 1998. Profile of the marine aquarium fish trade in HonYg Kong. Aquarium Sciences and Conservation 2: 197-213. R Chan, T. T. and Sadovy, Y. 2000. Profile of the Marine Aquarium Fish TradAe in Hong Kong. Aquarium Sciences and Conservation 24: 197-213. R Chao, N. L. 1992. Diversity and conservation of ornamental fishIesB - the gems from flooded forests in Amazonia. Canadian Biodiversity 2 2 :L 2-7. Chao, N. L. 1993. Conservation of Rio Negro orTnamYental fishes. Tropical Fish Hobbyist 41 5: 99-114. I Chao, N. L. 2001. Fisheries, diversity and conseSrvation of ornamental fish of the Rio Negro River, Brazil - a review of PRroject Piaba 1989-99. In Chao, N. Petry, P.Prang, G. Sonnieschien, VL. Eand M. Tlusty. Eds. Conservation and Management of OrnamentaIl Fish Resources of the Rio Negro Basin, Amazonia, Brasil – ProjectPiaba. N Manaus, Brazil: University Of Amazonas Press Pp. 161- 204. U Chao, N. L. and PrNang, G. 1997. Project Piaba - towards a sustainable ornamental fishery in the Amazon. Aquarium Sciences and Conservation 1: 105-111. Chapman, FD. A.A, Fitz-Coy, S. A., Thurnberg, E. M. and Adams, C. M. 1997. United SAtates of American trade in Ornamental fish. Journal of World Aquaculture IBSociety 28:11-10. 3. Chervinski, J. 1984. Salinity tolerance of the guppy, Poecilia reticulata Peters. Journal of Fish Biology 24.4: 449–452. Chou, L. M., Tuan, V. S., Yeemin, T., Cabanban, A., Suharsono, A. and Kessna, I. 2002. Status of Southeast Asia coral reefs. Status of coral reefs of the World: R.C. Wilkinson. Ed. Australian Institute of Marine Science, Townsville.123- 152. 91 Claydon, J. 2005. Spawning aggregations of coral reef fishes: Characteristics, hypotheses, threats and management. Oceanography and Marine Biology 42:265-301 Cole, D. J., Hill, V. R., Humenik, F.J. and Sobsey, M. D. 1999. Health, Safety and Environmental concerns of farmed animal waste. Occupational Medicine 14:423-448. Conroy, D. A. 1975. An evaluation of the present state of world trade in ornamental fishes. FAO, Rome, Italy.28 Conroy, D.A. 1977. Evaluation of the Present StaYte of World Trade in Ornamental Fish. Copeia 1977.2: 410-411 R Corfield, J., Diggles, B., Jubb, C., McDowall, R. M., Moore, A., RichardAs, A. and Rowe, D. K. 2008. Report to the Australian Government DepaRrtment of the Environment, Water, Heritage and the Arts: review of t he imIp Bacts of introduced ornamental fish species that have established wild poLpulations in Australia. NIWA, Australia, Queensland. Y Courtenay, Jr. W. R. 1999. Aquariums and water gIarTdens as vectors of introduction. Non indigenous Freshwater OrganismSs: Vectors, Biology, and impacts R, Claudi. and J. H. Leach, Eds. Lewis PRublishers. Boca Raton: 127–128. Courtenay, W. R., Jr. and Meffe, GV. K. E1989. Small fishes in strange places: a review of introduced poeciliids..I Ecology and evolution of livebearing fishes Poeciliidae. G.K. MeffNe and F.F. Snelson, Jr., Eds. Prentice Hall. Englewood Cliffs, New Jersey:U 319–331. Courtenay, W. R., JrN. Mo yle, P. B. 1992. Crimes against biodiversity: the lasting legacy of fish iAntroductions. Northern American Wildlife and Natural Resources Conference Transactions 57: 365-382. CourtenAay, DW. R., Jr. and Moyle, P. B. 1996. Biodiversity, fishes, and the introduction IBparadigm.. Biodiversity in managed landscapes: theory and practice. R.C. Szaro and D.W. Johnston, Eds. New York: Oxford Univ. Press. 239 –252. Courtenay, W. R., Jr. and Robins, C. R. 1989. Fish introductions: Good management, mismanagement, or no management? Reviews in Aquatic Science 1: 159–172. Courtenay, W. R., Jr., and Stauffer, J. R. Jr. 1990. The introduced fish problem and the aquarium fish industry. Journal of the World Aquaculture Society 21:145- 159. 92 Coyner, D. F., Spalding, M. G. and Forrester, D. J. 2003. Epizootiology of Eustrongylides ignotus in Florida: transmission and development of larvae in intermediate hosts. Journal of Parasitology 89.2: 290-298. Cram, E. B. 1941. Trichinella Spiralis. In, Chitwood, M.B, (Ed.) An Introduction to Nematology. Babylon, New York, 11. 2:216-318. Culp, J. M., Walde, S. J. and Davies, R. W. 1983. Relative importance of substrate particle size and detritus to stream benthic macroinvertebrate microdistribution. Canadian Journal of Fisheries and Aquacultural Sciences 40: 1568–1574. Y Curry, T. 2009. Culture of Nigeria - history, people, clothing, traditions, wRomen, beliefs, food, customs, family. Retrieved on Aug. 3, 201A2 from. http://www.everyculture.com/Ma-Ni/Nigeria.html#b R Dawes, J. A. 1991. Livebearing Fishes: A Guide to Their Aqu aLriumI BCare, Biology and Classification. London, England: Blandforn. deGraaf, G. J., Galemoni, F. and Banzoussi, B. 1995. ThYe artificial reproduction and fingerling production of the African catfish CIlaTrias gariepinus Burchell 1822 in protected and unprotected ponds. AquaculSture Research 26: 233-242. Dobson, A. P.1986. The population dynaRmics of competition between parasites. Parasitology 91:317. E Dobson, A. P. 1988. The populaItVion biology of parasite-induced changes in host behavior. Quarterly RevNiew in Biology 63:139. Dobson, A. P. 1990. MUodels for multi-species parasite-host communities. The Structure of NParasite Communities.. G. Esch, C. R. Kennedy, and J. Aho, Eds. New York and London: Chapman and Hall. 261-288. Dove, A. DD. M.A 1998. A silent tragedy: parasites and the exotic fishes of Australia. PAroceedings of Royal Society of Queensland. 107: 109-113. DoIvBe, A. D. M. 2000. Richness patterns in the parasite communities of exotic poeciliid fishes. Parasitology 120: 609‐623. Dove, A. D. M., Cribb, T. H., Mockler, S. P. and Lintermans, M. 1997. The Asian fish tapeworm, Bothriocephalus acheilognathi, in Australian freshwater fishes. Marine Freshwater Research 48: 181-183. Dove, A. D. M. and Ernst, I. 1998. Concurrent invaders – four exotic species of Monogenea now established on exotic freshwater fishes in Australia. International Journal of Parasitology 28: 1755-1764. 93 Dove, A. D. M. and Fletcher, A. S. 2000. The distribution of the introduced tapeworm Bothriocephalus acheilognathi in Australian freshwater fishes. Journal of Helminthology 74: 121-127. Dudgeon, D., Arhtington, A. H., Gessner, M. O., Kawabata, Z. I., Knowler, D. J., Leveque, C., Naiman, R. J., Prieur-Richards, A. H., Soto, D., Stiassny, M. L. J. and Sullivan, C. A. 2006. Freshwater biodiversity: importance, threats, status and conservation challenges. Biological Review 81:163-182. Duggan, I. C., Corinne A. M., MacIsaac, H. and MacIsaac, R. J. 2006. Popularity anYd propagule pressure: determinants of introduction and establishment ofA aquRarium fish. Biological Invasions 8: 377–382. Dunn, A. L. 2005. Parasitic manipulation of host life history and sexRual behaviour. Behavioral Processes 68: 255-258. IB Eldredge, L. G. 2000. Non-indigenous freshwater fishes, Yamp h Libians, and crustaceans of the Pacific and Hawaiian islands. Invasive sTpecies in the Pacific: A technical review and draft regional strategy. SherleyI, G. Ed. South Pacific Regional Environment Programme, Apia, Samoa. 1S73-190 Esch, G. W., Bush, A. O. and Aho, J. M. 1R990. Parasite communities: patterns and processes. London: Chapman & HEall. Esch, G. W., Gibbons, J. W. and BIoVurque, J. E. 1975. An analysis of the relationship between stress and paraNsitism. American Midland Nature 93:339 - 353. ESRI.2011.ArcGIS Desk tUop Release 10. Redlands, California, USA. Environmental Systems ReseNarch Institute. Fadama III. 2011A. Profile of Lagos. Official website of the National Fadama deveDlopment Project. Retrieved on April 19, 2011 from hAttp://www.fadama.net/HTML/state_details.php?state=Lagos. FaIkoBya, K. A., Owodeinde, F. G., Jimoh, A. A. and Akintola, S. L. 2004. An overview of the challenges and prospects of developing an aquaculture industry in Lagos th State, Nigeria. Proceeding of the 19 Annual Conference of the Fisheries th rd Society of Nigeria FISON, 29 November-3 December, 2004. Araoye, P.A. Ed. Ilorin: 500-511. FAO. 1997. FAO Database on Introduced Aquatic Species. Food and Agriculture Organization of the United Nations FAO, Rome, Italy. 94 Font, W.F. 2003: The global spread of parasites: What do Hawaiian streams tell us? BioScience 53: 1061–1067. Font, W. F. and Tate, D. C. 1994. Helminth parasites of native Hawaiian freshwater fishes: an example of extreme ecological isolation. Journal of Parasitology 80:682– 688. Forch, G. and Bremann, H. 1998. Restoration of water supply schemes in the context of town development: The Bhaktapur project in Nepal. Applied Geography anYd Development 15:54-61. Frederick, P. C., and McGehee, S. M. 1994. Wading bird use of wastewater treaRtment wetlands in central Florida, USA. Colonial Waterbirds 17: 50–59.R A Frederick, P. C., McGehee, S. M. and Spalding, M. G. 1996. Prevalence of Eustrongylides ignotus in mosquitofish Gambusia holIbrBooki in Florida: Historical and regional comparisons. Journal of WiYldlif e LDisease 32: 552–555. Freyhof, J. and Korte, E. 2005. The first record ofT Misgurnus anguillicaudatus in Germany. Journal of Fish Biology 66: 568–57I1. Froese, R and Pauly, D. 2007. FishBase 2007. "PSoecilia reticulata" in FishBase. April 2007 version. Retrieved Apr. 5, 2009 Rfrom http //: www. fishbase.org. Fujita, T. 1927. On new species oVf nEematodes from fishes of Lake Biwa. Japan. Journal of Zoology 1:169–1I76. Fuller, P. L., Nico, L. G and WNilliams, J. D. 1999. Non indigenous fishes introduced to inland waters o f Uthe United States. American Fisheries Society Special Publication NNo. 27. Bethesda, Maryland, American Fisheries Society. Gale, P. M. and AReddy, K. R. 1994. Carbon flux between sediment and water column of a Dshallow, subtropical hypereutrophic lake. Journal of Environmental Quality 2A3: 965–972. GeInBthe, B. and Seager, J. 1996. The effect of water supply, handling and usage on the water quality on health indices in developing communities. Water Research Commission Report 562.1: 96. Gonzalez, C.E. and Hamann, M.I. 2007. The first record of amphibians as paratenic hosts of Serpinema larvae (Nematoda; Camallanidae). Brazilian Journal of Biology 67.3:579-580. Gozlan, R. E., Britton, A., Cowx, I. and Copp, G. H. 2010. Current knowledge on non- native freshwater fish introductions. Journal of Fish Biology 76: 751-756. 95 Grabow, W. O. K. 1996.Waterborne diseases: Update on water quality assessment and control. Water South Africa 10: 17-14. Hargrove, Maddy and Hargrove, Mike 2006. Freshwater Aquariums for Dummies 2nd ed. Hoboken: Wiley. Retrieved on April 5, 2009 from http://akvas.net/articles_files/Freshwater%20Aquariums%20for%20Dummies.p df. Houde, A.E.1997. Sex, Color, and Mate Choice in Guppies. Princeton, NJ: Princeton University Press. Y Huber, W. C., Heaney, J. P., Aggidis, D. A., Dickinson, R. E., Smolenyak, K.. RJ. and Wallace, R. W. 1982. Urban Rainfall-Runoff-Quality Data BasRe, EPAA-600/2-81-238 (NTIS PB82-221094), Cincinnati, OH: U.S. Environ Agency. IBmental Protection Hulme, P. E. 2009. Trade, transport and trouble: managing in vLasive species pathways in an era of globalization. Journal of Applied EcoloYgy 46: 10–18. IUCN. 2001. 100 of the world's worst invasive alIieTn species: a selection from the global invasive species database. InvasiSve Species Specialist Group, IUCN, Auckland. R Kennedy, C. E. J., Endler, J. A., PoVyntoEn, S. L. and McMinn, H. 1987. Parasite load predicts mate choice in gIuppies. Behavioral Ecology and Sociobiology 21: 291‐295. N Khalil, L. F. and Pollin gU, L. 1997. Checklist of the helminth parasites of African freshwater fisNhes. University of the North. Republic of South Africa. Kim, H., HaywaArd, C. J. and Heo, G. 2002. Nematode worm infections Camallanus cottiD, Camallanidae in guppies Poecilia reticulata imported to Korea. AAquaculture 205. 2002: 231– 235. KlIinBger, R. E. and Floyd, R. F. 1998. Introduction to Freshwater fish parasites. Circular No. 716 of Department of Fisheries and Aquatic Science, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Ko, R. C. 1995. Fish‐borne parasitic zoonoses. Fish Diseases and Disorders: Protozoan and Metazoan Infections. P. T. K. Woo. Ed. Oxon: CAB International 1: 631‐671. 96 Kolar, C. S and Lodge, D. M. 2001 Progress in Invasion Biology: Predicting Invaders. Trends in Ecology and Evolution 16: 199–204. Lacorchak, J. M., Klem, D. J. and Peck, D. V. 1998. Environmental monitoring and assessment program-Surface waters: Field operations and methods for measuring the ecological condition of wadable streams. EPA/620/R- 94/004F.US Environmental Protection Agency, Washington DC. Langdon, J .S., Humphrey, J. D., Williams, L. M. 1988. Outbreaks of EHNV-like indovirus in cultured rainbow trout, Salmo gairdneri Richardson, In AustralYia Journal of Fish Diseases 11: 93-96. R Larkin, S. L. and Degner, R. L. 2001. The U.S. Wholesale MarkRet foAr Marine Ornamentals. Aquarium Sciences and Conservation 31.3: 13-24. Larkin, S. L., Adams, C .M., Degner, R. L., Lee, D. J. and MLilIon B, J. W. 2003. An Economic Profile of Florida’s Marine Life IndustryY. Sea Grant Technical Paper Number 113.November, 2001 Project No. R/LRT-A-23 Lawal, M. O. and Samuel, O. B. 2010. InvestigatioIn of acute toxicity of pirimiphos- methyl (Actellic, 25%EC) on guppy S(Poecilia reticulata, Peters, 1859). Pakistani Journal of Biological ScienRces 15.13(8):405-408. Lehlossa, L. J. and Muyima, N. VY. OE. 2000. Evaluation of household treatment procedures on the quality oIf groundwater supplies in the rural communities of the Victoria district. EaNstern Cape. Water South Africa 262285-290. Levsen, A. 2001. Trans mUission Ecology and Larval Behaviour of Camallanus cotti (Nematoda, NCamallanidae) Under Aquarium Conditions. Aquarium Sciences and Conservation 3: 301‐311. Levsen A. DandA Jakobsen P.J. 2002: Selection pressure towards monoxeny in CAamallanus cotti (Nematoda, Camallanidae) facing an intermediate host IBbottleneck situation. Parasitology 124: 625–629. Liley, N. R. 1966. Ethological isolating mechanism in four sympatric species of Poecilid fishes. Behaviour 13: 1-195. Lindholm, A. K., Breden, F., Alexander, H. J., Chan, W. K., Thakurta, S. G. and Brooks, R. 2005. Invasion success and genetic diversity of introduced populations of guppies Poecilia reticulata in Australia. Molecular Ecology 14:3671-3682. 97 Linnaeus, C. 1758. Systema Naturae, Ed. X. Systema naturae perregna tria naturae, secundum classes, ordines, genera,species, cum characteribus, differentiis, synonymis, locis.Tomus I. Editio decima, reformata. Holmiae. Systema Naturae, Ed. X. v. 1: i-ii + 1-824. Livengood, E. J. and Chapman, F. A. 2007: The ornamental fish trade: An introduction with perspective for responsible aquarium. IFAS Cooperative extension service No. FA124. Institute of food and agricultural science, University of Florida Gainesville FL 32611 retrieved on March 11, 2011 RfroYm http://edis.ifas.ufl.edu/pdffiles/FA/FA12400.pdf. Lodge, D. M.., and Shrader-Frechette, K. 2003. Nonindigenous speciRes: Aecological explanation, environmental ethics, and public policy. BioloIgBical Conservation 171: 31-37. Loftus, W. F. and Eklund, A. M. 1994. Long-term dynami csL of an Everglades fish community. In S. M. Davis and J. C. Ogden (Eds.Y) Everglades, the Ecosystem and its Restoration. Delray Beach, FL, USA: SItT. Lucie Press. Loftus, W. F. and Kushlan,J. A. 1987. FreshwatSer Fishes of Southern Florida. Bulletin of Florida State Museum. BiologicalR Sciences 31: 146 -343. MacLean, J. B., Viallet, J., Law, C. andE Staudt, M. 1989. Trichinosis in the Canadian Arctic: report of five outIbrVeaks and a new clinical syndrome. Journal of Infectious Diseases 160N: 513-520. Manna, B., Aditya, G. a nUd Banerjee, S. 2008. Vulnerability of the mosquito larvae to the guppies PNoecilia reticulata in the presence of alternative preys. Journal of Vector BAorne Diseases 45: 200-206. Margolis, LD., Esch, G. W., J. C. Kuris, A. M. and Schad, G. A. 1982. The use of eAcological terms in parasitology (Report of an Adhoc Committee of the IB merican Society of Parasitologists). Journal of Parasitology 68:131-133. May, R.M. 1988. How many species are there on earth? Science 241:1441. May, R.M. and Anderson, R. M. 1979. The population biology of infectious diseases: II. Nature 280.2: 455-461. Mbawuike, B. C. and Ajado, E. 2005. Assessment of Ornamental fish species and fishing methods in Ibiajegbende, Lagos state, Nigeria. African journal of Applied zoology and Environmental Biology 1.7: 23 – 27. 98 Mbawuike, B. C., Chukwurah, D. I. and Ajetunmobi. O. M. 2004. Ornamental fish transportation in Nigeria. African Journal of Interdisciplinary studies 5.1: 131 – 135. Mbawuike, B. C. and Pepple, P. C. G. 2003. Inventory of locally available ornamental fish species in Nigerian export trade. Journal of sustainable tropical Agricultural Research 403: 1-7. McMinn, H. 1990. Effects of the nematode parasite Camallanus cotti on sexual and non‐sexual behaviours in the guppy (Poecilia reticulata). American ZoologiYst 30: 245‐249. R Measures, L. N. 1987. Epizootiology, pathology, and description of ERustrAongylides tubifex Nematoda: Dioctophymatoidea in fish. Canadian JouIrBnal of Zoology 66: 2212-2222. Measures, L.N.1988. The development of EustronYgylid e Ls tubifex Nematoda: Dioctophymatoidea in oligochaetes. Journal of Parasitology 74. 2: 294-304. Meffe, G. K. 1989. List of accepted common nameIs Tof poeciliid fishes. Ecology and evolution of livebearing fishes PoeciliidaSe. G.K. Meffe and F.F. Snelson, Jr., Eds. Englewood Cliffs, New JerseEy: RPrentice Hall. 2. 369–371. Meffe, G. K. and Snelson, F. F. Jr. 1989. Ecology and evolution of livebearing fishes (Poeciliidae). Englewood CIlifVfs, New Jersey: Prentice Hall. 453. Moorhead, J. A., and Zeng, ZN. 2010. Development of captive breeding techniques for marine ornamenta l Ufish: a review. Review in Fisheries Science, 18.4:315-343. Moravec, F. and GuNt, J. 1982. Morphology of the nematode Capillaria pterophylli Heinze, A1933, a pathogenic parasite of some aquarium fishes. Folia ParaDsitologica 29: 227–231. MoravecA, F., Jiménez-García, M.I.and Salgado-Maldonado, G. 1998a. New IBobservations on Mexiconema cichlasomae (Nematoda: Dracunculoidea) from fishes in Mexico. Parasite 5:3.289-293. Moravec, F. and Justine, J. 2006. Camallanus cotti Nematoda: Camallanidae, an introduced parasite of fishes in New Caledonia. Folia Parasitologica 53: 287- 296. Moravec, F., Kohn, A. and Fernandes, B.M. 1990. First record of Raphidascaris (Sprentascaris) hypostomi (Petter et Cassone, 1984) comb. n. and R. (S.) mahnerti (Petter et Cassone, 1984) comb. n. (Nematoda: Anisakidae) from 99 Brazil with remarks on the taxonomic status of the genus Sprentascaris Petter et Cassone, 1984. Folia Parasitologica 37:2.131-140. Moravec, F., Mendoza-Franco, E. and Vivas-Rodríguez, C. 1998b. Fish as paratenic hosts of Serpinema trispinosum (Leidy, 1852) (Nematoda: Camallanidae). Journal of Parasitology 84:2.454-456. Moravec, F. and Nagasawa, K. 1989. Observations on some nematodes parasitic in Japanese freshwater fishes. Folia Parasitologica 36: 127–141. Moravec, F., Prokopic, J. and Shlikas, A. V. 1987. The biology of nematodes of thYe family Capillariidae Neveu-Lemaire, 1936. Folia Parasitologica 34: 39-56R. Mouton, A., Basson, L., Impson, D. 2001. Health status of ornamental freshwAater fishes imported to South Africa: a pilot study. Aquatic Science RConservation. Netherlands 3: 327-333. IB Moyle, P. B. and Li, H. W. 1994. Aquatic nuisance organYism s: L setting national policy [opinion on report]. Fisheries 194: 22–23. Murray-Darling Basin Commission annual repIorTt 2005–2006. 2006. MDBC Publication no. 40/06. Murray-Darling BaSsin Commission. Canberra. Australia. Murrell, K. D., Lichtenfels, R. J., Zarlenga, RD. S. and Pozio, E. 2000. The systematics of the genus Trichinella withV a kEey to species. Veterinary Parasitology 93:293-307. I National Population CommissNion of Nigeria. (NPC). 2006 Population and Housing Census Facts aUnd Figures. Retrieved on Feb. 21, 2009 from http://www.pNopulation.gov.ng/facts and figures 2006. html. Nico, L. and FuAller, P. 2010. Pterygoplichthys disjunctivus. USGS Non indigenous AquaDtic Species Database, Gainesville, FL. Retrieved from hAttp://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=767 on July 9, 2011. rdNoIbBle, E. R. and Noble, G. A. 1971. Parasitology. The biology of Animal parasites. 3 Ed. Lea and Febiger, London. 617pp. Nordlie, F. G. 1990. Rivers and springs. In Ecosystems of Florida. R. L. Myers and J. J. Ewel. Eds. Orlando, Florida: University of Central Florida Press. pp. 392– 425. Obi, C. Potgieter, L., Bessong, N. and Matsaung G. 2002. Assessment of the microbial quality of river water sources in rural Venda communities in South Africa. Water South Africa 28: 3287-292. 100 OIE. 2003. Manual of Diagnostic Tests for Aquatic Animals. Fourth edition. Paris, Office International des Epizooties, Paris, France. 358 retrieved on September, 2010 from http://www.oie.int/eng/normes/fmanual/Asummary.htm. OIE. 2005. International Aquatic Animal Health Code. Fifth edition. Paris, Office International des Epizooties Paris, France. 176pp. retrieved on September, 2010 from http://www.oie.int/eng/normes/fcodes/Asummary.htm OIE. 2009. The OIE 5th Strategic Plan in Africa. OIE Regional Representation for Africa. Report of the 79th General Session as presented during the aRnnuYal meeting of the OIE Regional Commission for Africa May 23, 201A1in Paris, France. Retrieved on June 2, 2012 from http://www.rr- africa.oie.int/docspdf/en/2011/Strategy5af.pdf R Paperna I. 1996. Parasite, Infections and Disease of Fishes in IABfrica- An update. CIFA Technical paper 31: 1-220. L Pelicice, F. M. and Agostinho, A. A. 2005 PerspectiveTs oYn ornamental fisheries in the upper Parana River floodplain, Brazil. FisheriIes Research 72:109–119. Peters, W. C. H. 1859. Eine neue vom Herrn JaSgor im atlantischen Meere gefangene Art der Gattung Leptocephalus, uRnd über einige andere neue Fische des Zoologischen Museums. MoVnatsEberichte der Akademie der Wissenschaft zu Berlin 1859: 411-413. I Pigliucci, M. 2001. PhenotypiNc plasticity. Beyond nature and nurture. Baltimore, MD: Johns Hopkins UniUversity Press. Pigliucci, M. and MNurre n, C. J. 2003. Genetic assimilation and a possible evolutionary paradox: Acan macroevolution sometimes be so fast as to pass us by? Evolution 57.7: 1455-1464. Ploeg, AA., BDassleer, G. and Hensen, R. R. 2009. Biosecurity in the Ornamental Aquatic IBIndustry. OFI Educational publication 4, Ornamental Fish International (OFI), Fazantenkamp 5, Netherlands. Poeser, F. N. 2011. A New Species of Poecilia from Honduras (Teleostei: Poeciliidae). Copiea 3: 418 - 422. Ponpornpisit, A., Topanurak, S., Techakumphu, M. and Tangtrongpiroj, J. 2005. External Parasitic Infestation in Export Guppy Poecilia reticulata and its Quality Improvement. Proceedings of the 4th Chulalongkorn University 101 Veterinary Annual Conference. 15th February 2005. 60th Veterinary Anniversary Building, Bangkok: Chulalongkorn University. Poulin, R. 2002. Parasite manipulation of host behaviour. In The behavioural ecology of parasites, E. E. Lewis, J. F. Campbell, and M. V. K. Sukhdeo Eds. Wallingford, U.K.: CAB International. 243–257. Prang, G. 2007. An industry analysis of the freshwater ornamental fishery with particular reference to the supply of Brazilian freshwater ornamentals to the UK market. Uakari 3.1:7-51. Y Raven, P. H. and Johnson, G. B. 1996. The Origin of Life. Biology. C. J. CaroRls, K. Harris, J. E. Matthews, J. K. Banowetz, L. Hancock, L. K. WiRlson,A L.and D. thSlade. Eds. 4 Ed. Boston: McGraw-Hill Companies. 33-39. Read, A. F. 1990. Parasites and the evolution of host sexual b ehLaviIo Bur. Parasitism and Host Behaviour. C. J. Barnard and J. M. Behnke, Eds. London: Taylor and Francis. Y Rigby, M. C., Font, W. F., and Deardorff, T. L. 19I9T7. Redescription of Camallanus cotti Fujita, 1927 Nematoda: CamalSlanidae from Hawaii. Journal of Parasitology 83: 1161– 1164. R Robins, C. R. and G. C. Ray. 1986. AE field guide to Atlantic coast fishes of North America. Houghton MifflinI CVompany, Boston, U.S.A. Rosen, D. E. and Bailey, R MN. 1963. The poeciliid fishes Cyprinodontiformes, their structure, zoogeo gUraphy, and systematics. Bulletin of American Museum of Natural HistoNry 126.1:1-176. Rowland, S.J. anAd B.A. lngram. 1991. Diseases of Australian native freshwater fishes withD particular emphasis on the ectoparasite and fungal diseases of Murray cod (AMaccullochella peeli), golden perch (Macquaria ambigua), and silver perch IB(Bidyanus bidyanus). Sydney: NSW Fisheries Bulletin Number 4. Sakai, A. K.., Allendorf, F. W., Holt, J. S., Hodge, D. M., Molofsky, J., With, K. A., Baugham, S., Cabin, R. J., Cohen, J. S., Eltrand, N. C., MacCaulay, D. E., O’Neill, P., Parker, J. M., Thompson, J. N. and Weller, S. G. 2001. The population biology of invasive species. Annual Review of Ecology and Systematics 32: 305-332. Sanders, C. R. 1990. The Animal 'Other' Self Definition, Social Identity and Companion Animals. Advances in Consumer Research. M. E. Goldberg, G. 102 Gerald, and R.W. Pollay. Eds. Dulluth, Minnesota: Association for Consumer Research, 17: 662-668. Sharma, S., Jackson, D. A., Minns, C. K. and Shuter, B. J. 2007.Will northern fish populations be in hot water because of Climate change? Global Change Biology 13: 2052–2064. Shikano, T., Fujio, Y. August 1997a. Successful propagation in seawater of the guppy Poecilia reticulata with reference to high salinity tolerance birth. Fisheries Science 63.4: 573–575. Yat Shikano, T, Nakajima, M and Fujio, Y 1997b. Difference in osmoregulatory funcRtion in sea water among strains of the guppy Poecilia reticulata. FisheriRes SAcience 63: 69-72. Snieszko, S. F. 1974. The effect of environmental stress on LouItbB reak of infectious diseases of fish. Journal of Fish Biology 6: 197-208. Southgate, P. 1994. Laboratory diagnosis of fish diseasTe. InY Practice 9:252–255. Spalding, M. G., Bancroft, G. T. and D. J. FIorrester. 1993. Epizootiology of Eustrongylidosis in wading birds CiconiiSformes in Florida. Journal of Wildlife Diseases 29: 237–249. R SPSS 15.0. 2006. Statistical PackageV forE the Social Sciences. SPSS Release 15.0.0 for Windows Evaluation VersioIn 6 September, 2006. USA: SPSS Inc. Steinke, D., Zemlak, T. S. andN Hebert, P. D. N. 2009. Barcoding Nemo: DNA-Based Identifications fo rU the Ornamental Fish Trade. PLoS ONE 4:7. e6300. doi:10.1371/journal.pone.0006300 Subasinghe, R. AP., BNondad-Reantaso, M .G., McGladdery, S. E. 2001. Aquaculture development, health and wealth: The nematode Raphidascaris acus. SAubaDsinghe, R.P., Bueno, P., Phillips, M. J., Hough, C., McGladdery, S. E. Eds. IBJournal of Parasitology 82: 668-669. The United Nations Environment Programme (UNEP). 2008. Monitoring of International Trade in Ornamental Fish – Consultation Paper Prepared for European Commission Directorate General E – Environment ENV.E.2. – Development and Environment by The United Nations Environment Programme - World Conservation Monitoring Centre 219 Huntingdon Road, Cambridge CB3 0DL, UK. Retrieved Jan. 11, 2012from http://www.unep- 103 wcmc.org/medialibrary/2011/11/02/5fbf9a43/Monitoring%20of%20internationa l%20trade%20in%20ornamental%20fish%20-%20Consultation%20Paper.pdf. Theron, J. 2001. The challenge of identifying water borne pathogen leads to new technology. Water South Africa bulletin 27310-13. Thilakaratne, I. P., Rajapaksha G., Hewakopara A., Rajapakse R. P. and Faizal, A. C. 2003. Parasitic infections in freshwater ornamental fish in Sri Lanka. Diseases of Aquatic Organisms 54: 157–162. Thomas, F., Adamo, S., and Moore, J. 2005. Parasitic manipulation: where are we anYd where should we go? Behavioral Processes 68: 185–199. R Thunberg, E. M., J.T. Rodrick, J. T., Adams, C. M. and Chapman, F. W. 199A3. Trends in United States International Trade in Ornamental FishR, 1982-1992. International Working Series. Paper IW-93-19. Gainesville :I FBood and Resource Economics Department. University of Florida. 58. L Toft, C. A. 1986. Parasites etc. Community Ecology, JT.N. YDiamond and T.J. Case, Eds. New York: Harper and Row. 445 - 463. I USDA/APHIS. 2008. Overview of AquaculturSe in the United States. Centers for Epidemiology & Animal Health USDRA:APHIS:VS. Colorado. Retrieved Jan. 7, 2011 E from http://www.aphis.usda.gov/IanVimal_health/nahms/aquaculture/downloads/Aquac ultureOverview95.pdf. N Vitousek, P. M.., Moon eyU, H. A.., Lubchenko, J. and Melillo, J. M. 1997. Human domination of Earth's ecosystems. Science 277: 494–499. Wabnitz, C., TayAlor,N M. and Green, E. 2003. From Ocean to Aquarium. Cambridge, UK: UNEP-WCMC. WallaceA, HD.R. 1961. The bionomics of the free-living stages of zoo-parasitic IBnematodes: A critical survey. Helminth Abstracts. 30.1. Warren, C.E. 1971. Biology and water pollution control. W.B. Saunders, Philadelphia, Pennsylvania. USA. Waters, T. F. 1995. Sediment in streams: Sources, biological effects, and control. American Fisheries Society Monograph Bethesda, Maryland, 7:251. Webb, A. C., Maughan, M. and Knott M. 2007. Pest fish profiles Trichogaster trichopterus - The three spot gourami. Australian Centre for Tropical Freshwater Research ACTFR, James Cook University, 1-5. 104 Welcomme, R. L. 1988. International introductions of inland aquatic species. Food and Agriculture Organization of the United Nations. FAO Fish Technical paper 294:318. Wetzel, R. G. 1983. Limnology. Harcourt Brace Jovanovich Publishers, Inc., New York, New York. Whitfield, P. J. 1979. The biology of parasitism: an introduction to the study of associating organisms. Contemporary Biology Series. E. J. W, Barrington., A. J, Willis. and M. A. Sleigh. Eds. London: Edward Arnold. 277. Y Whittington, R. J. and Chong, R. 2007. Global trade in ornamental fishA froRm an Australian perspective: The case for revised import risk analysis and management strategies. Previews of Veterinary Medicine. RetrieRved on March 2, 2008 from http://www.citeulike.org/user/sarahferriss/articIleB/1296825. Williams, H. and Jones, A. 1994. Parasitic worms of FishY. Lo nd Lon: Taylor and Francis Ltd. Willmott, S. and Chabaud, A. G. 1974. GeneraIl Tintroduction. CIH keys to the nematode parasites of vertebrates. AndSerson, R. C., Chabaud, A. G. and Willmott, S. Eds. No.1, Farnham RRoyal, Bucks, England. Commonwealth Agricultural Bureaux No. 1.6: 11E8. World Resources Institute. 2002. TIhVe United States consumption of ornamental fish: a preliminary analysis oNf import data . World Resources Institute NOAA Final Report. 47. U Yacoub, R. S., Salem, G . H., Nessiem, M. G. and Siam, M. A. 1993. The possible role of non-spAecifNic hosts (Chickens and Rabbits) in the epidemiology of Trichinella spiraDlis. Journal of Veterinary Medicine, Giza. 47:27-31. YamaguAti, S. 1961. Systema Helminthum. Vol. III. The nematodes of Vertebrates. New IBYork, Interscience Publishers Ltd. John Wiley and Sons, New York. 1261pp. Zion, B., Alchanatis, V., Ostrovsky, V., Barki, A. and Karplus, I. 2008. Classification of guppies’(Poecilia reticulata) gender by computer vision. Aquacultural Engineering 38.2: 97-104. 105 APPENDIX 1 Y RA R LIB ITY RS VEI a N U DA N A WIhiBte Egrets (a), Ardea alba, occasional visitors to a failed section of drain on Basil Ogamba Street. 106 APPENDIX 2 RY a RA LIB b TY RS I VE NI U An occluding wastewNater drain on Ahmadu Bello Road in June, 2004 with (a) gradual loss of habitat toA wastewater fauna including P. reticulata and (b) fully blocked section. AD IB 107 APPENDIX 3 Correlation co-efficient of Nematode parasite prevalence in P. reticulata obtained from Igi-Olugbin Street in relation to the means of monthly physicochemical parametRers oYf wastewater in drains. RA LIB TY SI Temperature (OC) 1.0 R Ph 0.4 1.0 E Dissolved Oxygen(mg/L) -0.4 I0V.2 1.0 Transparency (cm)U -0N.5 -0.3 -0.1 1.0 Drain Depth (cm) -0.4 0.0 0.6 -0.1 1.0 N E. ignotus 0.5 -0.1 -0.5 0.0 -0.2 1.0 TrichiAnella spp. -0.2 -0.4 0.1 -0.3 0.2 0.2 1.0 D C. pterophylli 0.1 -0.1 0.0 -0.3 0.6* 0.2 -0.1 1.0 A C. cotti 0.2 0.7* 0.0 -0.2 0.4 0.1 -0.3 0.4 1.0 I B 108 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 4. Correlation co-efficient of Nematode parasite prevalence in P. reticulata obtained froYm Basil Ogamba Street in relation to the means of monthly physicochemical paramReters of wastewater in drains. RA LI B SI TY Temperature (OC) 1.0 R pH 0.6 1.0 E Dissolved Oxygen (mg/L) 0.3 IV0.0 1.0 Transparency (cm) 0N.0 -0.1 0.3 1.0 Drain Depth (cm )U 0.0 -0.3 0.5 0.0 1.0 E. igNnotus 0.3 0.4 0.0 -0.3 0.0 1.0 A Trichinella spp. 0.3 0.2 0.0 -0.2 0.2 0.9 1.0 D C. pterophylli 0.6 0.5 0.0 -0.1 -0.1 -0.2 -0.1 1.0 A C. cotti 0.4 0.2 0.1 -0.3 0.3 0.9 1.0 -0.2 1.0 IB 109 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 5 Correlation co-efficient of Nematode parasite prevalence in P. reticulata obtained froYm Ahmadu Bello Road in relation to the means of monthly physicochemical paramReters of wastewater in drains. A LIB R ITY RS Temperature (OC) 1.0 IV E pH -0N.5 1.0 Dissolved Oxygen (mg/L) U-0.2 0.1 1.0 Transparency (cm ) -0.2 0.3 0.4 1.0 Drain DepthN (cm) 0.6 0.1 -0.5 -0.4 1.0 A E. ignotus 0.2 -0.1 -0.4 -0.3 0.5 1.0 D Trichinella spp. 0.0 -0.1 0.3 -0.1 0.1 0.2 1.0 A C. pterophylli 0.3 -0.3 -0.4 -0.2 0.2 0.7 0.3 1.0 IB C. cotti 0.3 -0.3 0.5 0.3 -0.1 0.2 0.0 0.1 1.0 110 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 6. Correlation co-efficient of Nematode parasite prevalence in P. reticulata obtained from Adenaike Alagbe Street in relation to the means of monthly physicochemicYal parameters of wastewater in drains. AR R LI B SI TY Temperature (OC) 1.0 ERV pH -0.1 1.0 Dissolved Oxygen (mg/L) -0.3 I 0.1 1.0 Transparency (cm) -N0.6 0.0 0.3 1.0 Drain Depth (cm U) 0.0 -0.1 0.5 0.3 1.0 N E. ignotus -0.1 -0.3 0.2 -0.1 0.6 1.0 TrichAinella spp. -0.2 0.1 0.8 0.4 0.4 0.0 1.0 D C. pterophylli -0.6 0.3 0.1 0.5 0.3 0.3 -0.1 1.0 A C. cotti 0.3 0.6 -0.1 -0.2 0.1 0.0 -0.1 0.0 1.0 IB 111 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 7 Correlation of Mean intensity of nematode parasites in P. reticulata obtained from IgYi- Olugbin Street in relation to means of monthly physicochemical parameteRrs of wastewater in drains. RA LI B ITY Temperature (OC) 1.0 S R pH 0.4 1.0 E Dissolved Oxygen -0.4 IV0.2 1.0 (mg/L) Transparency (cm) -0N.5 -0.3 -0.1 1.0 Drain DepthN (cm ) U-0.4 0.0 0.6 -0.1 1.0 E. ignotus 0.4 0.4 0.0 0.0 0.2 1.0 TDrichAinella spp -0.1 -0.4 -0.3 0.1 0.1 0.0 1.0 AC. pterophylli 0.0 -0.2 0.2 -0.3 0.6 0.2 0.7 1.0 B C. cotti 0.3 0.4 0.0 -0.2 0.2 0.7 0.2 0.4 1.0 I 112 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 8 Correlation of Mean intensity of nematode parasites in P. reticulata obtained froYm Basil Ogamba Street in relation to means of monthly physicochemical paraAmetRers of wastewater in drains. LIB R ITY RS Temperature (OC) 1.0 E pH N0.6 I V1.0 Dissolved Oxygen U 0.3 0.0 1.0 (mg/L) TransparencNy (cm) 0.0 -0.1 0.3 1.0 A Drain Depth (cm) 0.0 -0.3 0.5 0.0 1.0 D E. ignotus -0.1 0.4 -0.3 -0.2 -0.4 1.0 A Trichinella spp. 0.3 0.1 0.2 0.0 0.3 0.0 1.0 IB C. pterophylli 0.4 0.3 -0.1 -0.2 0.2 -0.1 -0.2 1.0 C. cotti 0.2 -0.2 0.4 -0.4 0.3 -0.1 0.0 -0.2 1.0 113 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 9 Y Correlation of mean intensity of nematode parasites in P. reticulata obtainedR from Ahmadu Bello Road in relation to means of monthly physicochemical wastewater in drains. BR paraAmeters of Y LI T RS I Temperature (OC) 1.0 VEI pH -N0.5 1.0 Dissolved OxygenU -0.2 0.1 1.0 (mg/L) TransparencNy (cm) -0.2 0.3 0.4 1.0 A Drain Depth (cm) 0.6 0.1 -0.5 -0.4 1.0 D E. ignotus 0.0 0.2 0.0 -0.2 0.5 1.0 A Trichinella spp. 0.1 -0.2 -0.3 -0.2 0.4 0.2 1.0 IB C. pterophylli -0.2 0.5 -0.1 0.4 0.0 0.1 0.2 1.0 C. cotti 0.0 -0.2 0.5 0.0 -0.2 -0.1 0.4 -0.2 1.0 114 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti APPENDIX 10 Correlation of mean intensity of nematode parasites in P. reticulata obtained from Adenaike Alagbe Street in relation to means of monthly physicochemical parameters oYf wastewater in drains. RA R LIB ITY Temperature (OC) 1.0 S R pH -0.1 1.0 VE Dissolved Oxygen -0.3 I 0.1 1.0 (mg/L) Transparency (cm) -N0.6 0.0 0.3 1.0 Drain Depth (cm U) 0.0 -0.1 0.5 0.3 1.0 E. iNgnotus 0.1 0.2 -0.1 -0.4 -0.4 1.0 TrichAinella spp. 0.3 -0.2 0.6 0.0 0.2 0.2 1.0 D C. pterophylli 0.4 0.0 0.1 -0.3 -0.2 0.5 0.8 1.0 A C. cotti 0.5 -0.6 0.0 -0.4 0.3 0.2 0.5 0.5 1.0 IB 115 Temperature (OC) PH Dissolved Oxygen (mg/L) Transparency (cm) Drain Depth (cm) Eustrongylides ignotus Trichinella spp. Capillaria pterophylli Camallanus cotti