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MOLECULAR ANALYSIS OF MECHANISMS AND IDENTIFICATION OF FACTORS OF PYRETHROID RESISTANCE IN ANOPHELES GAMBIAE SENSU LATO IN SOUTHWESTERN NIGERIA AND SOUTHERN BENIN REPUBLIC
(201) DJOUAKA-FOLEFACK, J. R.
The development of resistance to insecticides by Anopheles mosquitoes continues to threaten the success of malaria control programmes in West Africa. Local data on mechanisms and factors causing resistance in the region are scanty. This study was designed to investigate the environmental factors and mechanisms implicated in resistance to pyrethroids by Anopheles gambiae in southwestern Nigeria and southern Benin Republic. Larvae of Anopheles mosquito were collected in 2007 from 19 localities in the six states of southwestern Nigeria and 18 localities in the seven divisions of southern Benin and reared to adults. These were identified morphologically and with Polymerase Chain Reactions (PCR). They were also bioassayed for susceptibility to pyrethroids. Molecular characterisation of pyrethroid resistant phenotypes was carried out using PCR and microarray analyses of the expressed genes. Dissolved Oxygen (DO) and pH were determined using a digital multipurpose meter while physical appearances of breeding sites were assessed visually. Xenobiotic factors such as Spilled Engine Oil (SEO) and agricultural pesticides that might contribute to the emergence of resistance in Anopheles populations were examined through bioassay. Associations between pyrethroid resistance with environmental factors and molecular profiles of Anopheles were evaluated using Chi square. A. gambiae complex genotyped in Nigeria comprised of 73.6 % A. arabiensis and 26.3 % A. gambiae sensu stricto; while those genotyped in Benin were 92.9 % A. gambiae s.s. and 7.0 % A. melas. Pyrethroid resistance in Nigeria and Benin were recorded in 68.4 % and 94.4 % of the localities examined respectively. Breeding sites contaminated with SEO (B-SEO) or Pesticide Residues (B-PR) had low DO (B-SEO = 13.4 ± 1.5 mg/l, B-PR=12.2 ± 1.7 mg/l), the Non-contaminated Breeding sites (B-NC) had higher levels of DO (B-NC=33.1 ± 2.3) and mainly produced pyrethroid-susceptible Anopheles (p<0.05). Significant variations in pH were not recorded. Differences in habitation by resistant-Anopheles in breeding sites contaminated with SEO or pesticide residues were observed. A. gambiae found around the two agricultural sites (Houeyiho, Benin and Ajibode, Nigeria) exposed to synthetic pesticides showed significant levels of pyrethroid resistance with mortality rates of 70.0 % and 89.7% respectively. A. gambiae larvae survived at SEO concentrations below 11.8x10-3 μL/cm2. Ninety six percent of larval mortality resulted from direct cuticle contact with SEO whereas only four percentage mortality was from larval suffocation. A cross resistance phenomenon was recorded with SEO and pyrethroids. A. gambiae showed the presence of elevated frequencies of knock down resistance West (kdr-W) mutations in Benin samples (kdr-W ranged from 0.6 to 0.9) and absence of kdr-W in Nigeria samples. Two detoxification genes (CYP6P3 and CYP6M2) were up-regulated in resistant-Anopheles. Additional detoxification genes specific to agricultural and SEO sites were also over-expressed in the resistant populations. There was an association between residual synthetic pesticides, spilled engine oil and emergence of pyrethroid-resistance in A. gambiae in Nigeria and Benin Republic. The diversified profile of identified metabolic genes reflected the influence of a range of xenobiotics on selection of resistance in mosquitoes.
An evaluation of the prevalence and intensity of liver fluke infection in cattle slaughtered in Jos abattoir with comments on the incidence of amphistome infection
(1986) Okwuosu, V. N.; Ariyo, S. A.
An evaluation of the prevalence of liver fluke disease of cattle revealed an upward trend for an urban abattoir. A total of 3072 animal gall bladders were assayed between December 1980 and January 1982 and 74.06 + 6.46% were positive, the major fluke species were Fasciola gigantic and diocrocoellum hospes with a few case of schistosoma bovis. The max/min. monthly prevalence rates were 85.42% and 60.00% respectively. The mean rates for D. hospes and F. gigantic were 57.95 + 6.58% nd 48.71 + 11.66% respectively. T-test assessments showed these mean to be significantly different. The study further showed that for natural infections of cattle mixed infections were more frequent than singe infections. The mean value were 32.13% as against X single infection rates of 25.5% and 16.45% for D. hospes and F. gigantic. Chi-square analysis confirmed that mixed infection rates were significantly higher than single infections for both species. The flike species were highly prolific, producing mac egg count of 50 x 103 and 60 x 103 c.p.ml for F. gigantic and D. hospes respectively. There was variation in egg count due to seasons with significantly more eggs produced in the dry than in the wet season, for freely infected animals, there wa suppression of egg production in mixed infections which though affecting the species, had more effect on F gigantic, this resulted in significantly more eggs being produces by either species in single than in mixed infections
Effect of ultraviolet radiation on survival, infectivity and maturation of schistosoma mansonicer cariae
(Australian Society for Parasitology, 1990) Ariyo, A. A.; Oyerinde, J. P. O.
S. mansoni cercariae exposed to ultraviolet radiation for 1,3, 5,10 and 20 s as well as non-irradiated cercariae remained actively motile 30 min post-irradiation. Thereafter the activity decreased with increasing dose level of radiation and age of cercariae. There was no significant difference between the rates of attachment of the batches of cercariae. The recovery rates (0-49% of cercariae to which mice were exposed) of adult worms were, however, significantly different from the number of cercariae calculated to have attached to the mice (93.5-100% of cercariae to which mice were exposed). Maturation and penetration rates were dependent on radiation exposure levels. Numbers of eggs deposited in the liver of mice as well as hatchability rate of eggs varied significantly with the levels of exposure to radiation
REPRODUCTION, LARVAL REARING AND THE INFLUENCE OF DIETARY PROTEIN LEVELS ON THE GROWTH OF THE CATFISH CHRYSICHTHYS NIGRODIGITATUS (LACEPEDE)
(1992) ABOABA, M. A.
Reproduction and early development were studied in the catfish Chrysichthys nigrodigitatus (Lacepede). From the monthly analysis of gonado-somat ic indices it was shown that the species had an annual reproductive cycle that falls into four distinct phases. The gonad preparatory phase was observed between September and December, the prespawning or maturing phase was between January and February, the spawning phase was in March and Apri1 and possib1y May, whi1e the resting phase occurred during June to August. In the males, two distinct reproductive phases were indicated. These were the gonad preparatory phase or growth phase which occurred between July and February, and the spawning phase which occurred during March to May. C. nigrodigitatus was observed to store up lipids in its muscle and liver during the initial period of gonadal growth. The lipids were later utilized for gonadal maturation, spawning activities and parental care. Observed environmental features coinciding with spawn1ng 1n sexually mature individuals in Asejire lake included low water level, presence of suitable spawning substrate, direct contact with mature partner in the absence of light and a gentle flow of water across the spawning substrate. In the presence of these features, spawning occurred within 48 hours when gravid male and female were paired in Asejire lake. The fertilized eggs from the Asejire stock hatched in the laboratory between 48 and 50 hours. The development and growth of the early larvae are described. Results of two weeks of exogenous feeding trials showed that the larvae of C. nigrodigitatus fed on live plankton had specific growth rate of 13.24 and 26% survival while those fed on 40% crude protein level had specific growth rate of 1.46 and 2% survival. Larvae fed on 35% and 30% dietary crude protein levels survived for only 5 days. Effects of different levels of crude protein diets fed to fingerlings, juvenile fish and adults of both sexes were evaluated. It was found that the fingerlings and juvenile fish had best growth in the diet containing 35% crude protein. The male and female adults had best growth on 25% and 35% crude protein respectively. Results of carcass analysis showed that the percentage of body fat increased significantly (p < 0.05) with increasing dietary protein levels while there was no significant (p>0.05) increase in the percentage of body protein. This suggests that the weight gain in the fish resulted from fat deposition. The general increase in the percentage of body fat of the adult fish compared with that of the young fish further confirm that fat deposition is an essential energy reserve in preparation for-breeding season.
Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum
(The American Society of Tropical Medicine and Hygiene, 1998) Nwagwu, M.; Anumudu, C. I.; Sodeinde, O.; Ologunde, C. A.; Obi, T. U.; Wirtz, R. A.; Gordon, D. M.; Lyon, J. A.
Collections of human sera from malaria-endemic areas would be valuable for identifying and characterizing antigens as malaria vaccine candidates if the contributing serum donors’ ability to resist infection were fully characterized. We prepared such a serum collection from 26 apparently immune Nigerian adults who failed to develop patent parasitemia for at least 20 weeks following a documented increase in antibodies to the circumsporozoite protein (CSP) from Plasmodium falciparum. Volunteers were evaluated five times per week for malaria symptoms and bimonthly for parasites by examining thick blood smears. The incidence rate over 13 months for the cohort was 42% (47 malaria-confirmed volunteers) and the risk of infection was 1.3 infections/year. Responses to CSP did not correlate with protection. Because antibody responses to antigens other than CSP may be associated with protection, the sera from these immune individuals may be useful for identifying and characterizing other potential malaria vaccine candidates.
Ultraviolet radiation of schistosoma mansoni. I. influence of pre-hatching radiation of eggs on hatchability of eggs and survival of miracidia
(2000) Hassan, A. A.; Oyerinde, J. P. O.
The hatchability of Schistosoma mansoni' eggs exposed to ultraviolet (UV) radiation and the activity of die hatched miracidia were examined. Hatchability decreased with die increasing exposure to irradiation. The difference in hatchability of eggs irradiated for 15 and 30 minutes were highly significant (P < 0.01. dα = 3.07 and 3.24) compared with hatchability of the non-irradiated eggs. The mean motility rates of the hatched m iracidia were found to be radiation dose-dependent. There was a 21.4% reduction in motility compared with die motility rates in the non-irradiated miracidia. The life span of irradiated miracidia was shortened, only 19% of dtose exposed to UV radiation for 30 minutes survived for 3 hours as against 80% survival rate in die non-irradiated miracidia. There was no significant difference found in the ability of hatched miracidia to attach to the snails irrespective of the radiation dose exposure the eggs were initially subjected
Occurrence and distribution of rhabditis axei (rhabditida; rhabditidae) in African giant snails in southwestern Nigeria
(De Gruyter Open Ltd., 2000) Odaibo, A. B.; Dehinbo, A. J.; Olofintoye, L. K.; Falode, O. A.
African giant snails (Archachatina marginata ovum Pfeffer, 1858; A. marginata saturalis Philippi, 1849 and Achatina achatina Linne, 1758) were examined for the occurrence of Rhabditis axei Cobbold. 1884.Differences in parasite intensity between size groups of snails were highly significant (P < 0.05) for die 3 species compared. The mean egg and larval output per gram of faeces was higher in larger snails. The mean intensity of the nematode eggs excreted was higher (P < 0.05 ) than the mean of larval output for the 3 species of snails. The distribution of R. axei within the snail hosts revealed site preferences. They are mostly (88 %) located in the rectum of the snails.
Evaluation of a rapid immunochromatographic card test for Plasmodium falciparum in Ibadan, Nigeria
(College of Medicine, University of Ibadan and the University College Hospital, 2001) Nwuba, R. I.; Anumudu, C. I.; Omosun, Y. O.; Sodeinde, O.; Nwagwu, M.
This short report describes the results of a rapid; simple and cost effective immunodiagnostic test for malaria in Ibadan, Nigeria. A total of 77% patients presenting at the children outpatient clinic, University College Hospital with malaria symptoms were screened for malaria parasites by microscopy using Giemsa stain and by the immunochromatographic card test. The immunodiagnostic test had a sensitivity of 93.1 % and a specificity of 95.8%, making a good alternative for malaria diagnosis especially in rural areas without electricity, where microscopy is not possible, and a decision is to be made on when to start treatment.
Attitudes and practices towards abate application in a village in Akinyele local government area of Oyo State, Nigeria
(Klobex Academic Publishers, 2001-09) Falode, O. A.; Odaibo, A. B.
A study was carried out in Oyeteju Village in Akinyele Local Government Area of Oyo State to determine attitudes of the villagers to treating their drinking pond with Abate (Temephos). The findings showed that all women respondents fetched all their drinking water from the village pond. They all claimed to filter the drinking water, 83.3% claimed to add alum while 25% claimed to boil water. Only 75% knew why Abate was applied to pond despite previous education on Abate. 41.7% support Abate application because it will kill the guineaworm 'germs’ in water while 25% Support it because it will bring about good health to villagers. All the respondents claimed not to be affected by the application of Abate to pond water despite the fact that 33.3% said the pond water turned black while 8.3% said it turned reddish. Their strong belief in their pond which is their god and the colour change did not make the villagers go against the application of Abate to their pond. This was so because health education on Abate preceded its application. It was unfortunate however that the Abate application was not sustained in the village. Abate application in this village was accepted as a temporary measure while villagers wait expectantly for their own safe source of water preferably a borehole. The study shows the need for health education to proceed the application of Abate and the need to train villagers on how to apply the Chemical in order to sustain the application for effective control.
Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) ability to breed and damage potential on cassava dried chips
(Klobex Academic Publishers, 2001-12) Hassan, A. T.; Popoola, K. O. K.
Stored dried cassava chips are known to become heavily damaged by Prostephanus truncatus (Hum). A laboratory study was undertaken to determine the extent of losses that this insect pest could cause on TME 30572, the mean weight loss (±SD) rose to 36.93 ± 24.43% over the period of 112 days compared with 63.2 ± 3.37% for TME 1, under the same period and experimental condition, At each time interval of 28 days during which the cassava dried chips were examined, the weight loss in both varieties was on the increase, except, the 112 days where their was a drop in the weight loss in TME 30275 variety which was statistically significantly (t=0.033, P<0.05). Percentage mortality rate rose from 0% to 10.6% in TME 30572 larval, while zero mortality was recorded for TMEI larval. On the other hand, percentage mortality was on the increase in emergent adults for both cassava varieties. The highest percentage mortality in TME1 emergent adult was inflicted in TME1. However, storing TME 30572 rather than TME1 will not solve the problem of infestation and damage by P. truncatus because considerable damage is been inflicted on TME 30572. The experiment was conducted under ambient temperature of 30.3 ± 3.7°C and relative humidity of 84.7 ± 2.0% in the laboratory.
Management and attitudes of villagers towards boreholes in guineawarm eradication in Akinyele local government Area of Oyo State, Nigeria
(2002) Falode, O. A.; Odaibo, A. B.
Studies on the management and attitudes of villagers to boreholes as a source of water in guineaworm eradication was carried out in 4 villages, Alagba, Deinlokun, Iware and Idi-omo in Akinyele Local Government Area of Oyo State, Nigeria.The findings showed that the borehole reduced or eradicated the guineawonn disease in villages studied but its reliability and efficiency was threatened by insufficient borehole water (especially in villages with a population exceeding 500) and lack of a maintenance schedule by the local government area. It was concluded that it is necessary to carefully consider the reliability of the borehole and the size and the distribution of the population they will serve before they are constructed, in order that the full benefit of water supply intervention can be achieved
Specificities of antibodies to Plasmodium falciparum merozoite surface protein (MSP)-1 19
(2002) Nwuba, R. I.; Adoro, S. A.; Anumudu, C. I.; Odaibo, A. B.; Omosun, Y.; Holder, A. A.; Nwagwu, M.
In a survey of children living in South Western Nigeria, plasma levels of anti-MSP119 antibodies were not associated with patent parasitemia. Anti-MSP119 antibody titres correlated positively with age, indicating that development of antibodies to MSP119 may depend on long-term exposure to parasites. Using competitive ELISA, 82% of the samples inhibited the binding of processing-inhibitory monoclonal antibodies (mAb) 12.8 and 12.10 to immobilized recombinant MSP119. The binding of mAb 12.8 in the presence of 18% of these samples .was reduced to less than 10%. This suggest that these samples contain polyc1onal antibodies that have a similar binding specificity to that of mAb 12..S, which recognizes an epitope located in the first epidermal growth factor domain of MSP119. Our data provide useful leads for the design of an MSP119-based vaccine.
Soil faecal pollution and the risk of hookworm infection in areas of Ibadan, Nigeria
(2002) Hassan, A. A.; Shittu, M. O.
Soil samples were randomly collected from 25 different observed and suspected human communal defecation locations within Ibadan. All the soil types encountered namely, sand, sandy loam, Sandy, clay loamy, and loamy sand enhanced hookworm larval propagation. The organic matter content showed a decrease with depth. The surface layer soil samples supported hookworm larval growth while the sub soil layer with the same amount of organic matter content as the surface soil layers showed a net zero larval growth. The overall average of 11 x 103 hookworm larvae per gram of soil sample showed a high level of hookworm infestation of the soil. The assessment of food vendor trainee revealed a 36% hookworm infection out of which 80% had low level of awareness of hookworm disease. Furthermore, 75% had no knowledge of transmission of the disease and no evidence of toilet facility was found in their homes. The lack of standard public toilets where they are available at all and lack of knowledge of hookworm disease have contributed to the complexity of the problem of possible spread of hookworm infection in the study area
Cyclopoid copepods in domestic water sources in three villages in Akinyele local government area of Oyo State, Nigeria
(2002) Falode, O. A.; Odaibo, A. B.
The distribution and infective rates of cyclopoid copepods ( the vectors of guineaworm, Dracunculus medinensis ) in ponds was studied in 3 infected villages in Akinyele Local Government Area of Oyo state, Nigeria during the period of September 1994 to January 1996 (the peak period of guineaworm eradication activities in the country). The density of cyclopoid copepods was highest in the dry season, reaching 149.8 copepods/litre in February 1995. The abate (Temephos) application and amount of rainfall affected the cyclops in ponds. Thermocyclops, Mesocyclops and Halicyclops species of cyclops were recovered from the ponds while none was found to be infected with D.medinensis larvae.
Studies on the lifecyc1e of aleurodicus dispersus (rusell) (homoptera: aleyrodidae) on potted cassava plant in a screen house
(Klobex Academic Publishers, 2002) Popoola, K. O. K.; Hassan, A. T.
The life cycle, and morphometries studies of A. dispersus (Rusell), white flies were conducted in a screen house in the Department of Zoology, University of Ibadan, Ibadan. The study revealed that A. disperses (Rusell) on cassava potted plants leaves, Manihot esculenta (Cranzt) (TMS 91934), have six stages, which include, egg first instar, secxond instar, third instar, pupa and adult. Trichoderma lignorum a fungal was identified as the cause of high mortality rate which occurred on the eggs and the intars of A. dispersus. The study was carried out under varied temperature and relative humidity of (27.20 - 30.33°C) and 68.00 - 82.33%) respectively for a period of 29 days.
The human immune response to Plasmodium falciparum includes both antibodies that inhibit merozoite surface protein 1 secondary processing and blocking antibodies
(American Society for Microbiology, 2002-09) Nwuba, R. I.; Sodeinde, O.; Anumudu, C. I.; Omosun, Y. O.; Odaibo, A. B.; Holder, A. A.; Nwagwu, M.
Malaria merozoite surface protein 1 (MSP1) is cleaved in an essential step during erythrocyte invasion. The responses of children to natural malaria infection included antibodies that inhibit this cleavage and others that block the binding of these inhibitory antibodies. There was no correlation between the titer of the antibody to the 19-kDa fragment of MSP1 and its inhibitory activity. These findings have implications for the design of MSP1-based vaccines.
Poverty and HIV/AIDS patient management in Swaziland: a case study of known HIV/AIDS patients
(Africa Institute of South Africa & SAUSSC., 2003) Owumi, B. E.; Ezeogu, A
Clinical manifestations and immune response to MSP 119 in severe paediatric malaria in Adeoyo state maternity hospital, Ibadan
(College of Medicine, University of Ibadan and the University College Hospital, 2004) Anumudu, C. I.; Okafor, C. M. F.; Ngwumohaike, V.; Afolabi, K. A.; Nwuba, R. I.; Nwagwu, M.
A 10-week cross-sectional study was carried out at the Adeoyo State Maternity Hospital (Beere, Ibadan), Southwestern Nigeria in order to determine (a) the prevalence of severe malaria, (b) identify the predominant clinical presentations that characterise the disease in children below 5 years and the pattern of antibody responses to MSP 119 elicited in severe malaria complications. Three thousand, one hundred and thirty-one cases reported to the Out Patients' Department; of these, 372 (11.8%) subjects were recruited on the basis of doctors' diagnosis of severe malaria, malaria and other complications. Six per cent (188/3131) of the patients were admitted. Serum samples for 320 of the 372 subjects were analysed for antibodies specific to MSP 119 by ELISA. The highest antibody responses occurred in the age group 2-5 years. Parasite prevalence was 77.9% (290 of 372 subjects) and parasite density ranged from 80 to >100000 parasites/uL blood. Fever (an average temperature of 38.6 ±0.4°C and peak at 41°C) and severe malaria were the major clinical manifestations of rnalaria amongst the study population. Severe malaria was found to be associated with other features such as cough, vomiting and diarrhoea.
Clinical malaria diagnosis in adults: the value of signs symptoms and antibodies
(College of Medical Sciences, University of Benin, 2004-12) Anumudu, C. .; Ukoha, U.; Nwuba, R. I.; Nwagwu, M.
In the absence of microscopic examination, the high prevalence of asymptomatic malaria infections and the non-specific symptoms of the disease make clinical diagnosis difficult in highly endemic areas. Data from daily medical records 0f 111 adult volunteers obtained in a 13-month longitudinal survey were analysed using Pearson's correlation to investigate the relationship between parasitaernia and clinical symptoms and to determine the predictive strength of various clinical symptoms for malaria. Forty three percent of the subjects were blood smear positive at one or more times in the study. Parasite prevalence and clinical symptoms followed a seasonal distribution, being higher and occurring more often in the high transmission periods. High antibody responders to the circumsporozoite protein (CSP) showed lower parasite prevalence and fewer symptoms compared to the other responders. Malaria parasitaemia was significantly correlated with fever (p < 0.01). Fever, joint pain and headaches could be useful in endemic areas as symptom indicators of malaria for adults.
Spatial variation in physical and chemical parameters and benthic macro-invertebrate fauna of River Ogunpa, Ibadan
(2005) Atobatele, O. E.; Morenikeji, O. A.; Ugwumba, O. A.
A fluviatile ecosystem, River Ogunpa, was studied between the months of May and July 2000, to assess spatial variations in physical and chemical parameters and benthic macro-invertebrate faunal composition. Water and qualitative benthic samples were collected four times from five stations located along the river for laboratory analysis. High mean value of biochemical oxygen demand (BOD) of 20.15 ± 4.18 mgO2/l, chemical oxygen demand (COD) of 121.95 ± 19.04 mg02/l ammonia of 1.53 ± 0.44mg/l, total suspended solids (TSS) of 152.2+12.85mg/l, lead of 0.126 ± 0.06mg/l, copper of 0.3+0.07mg/l and zinc of 0.49 ± 0.07mg/l were recorded. Analysis of variance (ANOVA) showed significant differences (P<0.05) in mean values of pH, dissolved oxygen (DO), COD, turbidity, iron and copper from the five stations. Six benthic macroinvertebrate fauna; Melanoides tuberculata, Physa waterloti, Bulinus globosus, Tubifex spp; Chironomus spp and Brachydeutera spp. were recorded. The result showed that the river is under pollutional stress from oxygen demanding organic wastes. Heavy metals analyzed show that lead, copper and zinc levels may be increasing to dangerous levels in the river. Spatial variations along the river showed some stations to be more polluted than others. All the benthic macro-invertebrate fauna recorded were pollution tolerant species.