Trap. Vet. 17, 45-50 (1999) Newcastle Disease, Infectious Bursal Disease and EDS ’76 Antibodies in Indigenous Nigerian Local Chickens O.A. ADEDOKUN and O.A. DUROJAIYE Department o f Veterinary Microbiology and Parasitology, University o f Ibadan, Ibadan. Nigeria. Key Words: Newcastle disease, infectious bursal disease, EDS ’76, serology, Nigerian indigenous chickens. Abstract A serological survey was conducted to determine the prevalence of Newcastle disease (ND), infectious bursal disease (IBD) and egg drop syndrome ’76 (EDS ’76) antibodies in indigenous Nigerian local chickens. The survey was carried out in Ekiti, Osun, Oyo, Ogun and Lagos States in southwestern Nigeria. Out o f 2010 serum samples assayed for ND, 1890 (94%) were positive. 720 (34%) out of 2090 samples were positive for IBD, while 500 (29%) out of 1740 samples were positive for EDS ’76. The prevalent rates are high enough to suggest that ND, IBD and EDS ’76 are still very active in these indigenous chickens. The implications of these findings in the control of ND, IBD and EDS ’76 in the commercial exotic poultry flocks are discussed. Introduction poultry by a ratio of 8:1 and they constitute the true poultry to over 70% of Nigerians. According to Akiinvumi et al. (1979), He further stated.that an extra dimension to there are about 134 million chickens in the findings on poultry disease pathotypes in Nigeria of which 124 .millions are Nigeria and most other developing countries, indigenous local chickdns. These indigenous is the’involvement of village chickens in the chickens are reared under relatively epidemiology of poultry' diseases. uncontrolled extensive system of Some of the infectious diseases of management, such that their proximity to commercial poultry' identified in Nigeria are and actual contact with exotic commercial Newcastle disease (ND) (Hill et a/., 1953), poultry' strongly suggest that they could play . infectious bursal disease (IBD) (Ojo et al., a role in the transmission of infectious 1973), and egg drop syndrome ’76 (EDS diseases of poultry'. This observation has ’76) (Nawathe and Abegunde, 1980). been made by Adene et al. (1985) and also All ages of birds of different species are on Marek’s disease (Adene, 1983). Adene susceptible to ND. The acute and virulent (1997) stated that in Nigeria, the indigenous form may result in mortality of up to 90% (rural) poultry outnumber the commercial or more in affected flock with heavy' loses UNIVERSITY OF IBADAN LIBRARY Oyeduntan and Durojaiye (Alexander and Allan, 1974). Infectious In view- of the epidemiological significance bursal disease, first described by Cosgrove of the indigenous local chickens, a survey (1962), is an acute contagious viral disease was carried out in some villages to of poultry characterized by the inflammation determine the prevalence rates of ND, IBD of the bursa of Fabricius with its and EDS ’76, which are three very conspicuous enlargement. All breeds of important and vital diseases of poultry in chicken are susceptible, with those between Nigeria. The results are presented in this 2-7 weeks being most susceptible (Ojo et report. al., 1973), although infection has been reported in 20 weeks old birds (Durojaiye et al., 1985). Mortality of between 20-45% Materials and Methods and rapid morbidity reaching 100% in chickens has been reported (Onunkwo, Survey Population 1975), while Louzis et al. (1979) reported mortality of 2-80% in pheasants. The A total population of 2090 local chickens economic losses resulting from IBD include were screened in 5 States namely. Osun, not only the heavy mortalities, but also the Ogun, Lagos, Ekiti and Oyo. These immunosuppression precipitated by the chickens were reared by individuals in small damage to the bursa of Fabricius in flocks, the number ranging from 4-65 and survivors and sub-clinically infected their ages, in most cases could not be chickens which result in increased determined. susceptibility to other diseases (Adene et al., 1985). Preparation o f Sera The EDS ’76 is a viral disease of laying birds firdt described by Van Eck et al. Whole blood was collected from each (1976) and is characterized by sudden drop chicken by jugular venapuncture. The blood in egg production and laying of malformed was allowed to clot under atmospheric eggs. Young birds, though susceptible to conditions and later transferred into a the virus, remain carriers until attainment of refridgerator (4°C) overnight. The scrum sexual maturity w'hen the latent virus is was decanted and clarified by centrifugation activated and infection occurs. The at lOOOr.p.m. for 15 minutes. The clear outbreak of EDS ’76 results in serious serum was stored in Bijou bottle at -20°C economic losses to the farmer and depletion until tested. of protein (eggs and poultry meat) to feed the growing population. Ovvoade and Newcastle Disease Serology Durojaiye (1993) reported the laying of 249 shell-less eggs with a 30% drop in egg Antibodies to ND were detected by the production irt a poultry house of 8,000 haemagglutination inhibition (HI) technique. caged layers. Serial dilutions of each serum sample were 48 UNIVERSITY OF IBADAN LIBRARY Antibodies to three viruses in Nigerian... carried out in WHO microtitre plates using However, in this case, serum dilutions were normal saline as diluent. Each dilution of reacted with 4HA units of the EDS ’76 scrum was reacted with 4HA units of ND vaccine virus. vaccine virus for 30-45 minutes at room temperature. 0.8% of chicken erythrocytes Controls dispensed into every well, including the control wells was used as the indicator. The controls consisted of hyper-immune Reaction was allowed to occur for 30-45 sera prepared in chickens after two minutes after which the results were read. successive vaccinations with known positive The HI titre of a serum was taken as the antigens of ND, IBD and EDS ’76. Birds highest dilution of the serum which inhibited (chickens) known to be free from ND, IBD virus haemagglutination. and EDS ’76 antibodies were used as negative controls. The chickens were kept Infectious Bursal Disease Serology away from other birds and were not vaccinated. . Antibodies to IBD in the sera were determined by the agar gel precipitation Results technique as previously described (Durojaiye et al., 1985). Briefly, 5mm Antibodies to ND and IBD were detected wells were made in 1% Oxoid agar gels in in sera obtained from all sampled areas. 5cm diameter petri dishes. The bursa of The point prevalence from all sampled areas ranged between 91% and 100% for ND and Fabricius from a clinical case of IBD was homogenized in a ten broeck tissue grinder between 17% and 73% for IBD (Table 1). and centrifuged. The supernatant, which Antibodies to EDS ’76 virus were detected served as the bursal tissue antigen, was in all the States sampled but in fewer collected and stored at -4°C until used. The number of samples and the prevalence rates central wells were filled with IBD varied between 3 and 60% (Table 1). A total homogenized bursal tissue antigen, while the of 2010 samples were examined for ND peripheral wells were filled with sera. The antibodies, out of which 1890 (94%) were results were first read at 18-24lh hour and positive. Out of 2090 samples examined for finally read at 72nd hour. The appearance of IBD antibodies, 720 (34%) were positive. specific precipitin lines was taken as the Of 1740 samples examined for EDS ’76 indicator of a positive antibody reaction. antibodies, 500 (29%) were positive.Quantitative antibody assay carried out by EDS 76 Serology HI technique showed that HI titres ranged between 2 and 2048 for ND, and between 2 Antibodies to EDS ’76 virus were detected and 64 for EDS ’76. HI antibody titres were by the use o f the HI technique as described much higher in ND positive sera when for the Newcastle disease serology. compared to the EDS ’76 positive sera (Table 2). 49 UNIVERSITY OF IBADAN LIBRARY Oyedimtan and Durojaiye Table 1 Serological Survey of Antibodies to ND, IBD and EDS ’76 Viruses in Nigerian Local Chickens No. of samples tested/No. of samples positive Percentage positive Sampled --------------------------------------------------------------------------------------- Area ND IBD EDS ’76 ND IBD EDS ’76 Osun 550/540 540/90 310/10 98 17 3 Ogun 330/310 360/190 340/50 94 53 15 Lagos 100/100 150/110 150/90 100 73 60 Ekiti 60/60 60/30 60/20 100 50 33 Oyo 970/880 980/300 880/330 91 31 38 Total 2010/1890 2090/720 1740/500 94 34' 29 Table 2 Range of Antibody Titl es to ND and EDS ’76 Viruses in Nigerian Local Chickens Range of antibody Percentage of positive samples Titres ND EDS ’76 2-4 16.9 42.2 8-16 25.4 46.6 32-64 14.8 11.1 128-256 15.3 Nil 512-1024 10.0 Nil 2048 16.9 Nil 50 UNIVERSITY OF IBADAN LIBRARY Antibodies to three viruses in Nigerian. .. Discussion achieved through intensified veterinary extension services to local chicken owners The results of the serological survey of which though occurring in small groups, indigenous chickens in some Nigerian constitute a high proportion of the total villages suggest a substantial activity of poultry population in Nigeria. When ND, IBD and EDS ’76 in these chickens. aggregated in these small communities, they Adcne et at. (1985) stated that the Nigerian form flocks large enough to merit local chicken were possible carriers of IBD vaccination. Also, the encouragement of virus and could be important in the semi-intensive husbandry for the keeping of epidemiology of IBD in Nigeria. the local chickens is considered helpful in Fulminating ND outbreaks have been the control of these viral diseases in Nigeria. observed in flocks of Nigerian local chicken Further research on the epizootiologic (Hill et at., 1953), suggesting that these complex and on the control of disease in chickens are fully susceptible to ND and rural poultry which would translate to the should be considered as an important factor epizootiologic sanitation in both rural and in the epidemiology of ND. The overall industrial poultries (Adene, 1997) is prevalence rate of 94% obtained in this advocated for. Also, considering the survey is indicative of a very high activity of acknowledged ecological adaptations in ND in these chickens and strongly suggest rural poultry, studies on the varied that they could constitute infected carriers. pathotypes in the population might reveal There is no vaccination programme for peculiar resident strains for exploitation in these roamy chickens at present and since vaccine developments. their movement is unrestricted, they have the potential of continuously disseminating these viruses and infecting commercial exotic References breeds of birds reared in intensively managed farms. It is clear therefore that Adene, D.F., Oyejide, A., Owoade, A.A. successful control of these diseases must Studies on possible role of naturally take cognizance of the role of the indigenous infected Nigerian local chickens and chickens in the circulation of viRises. vaccine virus in the epidemiology of Adequate fencing of commercial poultry infectious bursal disease. Rev. 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