Outbreaks of infectious bursal disease in vaccinated chicken flocks are frequent in Nigeria. For the control of infectious bursal disease, live vaccines based on foreign infectious bursal disease virus (IBDV) strains are used. The present study investigated the phylogenetic relationship between field and vaccine IBDV strains from northwestern Nigeria. Thirty field IBDV strains and three commercial vaccines strains were characterized through sequencing the VP2 hypervariable region. In addition, the complete genome segment A coding region for two vaccines and two field strains was sequenced. The deduced amino acid sequences (position 212 to 331) of IBDV strains from Nigeria and other regions of the world were aligned and possible regional and virulence markers were identified associated with VP2 minor hydrophilic peaks. Reversion to virulence of a vaccine strain with a Q to L mutation at position 253 was observed. Phylogenetic analyses revealed a unique cluster of northwest Nigerian field IBDV strains alone or related to imported characterized classical and very virulent IBDV vaccines. The results suggest that when IBDV strains spread from their region of origin to a different region they mutate alongside indigenous field strains but may retain their identity on the VP2 region.

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Field outbreaks of coccidiosis all over the world were commonly reported in chickens over 3-weeks of age. Outbreak of coccidiosis in birds in the first few weeks of life is becoming increasing important but chickens less than 1-week of age appeared not to be susceptible. This case report describes the clinical signs and gross lesions of coccidiosis as well as its microscopic appearance in a five-day old intensively managed broiler breeder chicks. The outbreak occurred in December, 2009 and was characterized by early onset of an acute disease with high mortality. Other clinical features of the disease were: progressive increase and sudden decline of high chick mortality of up to 50%, ruffled feathers, blood stained whitish to brownish diarrhea, weakness and anorexia. Gross lesions seen were congested carcasses, distended caeca and intestinal segments with blood, mucus and tissue debris; retained yolk sac was also observed in some birds. Whole intestines were submitted to the Protozoology and retained yolk sac to Microbiology Laboratories for investigations. A farm visit revealed very poor housing ventilation and wet litter. Laboratory results confirmed coccidian schizonts and gametocytes from caeca and intestinal scrapings. Escherichia coli was isolated from the yolk sac. High hygienic standards must be maintained in hatcheries and poultry houses, damp and warm litter must be avoided and adequate ventilation should always be provided in poultry houses to prevent coccidiosis.

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