An outbreak of infectious bursal disease in eight weeks old IBD vaccinated commercial poultry flock in Maiduguri, Nigeria

Abstract

An outbreak of infectious bursal disease (IBD) on an IBD vaccinated commercial poultry farm was investigated using clinical and pathological findings as well as antigen and antibody detection by agar gel immunodiffusion test (AGDT). Mortality was observed 3 days after the onset of clinical signs and peaked on day 5 but declined significantly on day 6 after the onset of the clinical signs. The clinical and pathological lesions observed were those of hurdling anorexia, diarrhoea, hemorrhages on the thigh and breast muscles and on the gizzard-proventriculus junction as well as inflamed bursa. A morbidity rate of 90%, mortality rate of 53.3% and a case fatality rate of 59.3% were recorded. The sera collected on day 3 post infection were negative for IBD virus precipitin antibodies, while the sera obtained 15 days post-infection had IBD virus precipitin antibodies with titres ranging from 1:16 to 1:128. In addition, the tissue from infected bursae were all positive for IBD virus precipitin antigens with titres ranging from 1:2 to 1:32. The outbreak could have arisen from IBD vaccination failure. Keywords : infectious bursal disease outbreak, vaccination failure, agar gel immuno-diffusion test, Nigeria Tropical Veterinarian Vol. 22(3&4) 2004: 93-98