Abstract

A total of 672 sera from apparently healthy commercial and indigenous chickens of different ages were screened for antibodies to infectious bronchitis (IB) virus using the enzyme-linked immunosorbent assay (ELISA). Samples obtained from breeder, layer, grower and indigenous chicken flocks in Oyo, Ogun, Ondo and Lagos states of southwestern Nigeria were screened. The total seroprevalence was 82.7% with ELISA units of 77.0 ± 8.0. Among the groups of birds, layers had the highest ELISA units of 80.0 ± 9.0, breeders had 73.0 ± 8.0 while indigenous chickens had 73.0 ± 7.0 ELISA units. These chickens, except the breeders, had no history of vaccination against infectious bronchitis. The higher prevalence observed in layers, growers and indigenous chickens may be due to field infection since maternal antibody wasexpected to have waned between three and four weeks of life. These findings indicate a high infectious bronchitis virus activity in southwestern Nigeria chickens hence there is an urgent need for the development of prevention and control policies against IB in Nigerian poultry farms and a national control programme for infectious bronchitis virus infection should be planned.

Key words: Chickens, infectious bronchitis virus, Nigeria, prevalence, southwest.