Background: Flock surveillance systems for avian influenza (AI) virus play a critical role in countries where vaccination is not practiced so as to establish the epidemiological characteristics of AI needed for the development of prevention and control strategies in such countries.
Materials And Methods: As part of routine AI monitoring in southwest Nigeria, a competitive ELISA was used for detecting influenza A virus antibodies in the sera of 461 commercial breeder and layer birds obtained from different flocks in Oyo State, Nigeria while haemagglutination inhibiting antibodies against low pathogenic AI viruses (LPAIVs) were detected using H5N2, H7N7 and H9N2 subtype-specific antigens. Suspensions prepared from cloacal swabs were tested for AI virus RNA using reverse transcriptase-polymerase chain reaction.