Serosurvey of antibody to highly pathogenic avian influenza (H5N1) in pigs, north central Nigeria

Avian influenza is a disease of economic and public health importance that has been described in most domestic animals and human. Highly pathogenic avian influenza H5N1 epidemic in Nigeria was observed in agro-ecological zones where pigs and chickens are raised in shared environment with chances of interspecies transmission. We investigate the likelihood of transmission of the disease to pigs in North Central Nigeria where there were several cases of highly pathogenic avian influenza H5N1 in both commercial and free range poultry. Two hundred and twenty swine sera collected in Kaduna and Plateau states were screened for influenza A/H5N1 antibody by haemagglutination inhibition test according to standard protocol. All the sera tested were negative for influenza A/H5 antibody (HA titre < 22). Our inability to detect appreciable antibody level to avian influenza A/H5N1 therefore may be due to lack of infection because of low susceptibility of pigs to Influenza A/H5N1. We recommend wider serological and virological studies to identify other circulating influenza virus in pigs in different agro-ecological zones to provide useful epidemiological data on evolving influenza virus.