Serological evidence of influenza A/H9 in indigenous birds and level of awareness at live bird markets, Plateau State

Abstract

Avian influenza is a zoonotic disease that can adversely affect humans and animals. Nigeria first reported an outbreak of avian influenza which was caused by subtype H5N1 in 2006, thereafter virological and serological surveys revealed the importance of local birds in live bird markets and the community at large in the epidemiology of avian influenza in the country. In the present study, 276 serum samples were collected for serological testing over five months from apparently healthy local birds in live bird markets within two Local Government Areas of Plateau State, to determine antibody prevalence to avian influenza A virus. The detection of influenza A antibody was carried out using an Enzyme-linked immunosorbent assay and further tested by haemagglutination inhibition to determine the specific serotype of the influenza A virus. The result showed a prevalence of 30.4% (n=84) of antibody to influenza A, 26% (n=72) of serotype H9, 1.4% (n=4) of serotype H7, and none was confirmed to be H5 serotype. Comparatively, Jos-North had a lower relative risk with a prevalence of 18.9% (n=18) to the disease as compared to Jos-South with a prevalence of 36.5% (n=66). This study showed the presence of low pathogenic avian influenza A virus in live bird markets within the study area with the dominance of antibodies to H9. To our knowledge, this is the first serological indication of serotype H9 in Plateau State and Nigeria. Evidence of influenza A/H9 in an ecological niche known for the circulation of subtypes H5Nx may complicate the epidemiology and control of avian influenza in the region and Nigeria at large. The level of awareness by the live bird market operators about avian influenza (AI) was relatively low as indicated by the questionnaire survey conducted. Live bird market operators and poultry farmers need to maintain a high level of biosecurity and limit mixing local birds with commercial poultry to prevent the transmission of the virus which may have adverse effects on poultry production, national and international trade, the economy and public health.