Serological Survey of Avian Influenza (H9N2) Among Different Occupational Groups in Tehran and Qazvin Provinces in IR Iran

Background: In the last decade H9N2 avian influenza viruses had caused outbreaks in poultry in many parts of the world. This subtype could infect other animals such as human and pig. Avian H9N2 virus has acquired receptor binding characteristics typical of human's strains, increasing the potential for reassortment in both human and pig respiratory tracts. This indicates that the A/H9N2 would be a potential threat to human population. Objectives: The aim of this was to indentify the presence of A/H9N2 virus among different high risk occupational groups, in Tehran and Qazvin provinces in seasonal outbreak in Iran. Material and Methods: 182 sera were collected from the poultry farms and slaughterhouse workers, and animal vaccinators and also veterinarians in seasonal outbreak (December 2010, January 2011 and July 2011). Hemagglutination Inhibition (HI) and ELISA assays were performed to detect anti-H9 antibody. Sera adsorption was performed to eliminate cross-reactivity between anti-H3 and anti-H9. In HI test the titer >= 20 was considered to be positive. Results: Only 3 (1.64%) in HI that showed titer >= 20 and 21 (11.53%) sera in ELISA showed OD > 0.7 were assumed positive for H9 virus infection. Conclusions: The findings of this study show that H9N2 avian influenza virus can infect human. Repeated interspecies transmission H9N2 viruses from poultry to human raises concerns about adapting of this subtype with new host.