Avian Influenza (H9N2) among poultry workers in Iran

Background and objectives: A number of different subtypes of avian influenza (AI) viruses have emerged in humans including H5N1, H7N2, H7N7 and H9N2. These influenza viruses are excreted in the infected birds and in their respiratory secretions. The aim of this study was to investigate seropositivity against H9N2 and H7N7 viruses among poultry and slaughterhouse workers with occupational risk of exposure to poultry in Tehran province. Materials and Methods: A cross-sectional seroprevalence study was performed using two types of HI assay among 127 poultry and slaughter-house workers and 25 controls with the regular consumer related exposure to poultry against H9N2 and H7N7 avian influenza viruses. Data were analyzed using SAS 9.1. Results: There was no evidence of previous H7N7 infection among subjects. Both poultry workers had elevated antibodies against H9N2 Influenza viruses compared to controls. Slaughter-house workers who self-reported eviscerating poultry with their bare hands had markedly increased evidence of previous H9N2 infection (15.7%) compared to controls (0%) (OR=18.241, 95% CI ([6.802-48.914]). Conclusions: Our results suggest poultry-to-human transmission of avian influenza A H9N2 can occur in poultry workers. Eviscerating section workers, in contrast to others had the highest risk of H9N2 infection. It is emphasized that eviscerating sections of poultry work is the most contaminated part of poultry industry that could increase the likelihood of poultry-tohuman transmission.