Determinants and Sero-Prevalence of Avian Influenza (H5 & H7 Sub Types) in Industrial and Backyard Poultry of Iran -2014

Influenza is an acute, highly contagious disease of a variety of both domestic and wild bird species. The aim of this study was to estimate subclinical infections or previous exposure to H5 and H7 subtypes and to discover potentially important determinants of the prevalence of this disease in industrial and backyard poultry in Iran.
A survey was conducted from September to December 2014 in Iran using a cross-sectional design throughout the entire country. The Enzyme-Linked Immunosorbent Assay (ELISA) was used as the screening test and all ELISA-positive samples were examined with the HI test to differentiate H5 and H7. A total of 1378 places and 31547 birds were sampled.
One place (bird garden) out of 1378 was positive for the H7 subtype and six places (2 bird gardens, 3 villages, and 1 ostrich farm) out of 1378 were positive for the H5 subtype on HI test. The results of this study showed that the presence of a lake (OR=12.20, CI 95% 2.19-68.09) and live bird marketing (11.73, CI 95% 1.32-104.42) were risk factors for the H5 subtype.
Sampling migratory waterfowl birds is recommended for early detection of probable infections and preventing the spread of infection to the backyard and industrial poultry because of their role in the transmission of the disease and probability of circulation of the virus.