Apoptosis in field and experimental cases of avian influenza H9N2 infection in broiler chickens in Iran.

Avian influenza virus subtype H9N2 is widely circulating around the globe affecting many species of animal including mammals and birds as well as human beings. The virus has pandemic potential due to segmented nature of the viral genome. Ultra-structural features of apoptosis in field and experimental infection of H9N2 avian influenza virus were studied. Freshly dead birds from affected broiler farms and experimentally infected broiler chickens with H9N2 subtypes were subjected to routine necropsy. Post-mortem findings in different organs were recorded. Appropriate specimens from the trachea were taken for electron microscopy studies. In electron microscopy study, frequent apoptotic bodies were observed in the epithelial cells of the trachea. Increase of antibody titer to H9N2 virus following challenge with the virus in experimental group indicates that the infectious cycle has been initiated in the affected birds.