摘要
Influenza type A, is an avian disease with a complicated ecology and transmission routes in verity of avian and mammalian species. The present study aimed to demonstrate the characteristic, clinical and experimental features as well as pathogenecity of Avian Influenza Virus H5N2 through a laboratory-based experiment in western Iran. A post-mortem examination of experimentally chickens was undertaken in 2007. Overall 25 local native chickens including 15 layers and 10 roosters suspected with AI infection as well as 50 experimental chickens were studied. The virus was isolated from the embryonated specific pathogen-free （SPF） chicken eggs. There was an embryo mortality rate of 71% within 48 hours post inoculation （PI）. Hemagglutinin （HA） inhibition titres against AIV subtype H5N2 in the layers ranged from 4.20 to 4.75 （acute） and 6.21 to 7.82 （convalescent）. Accumulated mucous in trachea of the dissected birds, congested lungs, atrophied bursa, haemorrhagic cecal tonsils and inflamed thymus were the main clinical symptoms. Thickened and infected air sacs, pre hepatitis and enteritis signs were also observed, in experimental birds, the eyes＇ colour became red and the eyelashes were almost double in diameters after being infected. The AI virus found in the present study was classified as a highly pathogenic avian influenza.
