Abstract: In order to study the infection situation of avian leukemia virus(ALV) in different import breeds in China, more than 7000 cloacal swabs and serum samples from 4 different province were collected, then ALV-A/B, ALV-J antibody and p27 antigen were detected by ELISA. Samples collected from 4 different located poultry farms, which include 115 groups of 5 different breeds. Our investigation indicated ALV-J and ALV-A/B infection are existed in the import breeds of China generally. Moreover, the positive antibody rate of ALV-J was much higher compared to the ALV-A/B and the antibody rate of ALV-J was higher in broiler than in layer. Our investigation also showed chicken in early stage of egg production had top positive rate of p27 antigen and ALV-J antibody.

Key words: avian leukemia; epidemiological study