A SEROLOGICAL SURVEY OF TURKEY RHINOTRACHEITIS VIRUS-INFECTION IN CHICKENS IN JAPAN

A total of 4,111 chicken sera collected from 1985 to 1995 at 137 farms in 36 prefectures were subjected to an enzyme-linked immunosorbent as say (ELISA) to test for antibodies against turkey rhinotracheitis (TRT ) virus. The antibodies to TRT virus were detected in the chicken sera collected from 1988 to 1995, but the antibodies to TRT virus were und etectable in the sera of chickens collected before 1987. The antibody positive rates each year ranged from 2.2% (1988) to 54.2% (1995). Rece ntly, the TRT virus has spread over the flocks of commercial broiler a nd layer chicken throughout the country. The serological findings indi cated that the TRT virus had invaded the chickens before 1988, and has been widespread thereafter in Japan.