ABSTRACT
Since between 1989 and 1991, broiler, broiler breeder and layer chickens reared in three different prefectures of Japan, Hyogo, Ibaraki, and Miyazaki, were diagnosed clinically as having swollen head syndrome (SHS) these flocks were survey for antibody to turkey rhinotracheitis (TRT) virus using a serum neutralisation (SN) test. TRT-specific SN antibody was found in flocks of chickens in 2 out of the 3 prefectures. Thereafter, particular in the summers of both 1993 and 1994 outbreaks of SHS occurred in almost all areas of major chicken production in Japan. Almost chicken flocks affected by SHS possessed TRT SN antibody. No chicken sera collected between 1972 and 1988 possessed any SN antibody to TRT virus. It is suggested that in Japan, TRT virus is widely prevalent in areas of major poultry production.
