Between December 23, 1995 and Japnuary 7, 1996, a rapidly spreading outbreak of a bovine respiratory infections occured at 3 dairy farms in Hyogo prefecture, Japan. Clinical symptoms of the infected animals were almost same among 3 farms. Clinical sings of the infected animals recovered 8-10 days after antibiotic treatments. A significant increase of the neutral antibody titers to RS virus were observed and Pasteurella haemolytica was isolated from some animals. Therefore, this outbreak was suspected to be compound infections of RS virus and Pasteurella haemolytica. All 3 farms introduced pregnant heifers from an area in Hokkaido on December 10, 1995 and some of these animals had high antibody titers to RS virus. Therefore, this outbreak might be caused by the introduction of some virus-infected animals from an area in Hokkaido.
