Abstract
In March of 1986, a cow on a dairy farm in Fukuoka Prefecture became ill displaying mainly nervous symptoms. She was treated with antibiotics but later slaughtered because of a poor prognosis. The results obtained by the hematological and biochemical examinations suggested a bacterial infection. An autopsy revealed the formation of a pigeon-egg sized abscess in the bottom of the brain. Histologically, necrosis, intense infiltration of neutrophils and bacterial clumps were observed around the hypophysis. Actinomyces pyogenes (A. pyogenes) was isolated from the lesion. A serological survey on A. pyogenes infection was performed with other cows on the same farm. As a result, A. pyogenes protease antibody was detected in 17 out of 19 cows.
