Abstract
Three collective outbreaks of bovine actinobacillosis were observed in Japan during the past ten years. The results of observation are summarized as follows. (1) In Tottori Prefecture, 50 affected cows were reported during a period from 1962 to 1965. Then 35 cows in Hokkaido and 123 in Miyazaki Prefecture were affected during a period from 1975 to 1976. Morbidity was 8.8, 7.1 and 13.8 per cent, respectively. The majority of the affected animals were females of the Japanese Black breed 2 to 10 years old. The disease occurred most frequently in autumn to winter. (2) In the affected cows, marked swelling and abscess developed in the submaxillary, pharyngo-laryngeal, buccal and/or prescupular areas. Discharge of pus from the lesion was observed in some cows. Most of the affected cows recovered after antibiotic or surgical treatment. (3) Six strains of Actinobacillus lignieresii were isolated in pure culture from 6 out of 14 nodular lesions examined. They belonged to serotype 4 or 5. (4) The affected cows had a significantly higher agglutinin titer in serum than healthy ones (P<0.001). (5) Histologically, all the nodular lesions contained characteristic eosinophilic sulfur granules.
