Abstract
From July 2012 to December 2012 (for six months), hepatic grayish white solid nodules were observed in 53 of 610 horses brought to a slaughterhouse in Fukuoka Prefecture. We performed both histopathological and genetic examinations on these materials to investigate larval Echinococcus multilocularis infections. Based on the results of these examinations, 39 horses were diagnosed with alveolar hydatid disease (the infection rate was 6.4%). Infections of larval E. multilocularis were observed not only in light breed horses, as has been reported previously, but also in various other types of horses, including ponies, Japanese draft horses and Hokkaido ponies. In the epidemiological survey, we were able to confirm that 4 horses had been raised in Hokkaido, where alveolar hydatid disease is endemic, and they might have been infected by larval E. multilocularis there. On the other hand, we could not confirm that most of the horses infected by larval E. multilocularis in the present survey had been raised in Hokkaido, and we had difficulty in detecting where they had been infected by larval E. multilocularis. But, considering the regional distribution of E. multilocularis in Japan and the statistical analysis data of horses born in Japan, we could not completely deny the possibility that they also might have been infected by larval E. multilocularis in Hokkaido.
