Characteristics of a hepatozoonosis in lungs of Japanese black bears (Ursus thibetanus japonicus)

In a survey of pathologic agents in the wild animals of central Japan, we found a Hepatozoon sp. in the lungs of Japanese black bears in Fukui, Shiga, and Gifu Prefectures, Japan. Histopathologic examination of organs and tissues from the 18 bears inspected showed hepatozoonosis in all. Immature and mature meronts were found in all lobules and between alveoli, with a few found between pleura and in connective tissue. In the lungs, inflammatory cells were not found around meronts, merozoites, or tubercles made of macrophages including zoites, but inflammatory cells were found around degenerating cells, zoites, and tubercles. A Hepatozoon sp. has not been reported as being detected in bears of any species before.