The presence of Theileria sergenti in Haemaphysalis longicornis overwintering in pasture in Japan.

Unfed Haemaphysalis longicornis ticks were collected from the soil of pasture during the winter and their salivary glands were examined by the methyl green pyronin staining method in order to detect overwintering of Theileria sergenti, the causative agent of bovine theileriosis in Japan. A transmission experiment was carried out using these ticks applied to a splenectomized calf. The protozoa which appeared in the peripheral blood were identified parasitologically and seroimmunologically as T. sergenti. The results suggested that T. sergenti in Japan might overwinter in H. longicornis which moulted after repletion on infected cattle in the autumn and hid in the soil during the winter. Moreover, it seemed possible that T. sergenti might develop to the infective stage in H. longicornis during the overwintering period.