Molecular detection of apicomplexan protozoa in Hokkaido brown bears (Ursus arctos yesoensis) and Japanese black bears (Ursus thibetanus japonicus)

Many tick-borne pathogens (TBPs) are present in wildlife. The objective of this study is to reveal the role of wild bears in maintaining TBPs. A total of 49 brown bears (Ursus arctos yesoensis) from Hokkaido, and 18 Japanese black bears (Ursus thibetanus japonicus) from Tochigi, and 66 Japanese black bears from Nagano were examined by two molecular methods, reverse line blot (RLB) hybridization, and nested PCR. A total of 5 TBPs (Hepatozoon ursi,Babesiasp. UR2-like group,Cytauxzoonsp. UR1,Babesiasp. UR1, andBabesia microti) were detected from bear blood DNA samples.B. microtiwas detected from blood DNA samples of Japanese black bear for the first time, with the prevalence of 6.0% (5/84). Out of detected pathogens,H. ursi,Babesiasp. UR2-like pathogens, andCytauxzoonsp. UR1 were considered as three of the most prevalent TBPs in bears. The prevalence ofH. ursiwere significantly higher in Japanese black bear (0% vs 96.4%) while that ofBabesiasp. UR2-like group was higher in Hokkaido brown bears (89.8% vs 40.5%). The prevalence ofBabesiasp. UR1 were significantly higher in Japanese black bears from Tochigi (44.4%), comparing with those from Nagano (18.2%). The prevalence of the detected TBPs were significantly higher in adult bears, comparing with those in younger bears. The present study suggests that Japanese bear species contribute in the transmission of several TBPs in Japan. The expanding distribution of bears might cause the accidental transmission of TBPs to humans and domestic animals.