Luvai et al.
Ticks Tick Borne Dis. 2021; 13(1):101860. doi: 10.1016/j.ttbdis.2021.101860.
The first TBE case in Japan has been reported in 1993, and so far, a total of five cases have been confirmed in Hokkaido, the northern island of Japan. TBE serosurveys and detection of TBE virus in ticks revealed that TBE virus also circulates throughout the island of Hokkaido. In addition, TBE may also be present in central Japan, on the island of Honshu in Shimane prefecture.
A seroepidemiological study in wild boars on TBE virus and other tick-borne viruses has been carried out in Nagasaki prefecture in southern Japan. On Tsushima Island in Nagasaki prefecture, TBE positive samples (IgG ELISA and plaque reduction neutralization assay) have been reported in wild boars suggesting that TBE virus (or a very closely related flavivirus) may be present also in this area of Japan.
Tsushima Island is close to the Korea Peninsula, where TBE virus (European subtype) has already been identified. Tsushima Island is as well an endemic area of Japanese encephalitis virus. The TBE virus subtype distributed on Tsushima Island and western Japan remains unclear.