Japan Reports Record Cases of Deadly Tick-Borne Illness

The Japan Institute for Health Security, located in Tokyo's Shinjuku Ward, has released concerning preliminary data regarding a tick-borne illness. Health officials are urging caution as Japan has recorded a record number of infections from this potentially fatal disease this year.

The data, released on August 19, 2025, indicates a total of 135 cases of severe fever with thrombocytopenia syndrome (SFTS). This surpasses the previous high of 134 cases reported in 2023. This marks the highest number of cases since the infectious disease was first identified in Japan in 2013.

SFTS is transmitted through the bites of infected ticks, which are commonly found in grassy areas. Typical symptoms of the illness include fever, vomiting, and abdominal pain. The health ministry reports that the disease has a case fatality rate ranging from 10 to 30 percent, with elderly patients being at a higher risk.

The disease also affects pets, often with a higher fatality rate, which poses a transmission risk to their owners. Human cases have been steadily increasing, with over 100 reported annually since 2021. While infections have historically been concentrated in western Japan, cases this year have also been reported in the Kanto region, including Tokyo, and as far north as Hokkaido.

Health officials are advising the public to take preventative measures, especially during the warmer months from spring through fall, when tick activity is at its peak. Recommendations include wearing long-sleeve shirts and long pants when walking through grassy or forested areas to minimize skin exposure to ticks.