Tick-borne "SFTS" Reaches Record High: 135 Infected Nationwide — Mortality Rate About 30%, First Occurrence in Hokkaido, Japan

The number of domestic infections of Severe Fever with Thrombocytopenia Syndrome (SFTS), transmitted by ticks, reached a cumulative total of 135 by August 10, 2025, surpassing the previous record of 134 in 2023, making it the highest ever recorded. The fatality rate is approximately 27-30%, with a high risk of severe cases particularly among the elderly. This year, the geographical spread has expanded, with the first case confirmed in Hokkaido. According to a report from the National Institute of Health Crisis Management (JIHS) and various media outlets, infections are predominantly reported in western Japan, including Kochi, Nagasaki, Oita, Shimane, and Kumamoto, but cases have also been reported in northern Japan. Infections transmitted through pets (cats and dogs) and human-to-human transmission among healthcare workers have been reported domestically, necessitating caution. In terms of treatment, the antiviral drug Favipiravir (Avigan) was approved and covered by insurance for SFTS in 2024, raising hopes for preventing severe cases. This article provides a detailed explanation of the latest trends, symptoms and diagnosis, treatment, preventive measures, pet precautions, and practical advice for foreign residents, including travelers, based on primary information and government materials. As the latest information may change with weekly report updates, continuous verification of official data is recommended.