The Japanese government is advising travelers to be aware of Severe Fever with Thrombocytopenia Syndrome (SFTS), a tick-borne infectious disease, as cases reach a record high.

In 2025, reported cases reached 191 nationwide, a record high for Japan. As cases in western Japan continue to grow, the outbreak has also spread to the Kanto region, with the first cases being reported in Kanagawa Prefecture.

Cathay General Hospital Dermatologist Lo Yang (羅陽) says severe tick-borne diseases can cause neurological and systemic symptoms and have a high mortality rate. He advises travelers to wear long sleeves and long pants when outdoors to avoid bites, and to seek medical attention immediately if bitten.

Lo points out that most tick-borne diseases are caused by hard ticks, which are commonly found on small mammals such as mice in grassy areas, but can also be found on larger mammals such as deer. While less serious cases include local inflammation and swelling, Lo says there is a risk for contracting Lyme disease, which can affect the joints, heart, and nervous system.

The Centers for Disease Control (CDC) announced Taiwan’s first SFTS case in 2019. According to the CDC, the incubation period is around 7 to 14 days, and the first symptoms include redness, swelling, rashes, blisters, or bruising at the bite site, as well as fever, nausea, and loss of appetite.

Lo extends the Japanese government’s advisory to those visiting grasslands in Taiwan, recommending long sleeves and long pants. He suggests tucking pants into socks and checking for tick bites after visits to outdoor areas. If found, seek medical attention promptly.