Fatal SFTS Virus Sparks Concern in Japan After Suspected Animal-to-Human Transmission Death

Mie Prefecture, Japan – The Japan Veterinary Medical Association (JVMA) has issued a call for heightened precautions among veterinarians following the death of a veterinarian in Mie Prefecture, suspected to be the first case of animal-to-human transmission of the severe fever with thrombocytopenia syndrome (SFTS) virus in Japan. The incident occurred in May 2025, when the veterinarian, whose identity has not been disclosed, developed symptoms after treating an infected cat at his clinic.

According to a JVMA official, the veterinarian was hospitalized but succumbed to the illness shortly after. SFTS is a tick-borne viral disease with no known cure, characterized by symptoms such as high fever, vomiting, and low platelet counts, which can lead to severe complications. The mortality rate for SFTS can range from 15% to 30%, based on data from the World Health Organization (WHO).

Notably, an autopsy failed to identify a tick bite on the veterinarian, which is the typical mode of SFTS transmission. This has raised questions about the exact mechanism of infection in this case. Neither the cat’s owner nor other staff at the clinic have reported symptoms, adding to the uncertainty surrounding the transmission.

SFTS was first identified in China in 2009 and has since been reported in Japan, South Korea, and other parts of East Asia. In Japan, cases have primarily been linked to tick bites in rural areas, with the Ministry of Health, Labour and Welfare reporting approximately 40–100 cases annually, mostly in western Japan. This incident marks a potential shift, as it suggests the possibility of direct animal-to-human transmission, a rare occurrence according to existing research.

The JVMA has advised veterinarians to use protective equipment, such as gloves and masks, when handling animals suspected of carrying the virus. The association is also collaborating with health authorities to investigate the case further and prevent future occurrences.

Health officials are urging the public, particularly those in rural areas, to take precautions against tick bites, such as wearing long clothing and using insect repellent, as ticks remain the primary vector for SFTS transmission. Research into vaccines and treatments for SFTS is ongoing, but no specific antiviral therapy is currently available.