Photo/Illutration Stray cats that are unrelated to the domestic cat in Ibaraki Prefecture that tested postive for the severe fever with thrombocytopenia syndrome (SFTS) virus in May (Asahi Shimbun file photo)

A domestic cat in Ibaraki Prefecture has been confirmed to have contracted a potentially deadly tick-transmitted disease, believed to be the first reported case in the Kanto region. 

The cat, which later died, tested positive for the severe fever with thrombocytopenia syndrome (SFTS) virus in May. 

The same month, a veterinarian treating a hospitalized cat in Mie Prefecture died from SFTS, prompting a warning to be issued across the nation. 

Experts are warning as areas at risk of the infectious disease are spreading.

Ken Maeda, head of the veterinary science department of the Japan Institute for Health Security, said that he could not comment on individual infection cases but added, “The risk is rising even in the Kanto region, too. We need to be prepared with a sense of urgency.”

Symptoms of SFTS include fever, vomiting and diarrhea. The fatality rate in humans is 30 percent and in cats it is as high as 60 percent.

Infections have been reported mainly in western Japan.

The first infection confirmed in the Kanto region was a 1-year-old female cat, according to Ibaraki prefectural and other officials.

The cat had been kept indoors, but in late April, after temporarily escaping outdoors, many small ticks were found embedded in her ears.

The cat was taken to a nearby veterinary hospital.

On May 9, after the ticks were removed, the cat was seen again with a high fever of 40.9 degrees, loss of appetite and vomiting. The following day, the cat also developed jaundice.

The veterinarian, suspecting SFTS from the symptoms, contacted the prefectural government on May 12.

Prefectural workers then tested the cat's blood components, which were confirmed to be infected with the SFTS virus.

The cat was nursed at the owner’s home in an isolation cage, but died on May 12.

According to the prefectural government, a notice was issued in late May to veterinarians through the prefectural veterinary medical association, calling for infection control measures to be taken.

In the prefecture, six cats and two dogs have been tested so far for the suspected virus, including this case.

This was the first positive test for the virus, according to the prefecture.

No transmission from the cat to the owner, veterinarian or other humans has been confirmed in the prefecture, officials said.

According to the Japan Institute for Health Security, the number of SFTS infection cases has been on the rise since the virus was first confirmed in Japan in 2013.

More than 100 cases were reported annually from 2021 to 2024, and a record 134 infections were logged in 2023.

In addition to humans, cats and dogs have been mostly infected in western Japan.

However, the infections spread to the Chubu region, with cases in Aichi and Shizuoka prefectures in 2021 and Toyama Prefecture in 2022.

In the Kanto region and northern Japan, there had been no officially confirmed cases in humans, cats or dogs except for a case in which a man in his 70s in Chiba Prefecture was infected in 2017 and this was discovered four years later. 

The Tokyo Veterinary Medical Association prepared a manual for veterinarians in 2021 and a video on preventing SFTS infections in 2022.

Kiyoshi Nakagawa, vice chair of the association, said, “We have been thinking that a case could be confirmed at any time in Tokyo or the Kanto region.”

Maeda of the Japan Institute for Health Security said to prevent infections, “If it is a cat, keep it indoors, never directly touch its bodily fluids when it is sick and disinfect the cage. If you take measures such as wearing gloves and masks, you can reduce the risk considerably.”

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