The Japanese health ministry says a woman that died last year may be the first person to contract a deadly tick-borne disease from another mammal.

The woman, who was in her 50s, was bitten by a stray cat. She was taken to a veterinary hospital, but died 10 days later, showing signs of a severe fever with thrombocytopenia syndrome (SFTS), which has a fatality rate of up to 30 percent. Symptoms include fever, vomiting, and diarrhoea

Although this disease is transmitted by ticks, the woman showed no sign of being bitten by a tick. Thus, the Japanese health ministry has now concluded that it was the cat who was infected first, making this the first mammal-to-human transmission of such a disease.

“No reports on animal-to-human transmission cases have been made so far," a Japanese health ministry official told the AFP news agency. "It's still not confirmed the virus came from the cat, but it's possible that it is the first case.”

Across Japan, China, and South Korea, SFTS is quite a new infectious disease. It first emerged in 2013 in Japan and since then 57 of the 266 people infected with the disease have died. Currently, there is no effective treatment for SFTS.

About 60 people contract the disease every year in Japan, but there are no preventative medicines or vaccines yet available.

“There are only symptomatic therapies, such as dealing with fever or diarrhoea,” the ministry official said, reported French news site France 24. “The best way to avoid the infection is not to be bitten by ticks.”

A recent paper in Nature noted that tick bites are commonly painless, so some patients don’t even know they’ve been bitten. It also noted that the relationship between SFTS infection and various tick species needed to be further investigated.

“Early diagnosis is very important for treatments of SFTS cases,” that paper notes. “Longer interval from illness onset to confirmation can lead to a delay in the key period for treatment.”

While this particular case seems to have been extremely rare, the Japanese health ministry is now urging people to be cautious when coming into contact with stray animals.