The 15th case of a highly fatal disease transmitted by ticks has been confirmed in Japan.

Japan's National Institute of Infectious Diseases said a 71-year-old woman in Kumamoto Prefecture tested positive for severe fever with thrombocytopenia syndrome (SFTS) after she checked into a hospital with symptoms of fever and vomiting.

Her family said she walked through grass fields to garden or walk the dog but she has not left the country in the past month.

Of the 15 confirmed patients in Japan, eight have died.

The fatality rate of the tick-borne virus is apparently above ten percent but research is still in its initial stages and statistics may change.