A woman in her 70s in Ibaraki Prefecture who had suffered a tick bite died of myocarditis last year after being infected with the Oz virus, the health ministry said Friday.

While there have been reports of possible infections with the tick-borne virus in wildlife and humans, this is believed to be the world’s first fatal case, the ministry said.

According to the ministry, the woman, who did not have a history of traveling abroad, visited a medical institution last summer with symptoms including fever, fatigue and joint pain. She was suspected of having pneumonia and prescribed antibiotics, but her symptoms worsened and she was hospitalized at Tsukuba Medical Center.