Japan Found First Death from Tick-borne Oz Virus: New in the World

Japan – The Japan's Ministry of Health found the first case of death due to the Oz virus. Although it has not been declared a pandemic or contagious virus, it is the first in the world.

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 on 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.

When she was admitted to the hospital, a hard tick was found sucking blood on the base of her right thigh. She died of myocarditis, an inflammation of the heart, about a month later.

According to the National Institute of Infectious Diseases (NIID), the Oz virus was first detected in 2018 in a hard tick whose academic name is amblyomma testudinarium, in Ehime Prefecture.

Antibodies for the Oz virus have been detected in wild animals such as Japanese macaques, wild boars and deer in Chiba, Gifu, Mie, Wakayama, Yamaguchi, and Oita prefectures. Blood tests of 24 hunters in Yamaguchi Prefecture have also found that two of them tested positive for antibodies of the Oz virus, indicating they may have been infected in the past, according to the ministry.

The Oz virus has so far not been found outside Japan, according to the ministry.

The ticks, featuring hard scales and measuring about 3 to 4 millimeters are different from ticks often found indoors and are most often found in forests and bushes.

Since this is the first confirmed fatal case, it is hard to judge the virus’ severity or danger at this point, said Tadaki Suzuki, an infectious pathology expert at the NIID.

“This case shows that the virus can cause severe symptoms including deaths, but the past detection of people with the antibodies also shows that some people may develop no or only light symptoms,” he said.

The ministry revealed that the best precaution for people is to avoid exposing their skin when in areas where they may come in contact with hard ticks. It advises people going near bushes to wear long-sleeved shirts and pants to avoid getting bitten by them, especially from the spring through the fall when the insects become active. Bug repellants may also help.

Anyone who is bitten by such ticks should visit a doctor instead of trying to remove them themselves, the ministry said.