Japan sees world’s first death from tick-borne Oz virus

Tick-borne Oz virus

A woman in her 70s died in Ibaraki prefecture, northeast of Tokyo, after contracting the Oz virus, making her case the world’s first death by the possibly tick-borne infection, Japanese authorities said on Friday.

The virus was discovered in the country in 2018, and while there may have been cases of humans and wild animals being infected, there had been no confirmation of its onset on a person until now, the authorities said.

The woman went to a medical institution in the summer of 2022 after developing symptoms, including fever and fatigue, according to the prefectural government and the health ministry.

She was diagnosed with pneumonia, but after her condition worsened, she was hospitalised, and an engorged tick was found on her upper right thigh, they said.

She died of myocarditis, an inflammation of the heart muscle, 26 days after she was hospitalised.

No vaccine exists against the Oz virus, which has not been found outside Japan, according to the National Institute of Infectious Diseases in Tokyo.

The institute has said that being infected by the virus is not necessarily fatal, but more studies need to be conducted on its symptoms and dangers.

The virus was first detected in 2018 in the Amblyomma testudinarium tick found in the western prefecture of Ehime.

The Oz virus is thought to be transmitted through the bite of the tick, the institute said, with the species existing across a wide area of Japan.

Antibodies have been found in wild monkeys, boars and deer in Chiba prefecture, near Tokyo, the central prefectures of Gifu and Mie, the western prefectures of Wakayama and Yamaguchi and the southwestern prefecture of Oita.

Two hunters in Yamaguchi also reportedly tested positive for the antibodies, the institute said.

“It is important to cover as much skin as possible when entering grassy areas so that you won’t get bitten by these ticks,” said an official at the Ministry of Health, Labour and Welfare.