Emerging infectious disease caused by a new nairovirus identified in
Japan

Date:
October 4, 2021
Source:
Hokkaido University
Summary:
A previously unknown virus that can infect humans and cause disease
has been identified by scientists in Japan. The novel infectious
virus, named Yezo virus and transmitted by tick bites, causes a
disease characterized by fever and a reduction in blood platelets
and leucocytes.



FULL STORY ==========================================================================
A previously unknown virus that can infect humans and cause disease has
been identified by scientists in Japan. The novel infectious virus, named
Yezo virus and transmitted by tick bites, causes a disease characterized
by fever and a reduction in blood platelets and leucocytes. The discovery
was made by researchers at Hokkaido University and colleagues, and the
results have been published in the journal Nature Communications.


========================================================================== Keita Matsuno, a virologist at Hokkaido University's International
Institute for Zoonosis Control, said: "At least seven people have been
infected with this new virus in Japan since 2014, but, so far, no deaths
have been confirmed." The Yezo virus was discovered after a 41-year-old
man was admitted to the hospital in 2019 with fever and leg pain after
being bitten by an arthropod believed to be a tick while he was walking
in a local forest in Hokkaido. He was treated and discharged after two
weeks, but tests showed he had not been infected with any known viruses
carried by ticks in the region. A second patient showed up with similar symptoms after a tick bite the following year.

Genetic analysis of viruses isolated from blood samples of the two
patients found a new type of orthonairovirus, a class of nairovirus,
that includes pathogens such as the Crimean-Congo haemorrhagic fever
virus. The scientists named it Yezo virus, after a historical Japanese
name for Hokkaido, a large island in the north of the country where the
virus was discovered. The novel virus was found most closely related
to Sulina virus and Tamdy virus, detected in Romania and Uzbekistan, respectively, the latter of which reportedly caused acute fever in humans recently in China.

The scientists then checked blood samples collected from hospital
patients who showed similar symptoms after tick bites since 2014. They
found additional positive samples from five patients. These patients,
including the first two, had a fever and reduced blood platelets and leucocytes, and showed indicators of abnormal liver function.

To determine the likely source of the virus, the research team screened
samples collected from wild animals in the area between 2010 and
2020. They found antibodies for the virus in Hokkaido shika deer and
raccoons. They also found the virus RNA in three major species of ticks
in Hokkaido. Matsuno says, "The Yezo virus seems to have established its distribution in Hokkaido, and it is highly likely that the virus causes
the illness when it is transmitted to humans from animals via ticks."
As the Covid-19 pandemic so dramatically demonstrates, animals carry
many unknown viruses and some of these can go on to infect people. "All
of the cases of Yezo virus infection we know of so far did not turn
into fatalities, but it's very likely that the disease is found beyond Hokkaido, so we need to urgently investigate its spread,"said Matsuno.

The research team now plans to track the possible nationwide distribution
of the novel virus in wild animals and patients. And they say more
hospitals should test for the virus in patients who complain of the
symptoms.

The study was carried out in collaboration with researchers at the
Graduate School of Veterinary Medicine and One Health Research Center of Hokkaido University, Sapporo City General Hospital, Nagaoka Red Cross
Hospital, Hokkaido Institute of Public Health, National Institute of
Infectious Diseases, Nagasaki University, Rakuno Gakuen University,
Health Sciences University of Hokkaido, and the University of Liverpool.

========================================================================== Story Source: Materials provided by Hokkaido_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Fumihiro Kodama, Hiroki Yamaguchi, Eunsil Park, Kango Tatemoto,
Mariko
Sashika, Ryo Nakao, Yurino Terauchi, Keita Mizuma, Yasuko Orba,
Hiroaki Kariwa, Katsuro Hagiwara, Katsunori Okazaki, Akiko Goto,
Rika Komagome, Masahiro Miyoshi, Takuya Ito, Kimiaki Yamano,
Kentaro Yoshii, Chiaki Funaki, Mariko Ishizuka, Asako Shigeno,
Yukari Itakura, Lesley Bell- Sakyi, Shunji Edagawa, Atsushi
Nagasaka, Yoshihiro Sakoda, Hirofumi Sawa, Ken Maeda, Masayuki
Saijo, Keita Matsuno. A novel nairovirus associated with acute
febrile illness in Hokkaido, Japan. Nature Communications, 2021;
12 (1) DOI: 10.1038/s41467-021-25857-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211004104237.htm

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