What is “Langya”, this new virus identified in China, and why is it not worrying?

Researchers have identified a new virus in around 30 people, from 2018 to 2021. Transmission between men seems very limited, and if the symptoms of the disease are severe, the study does not report any cases of death.

A new virus identified in China transmitted by animals? This familiar-sounding story comes from a study published on August 4 in The New England Journal of Medicine. The authors state that they have identified a new virus called Langya henipavirus, or LayV, in 35 patients. Patients have different symptoms: fever, liver dysfunction or nausea. They seem to have been contaminated by animals.

Unlike Covid-19, however, the transmission of this virus seems very limited: the patients studied by the researchers were identified between the end of 2018 and May 2021. We are therefore a long way from the surge of cases that caused, and that still causes. , SARS-CoV-2, as highlighted The Parisian.

A virus from the henipavirus family

This discovery was made as part of a study on patients from three Chinese hospitals, the researchers then recruited patients with a fever above 38°C with “a history of exposure to an animal in the month preceding the illness. “. It was by analyzing samples taken from these patients that they discovered LayV in 35 of them. Of these 35 patients, only 26 – aged between 9 and 84, with a total average age of 57 – were studied by the researchers because they “had no other pathogens”.

LayV is part of the henipavirus family, of which two viruses are known: Hendra and Nipah, two zoonoses. The former is “rare” writes the World Health Organization, but “causes severe and often fatal disease in infected horses and humans.” The identified cases were mostly in Australia.

The second is “present throughout South and Southeast Asia”, writes the Institut Pasteur. “With a mortality rate of more than 70%, this virus is, according to the World Health Organization (WHO), an emerging infectious agent likely to trigger severe epidemics if it were to evolve to gain in transmissibility.”

The study does not mention cases of death for LayV, but nevertheless describes severe symptoms in the 26 patients studied: 100% presented with fever, 54% with fatigue, 50% with cough and anorexia, 46% muscle pain, 38% nausea, 35% headache, vomiting and abnormalities of thrombocytopenia (heavy bleeding), 54% a drop in the number of white blood cells, 35% liver failure and 8% kidney failure.

Infection in the human population appears to be ‘sporadic’

“LayV seems much less deadly” than its cousin viruses, writes on Twitter François Ballouxdirector of the Institute of Genetics at University College London, adding that this virus does not seem to “spread quickly in humans”.

The researchers point out that human-to-human transmission of this virus appears to be limited: “there was no close contact or common history of exposure among patients, which suggests that infection in the human population may be sporadic,” they explain. As a reminder, 35 cases have been identified in three years.

They write, however, that “our sample size was too small to determine the status of human-to-human transmission of LayV.”

At the same time, the study is interested in a possible transmission from the animal, a zoonosis, like the other henipaviruses.

The virus was thus sought in the animals of the patients, the vast majority of whom are farmers, but also in wild animals. 3 goats tested positive out of 168 tested (i.e. 2%), and 4 dogs out of 79 (5%). Among the 25 species of wild animals tested, the virus was mostly found in shrews, with 71 positive individuals out of 262 tested, or 27%.

This finding “suggests that the shrew may be a natural reservoir of LayV,” according to the study authors.

“Further investigation to better understand” this virus

These results “warrant further investigation to better understand the human disease associated” with LayV, the study concludes.

The CDC (Center for Disease Control and Prevention) of Taiwan, after the publication of these results, has already announced that it will create a test to be able to detect this virus and follow its transmission, reports the Taipei Times. The CDC stressed the need to “pay close attention to new updates on the virus.”

“At this point, LayV does not look like a repeat of Covid-19 at all,” writes François Balloux, “but it is still a reminder of the imminent threat caused by the many pathogens circulating in wild animal populations. and domestic animals that have the potential to infect humans.”

Salome Vincendon BFMTV journalist

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