What is known about Langya henipavirus, a new virus identified in China

What is known about Langya henipavirus, a new virus identified in China

  • Mariana Albim
  • From BBC News Brazil in Sao Paulo

Aug 9, 2022, 11:16 p.m. 03

Updated 7 hours ago

Elderly man in a mask sitting is examined by a female doctor

Credit, Getty Images

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Cases of infection with the new virus have been detected in patients admitted to hospitals in China with a fever

A new virus of this kind henipavirus, a group known to have caused outbreaks of highly deadly human infections, scientists revealed last Thursday (4/8). According to the research team, the virus called Langya henipavirus (LayV) caused infections in at least 35 people in China between 2018 and 2021.

The 35 cases were discovered and analyzed over the years, but they have only now been described in the scientific journal The New England Journal of Medicine. Of these, 26 cases were analyzed in detail it was shown that 100% of the patients had fever and some other symptoms such as tiredness (54%), cough (50%), headache (35%), vomiting (35%) ). There were also some abnormalities in liver (35% of patients) and kidney (8%) function. There is no information on fatalities.

According to the researchers, there is no evidence of transmission of LayV through facetoface contact. The source of the infection is likely an animal scientists say there is evidence that the shrew is a natural reservoir of the langya, but this has yet to be confirmed by further studies. Experts assure that the detection of the new virus is far from signifying a new pandemic.

However, the discovery of a virus belonging to the genus Henipavirus is worrying, as other pathogens from this group have already caused outbreaks and serious infections in Asia and Oceania, mainly LayV’s cousins ​​called Hendra henipavirus (HeV) and Nipah henipavirus (NiV). Hendra henipavirus (HeV) infection is rare, but the mortality rate is as high as 57%, according to the US Centers for Disease Control (CDC). In outbreaks of Nipah henipavirus (NiV) reported between 1998 and 2018, the fatality rate ranged from 40% to 70% of infections. Both cause respiratory and neurological problems.

It is difficult to compare this data with the mortality rate of the coronavirus that causes the current pandemic, due to different methods and different numbers depending on the country and time period. However, it can be said that the lethality of Hendra and Nipah viruses in the outbreaks that have occurred has been significantly higher than that of the coronavirus in the current pandemic.

Virologist Jansen de Araujo, professor and researcher at the Laboratory for the Study of Emerging Viruses at the University of São Paulo (USP), emphasizes that the detection of the Langya virus is far from being a harbinger of a pandemic.

“What was observed does not mark a hot spot (something like a ‘transmission hotspot’) as in the case of the coronavirus, in which the virus was found and soon spread very rapidly throughout the region,” Araujo recalls. The researchers who studied the Langya Identified henipavirus, monitored the cases over a long period of time.

“The new virus also did not show very rapid efficient humantohuman transmission. But as a pathogenic virus (causing disease) it is necessary to be vigilant and monitor new cases.”

Araujo, USP’s Doctor of Microbiology, also points out that the high lethality of Hendra and Nipah viruses may have slowed their transmissibility.

“Very deadly viruses like Ebola have low spread because they kill people faster than they transmit them,” he explains. “If you have a virus that causes greater severity, the odds of it spreading are reversed.”

The presence of the virus has never been confirmed in Brazil, the researcher says

Araujo is part of the National Wildlife Surveillance Network (Previr) project and has been searching for signs of henipavirus in Brazilian soil for several years. In 2017, he and colleagues published a paper with evidence that bats found in Brazil could be natural reservoirs of Nipah, but this could not be confirmed with the evidence collected. According to the researcher, no case of Hendra or Nipah infection in humans has been confirmed in Brazil either.

In the New England Journal of Medicine publication that revealed Langya henipavirus, all of the infected patients were residents of Shandong and Henan provinces. They had no close contact with each other and no past in which they traversed the same places. The researchers traced contacts between nine patients and their loved ones and found no infections that could demonstrate humantohuman transmission.

More than half of those infected were farmers, which is relevant considering the virus reached people through some form of contact with animals.

The researchers looked for molecular traces of langya in domestic and wild animals, and the shrews showed the highest percentage detection of the virus. Therefore, the researchers say it may be the pathogen’s natural reservoir, although they recognize that in the study they failed to meet the socalled Koch postulates, which demonstrate causality between a pathogen and the disease.

Credit, Getty Images

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Of the wild and domestic animals studied, the shrew had the highest presence of the virus.

For Jansen de Araujo, it would be desirable to specifically analyze samples from giant bats in search of langya, since these are known reservoirs of the Hendra and Nipah viruses but the animals infected with a virus are considered “natural reservoirs”, explains the researcher without developing disease. The definitive hosts, on the other hand, become infected and develop Hendra infection, as in horses and humans.

The reported cases of Nipah have occurred through direct human contact with infected bats and pigs; with the sap or sap of date palms infected with bat droppings; or even in personal contact.

Veterinarian Michele Lunardi, PhD in animal virology at the State University of Londrina (UEL), published an article with colleagues in 2021 discussing studies on henipaviruses. According to the authors, “HeV and NiV are highly lethal viruses with repeated resurgence and without any prophylaxis or therapies approved for human use.” NiV, in particular, has “the ability to unleash a devastating pandemic,” the article said.

In an interview with BBC News Brazil, Lunardi points out that the scientists who identified Langya henipavirus did so through routine surveillance of febrile cases in China a measure they see as fundamental to preventing the spread of this and other viral diseases designated.

“Febrile patients appear to be treated in select hospitals in China and, if they report previous animal contact, samples are collected for metagenomic analysis. These are powerful tools for identifying pathogens,” explains the veterinarian.

“This type of active surveillance with new (genetic) sequencing tools is extremely important considering that these potentially zoonotic that is, animaltohuman infectious agents will become new pandemic agents in the future.”

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