Researchers argue that the new Langya virus discovered in China is the “tip of the iceberg” for undiscovered pathogens.
A new virus detected in dozens of people in eastern China needs more monitoring, scientists say, not causing the next pandemic but showing how easily viruses can slip unnoticed from animals to humans.
Virus, nickname Longya henipavirusNearly three dozen farmers and other residents have been affected, according to a team of scientists who believe it may have spread to people directly or indirectly from shrews — small, mole-like mammals found in a variety of habitats.
There have been no recorded deaths from the pathogen, but between 2018 and 2021 it was diagnosed with an unrelated fever in 35 patients at hospitals in Shandong and Henan provinces, scientists said — a finding consistent with scientists’ long-standing warnings about those animal viruses. People around the world continue to spread undetected.
“We greatly underestimate the number of these zoonotic cases in the world [vírus Langya] This is only the tip of the iceberg,” said emerging virologist Leo Poon, a professor at Hong Kong’s School of Public Health, who was not involved in the latest study.
The first scientific study of the virus was published in a letter from a team of Chinese and international researchers In New England Journal of Medicine Last week, it gained worldwide attention due to increased concern about disease outbreaks. Nearly three years after the novel coronavirus behind the pandemic was first identified in China, millions of new Covid-19 cases continue to be reported every day around the world.
However, researchers say there is no evidence that Longya virus can spread between people. They added that further studies on a larger subset of patients are needed to rule out human-to-human transmission.
Lingfa Wang, a senior emerging infectious disease scientist who was part of the research team, told CNN that while the new virus is “unlikely to evolve into another ‘Disease X’ event, when it triggers a previously unknown epidemic or pandemic, it is “more likely that this kind of zoology is more than we think or know. demonstrates that diffusion events occur more frequently”.
To reduce the risk of the emerging virus becoming a public health crisis, “proactive surveillance, with transparent, international cooperation, is absolutely essential,” said Wang, a professor at the Duke-National Singapore School of Medicine. .
Follow the new virus
The first clues to the presence of the new virus were found in December 2018 when a 53-year-old farmer was treated at a hospital in Qingdao, Shandong province, with symptoms including fever, headache, cough and nausea. Documents.
Because the patient indicated that he had contact with animals in the previous month, he was included in additional screenings at three hospitals in eastern China, focusing on the detection of zoonotic diseases.
When testing samples from this patient, the scientists found something unexpected – a never-before-seen virus related to the Hendra and Nipah viruses, highly dangerous pathogens from a family not generally known to spread easily from person to person.
Over the next 32 months, researchers at three hospitals tested the virus in similar patients, eventually finding it in 35 people who had a range of symptoms including cough, fatigue, headache and nausea.
Nine of those patients were infected with a known flu-like virus, so the source of their symptoms is unclear, but the researchers believe the remaining 26’s symptoms may have been caused by the new henipavirus.
Some had severe symptoms such as pneumonia or thrombocytopenia, a platelet-related condition, but their symptoms were severe compared to those seen in the Hendra or Nipah patients, and no one in the group died or was admitted to intensive care units. He added that all had recovered and were not being monitored for long-term problems.
Of that group of 26, all but four were farmers, and while some were reported by the same hospital where the initial case was diagnosed, many others were found in Sinyang, 700 kilometers away in Henan.
Wang explained that since similar viruses are known to spread in animals from southwest China to South Korea, it is “not surprising” to see them spread over such long distances in humans.
“There was no common contact or exposure history among patients” or other signs of human-to-human transmission, Wang and his colleagues wrote in their findings. They said the cases were sporadic, but needed further investigation.
Once they learned that a new virus was infecting people, the researchers, which included Beijing-based scientists and Qingdao disease control officials, began to see if they could figure out what was infecting the patients. They tested livestock where the patients lived for traces of past infection with the virus, and found that a small number of goats and dogs may have previously had the virus.
But the real breakthrough came when they tested samples taken from small wild animals caught in traps — and found 71 infections in two species of shrews, leading scientists to suggest that these small, wild-animal-like mammals may be where the virus naturally spreads.
It’s not yet clear how people got the virus, Wang said.
Other Langya henipavirus screening studies will follow, Wang said, not only in the two provinces where the virus was detected, but widely within and outside China.
China’s National Health Commission did not immediately respond to a request for comment on whether it is controlling new infections of the virus.
Risk reduction
Globally, 70% of emerging infectious diseases are thought to have been transmitted to humans through contact with animals, a phenomenon scientists say has been accelerated by the expansion of human populations into wildlife habitats.
China has seen major outbreaks of emerging viruses over the past two decades, including SARS and Covid-19 in 2002-2003 — viruses first identified in the country and thought to have originated in bats.
The devastating effects of both diseases — especially Covid-19, which has killed more than 6.4 million people worldwide to date — demonstrate the importance of quickly identifying cases of new viruses and sharing risk information.
Scientists who were not involved in the new research acknowledged that more work is needed to understand Langya virus and confirm the latest findings, and said the discovery underscores the importance of monitoring which viruses can spread from animals to people.
“Since it (the new henipavirus) may not be confined to China, it is important to share this information and allow others to prepare or do more research in their own countries,” Boon said in Hong Kong.
Scientists say it’s important to answer important questions about the size of the new virus in nature, how it spreads between people and how dangerous it is to human health — including its potential to spread between people or acquire this ability if it persists. From animals to humans.
The geographic scale of where infections have been detected “suggests that the risk of this infection is very widespread,” said Malik Peiris, a virologist at the University of Hong Kong, adding that studies in other parts of China and in neighboring countries are important. Geographic breadth of this virus in animals (shrews) and humans”.
Recent findings point to the number of undiagnosed infections that can be transmitted from wildlife to humans, and systematic studies are needed to understand not only this virus but also the broader picture of human infection with the virus, Peiris said.
“It’s important that we’re not surprised by the next pandemic, when — not if — it comes,” he concluded.
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