Researchers said the new Lanjia virus found in China may be the “tip of the iceberg” for undetected pathogens.
Scientists said more monitoring is needed for a new virus discovered in dozens of people in eastern China, which may not cause the next epidemic, but shows how easily viruses can go unnoticed from animals to humans.
Virus aka Langia Hanibahas infected nearly 36 farmers and other residents, according to a team of scientists who believe it may have spread directly or indirectly to people from shrews — small, mole-like mammals found in a variety of habitats.
The pathogen did not cause any recorded deaths, but was detected in 35 patients with unrelated fevers in hospitals in Shandong and Henan provinces between 2018 and 2021 — a finding that is in line with scientists’ longstanding warnings about the animal viruses, the scientists said. It regularly leaks to people all over the world undetected.
“We are dramatically underestimating the number of these zoonotic cases in the world, and this [vírus Langya] “It’s just the tip of the iceberg,” said emerging virologist Liu Bun, a professor at the University of Hong Kong’s School of Public Health, who was not involved in the latest study.
The first scientific investigation of the virus, published as correspondence from a team of Chinese and international researchers In the New England Journal of Medicine Last week, it gained global attention due to growing concern about disease outbreaks. Hundreds of thousands of new Covid-19 cases continue to be reported around the world every day, for nearly three years since the new coronavirus behind the epidemic was first discovered in China.
However, the researchers say there is no evidence that the Langia virus is spreading between people or that it has caused a local spread of related cases. They added that more studies on a larger subset of patients are needed to rule out human-to-human spread of the disease.
Linfa Wang, a veteran emerging infectious disease scientist who was part of the research team, told CNN that while the new virus is unlikely to develop into another “disease X” event, such as when a previously unknown person causes a pandemic or pandemic. This “demonstrates that such zoonotic outbreaks occur more often than we think or know.”
In order to reduce the risk of an emerging virus turning into a health crisis, “it is absolutely necessary to conduct active surveillance, in an internationally transparent and collaborative manner,” said Wang, a professor at Duke National University School of Medicine in Singapore.
Follow new virus
The first signs of the new virus came when a 53-year-old farmer sought treatment at a hospital in Qingdao, Shandong Province, in December 2018 with symptoms including fever, headache, cough and nausea, according to the researchers. documentation.
Since the patient indicated she had had contact with animals in the previous month, she was enrolled in additional examinations being performed at three hospitals in eastern China, focused on identifying zoonoses.
When examining test samples from this patient, the scientists found something unexpected – a never-before-seen virus linked to Hendra and Nipah viruses, highly lethal pathogens from a family not usually known for how easily they spread from human to human.
Over the next 32 months, researchers at the three hospitals tested this virus in similar patients, eventually finding it in 35 people, who developed a combination of symptoms, including coughing, fatigue, headaches and nausea, as well as fever.
Nine of those patients also had a known virus, such as influenza, so the source of their symptoms was not clear, but researchers believe that symptoms in the remaining 26 may be caused by the new HHNiba virus.
Some had severe symptoms such as pneumonia or abnormalities of thrombocytopenia, a condition associated with platelets, according to Wang, but their symptoms were severe compared to those seen in Hendra or Nipah patients, and neither group died or was admitted to care. intensive units. He added that all of them recovered and were not monitored for long-term problems.
Of that group of 26 people, all but four were farmers, and while some were reported by the same hospital where the initial case was discovered, many were found in Xinyang, more than 700 kilometers away in Henan.
Wang explained that since similar viruses are known to circulate in animals from southwest China to South Korea, it was “not surprising” to see spread between humans taking place over long distances.
“There was no close contact or a common history of exposure among patients” or other signs of human-to-human spread of the virus, Wang and colleagues wrote in their findings. They said this indicates that the cases have been sporadic, but that more investigation is needed.
Once they learned that a new virus was infecting people, researchers, including scientists from Beijing and disease control officials in Qingdao, began working to see if they could figure out what was infecting patients. They tested pets where patients lived for traces of previous infection with the virus, and found a small number of goats and dogs that may have had the virus previously.
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 shrew, leading scientists to suggest that these small, wild animal-like mammals could be where the virus naturally spreads.
What remains unclear, Wang said, is how the virus reached people.
Wang said that more screening studies for Langia henipa virus will follow, which should be conducted not only in the two provinces where the virus has been detected, but more widely inside and outside China.
China’s National Health Commission did not immediately respond to a request to comment on whether control of new infections with the virus was underway.
risk reduction
Globally, 70% of emerging infectious diseases are thought to have passed to humans through contact with animals, a phenomenon that scientists say has accelerated as human populations expand into wildlife habitats.
China has had major outbreaks of emerging viruses over the past two decades, including SARS in 2002-2003 and Covid-19 – both first discovered in the country and viruses believed to have originated in bats.
The devastating effects of both diseases – notably Covid-19, which has so far killed more than 6.4 million people worldwide – show the importance of quickly identifying new virus cases, and sharing information on risks and possibilities.
Scientists not involved in the new research agreed that more work was needed to understand the Langia virus and confirm the latest findings, and said the discovery underlined the importance of tracking viruses that may spread from animals to humans.
“Because (the new Haniba virus) may not only be circulating in China, it is important to share this information and allow others to set up or do more research in their own countries,” Boon said in Hong Kong.
Scientists say it is necessary to answer important questions about how widespread the new virus is in nature, how it spreads between humans and how dangerous it is to human health – including the possibility of spreading between people or gaining this ability if it persists. From animals to humans.
Virologist Malik Peiris, also of the University of Hong Kong, said that the geographical range of where infections were detected “indicates that this risk of infection is widespread,” adding that studies in other parts of China and neighboring countries were important “to determine the geographical breadth of this virus in animals (shrews). ) and humans.
Peiris also said that the recent findings indicate the large number of undetected infections transmitted from wildlife to humans, and the need for systematic studies to understand not only this virus, but also the broader picture of human infection with the virus in wildlife.
“This is important so that we are not surprised by the next epidemic, when – not if – it comes,” he concluded.
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