More surveillance is needed on a new virus found in dozens of people in eastern China that may cause another pandemic and suggests how easily viruses can spread undetected from animals to humans, scientists say.
Researchers say China conceals the spread of many deadly viruses until they mass spread within the country. China’s reluctance in reporting the deadly viruses to international community and the UN, may again cause a global pandemic soon.
The virus, called Langya henipavirus, has infected nearly three dozen farmers and other residents, according to a team of scientists who believe it may have spread to humans directly or indirectly from shrews — small, mole-like mammals found in a wide range of habitats.
The pathogen has caused no reported deaths, but was detected in 35 patients with fever in hospitals in Shandong and Henan provinces between 2018 and 2021, a finding consistent with scientists’ long-standing warning that animal viruses regularly spread undetected. to people all over the world.
“We greatly underestimate the number of these zoonotic disease cases in the world, and this (Langya virus) is just the tip of the iceberg,” said new virus expert Leo Poon, a professor at the University of Hong Kong’s School of Public Health. who was not involved in the latest study.
The first scientific research on the virus, published as a correspondence by a team of Chinese and international researchers in the New England Journal of Medicine last week, has gained global attention amid heightened fears of an outbreak. Hundreds of thousands of new cases of Covid-19 are still being reported around the world every day, nearly three years since the novel coronavirus behind the pandemic was first detected in China.
However, scientists say there is no evidence that the Langya virus is spreading between humans or that it has caused local outbreaks of related cases. More studies are needed in a larger subset of patients to rule out human-to-human spread, they added.
Veteran infectious disease scientist Linfa Wang, who was part of the research team, told CNN that while the new virus is unlikely to evolve into “another ‘disease X,’ such as a previously unknown pathogen that sparks an epidemic or pandemic,” it shows that such zoonotic spillovers occur more frequently than we think or know.”
To reduce the risk of an emerging virus becoming a health crisis, “it is absolutely necessary to conduct active surveillance in a transparent and internationally cooperative manner,” said Wang, a professor at the Duke-National University of Singapore Medical School.
Tracking a new virus
The first signs of the new virus came when a 53-year-old farmer sought treatment at a hospital in Qingdao city in Shandong province in December 2018 with symptoms including fever, headache, cough and nausea, according to documentation from the researchers.
Because the patient reported having been in contact with animals in the past month, she was included in another screening conducted at three hospitals in eastern China aimed at identifying zoonoses.
When the patient’s test samples were examined, the researchers found something unexpected – a never-before-seen virus related to the Hendra and Nipah viruses, highly lethal pathogens from a family not usually known for easy human-to-human spread.
Over the next 32 months, researchers at three hospitals screened similar patients for the virus and eventually detected it in 35 people who, in addition to fever, had a range of symptoms including cough, fatigue, headache and nausea.
Nine of these patients were also infected with a known flu-like virus, so the source of their symptoms was unclear, but the researchers believe that the symptoms in the remaining 26 may have been caused by the new henipavirus.
Some showed serious symptoms, such as pneumonia or abnormalities in thrombocytopenia, a platelet condition, according to Wang, but their symptoms were far from those seen in Hendra or Nipah patients, and none of the group died or were admitted to the ICU. While all recovered, they were not being followed up for longer-term problems, he added.
Of that group of 26, all but four were farmers, and while some were identified by the same hospital as the first case detected, many others were found in Xinyang, more than 700 kilometers (435 miles) away in Henan.
Because similar viruses were known to circulate in animals from southwest China to South Korea, it was not “unsurprising” to see spillover to humans over such long distances, Wang explained.
Wang and his colleagues wrote in their findings “no close contact or common history of exposure between patients” or other signs of human-to-human spread. This suggests the cases were sporadic, but more research was needed, they said.
Once they knew the new virus was infecting humans, scientists, which included Beijing scientists and disease control officials in Qingdao, began working to see if they could discover what was infecting the patients. They tested the domesticated animals where the patients lived for traces of past 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 shrews, leading scientists to believe that these small rodent-like mammals could be where the virus naturally circulates.
What remains unclear is how the virus entered humans, Wang said.
Further screening studies for Langya henipavirus will follow and should be conducted not only in the two provinces where the virus was found, but more broadly in China and beyond, he said.
China’s National Health Commission did not immediately respond to a request for comment on whether new virus infections were being monitored.
Risk reduction
Globally, 70% of emerging infectious diseases are thought to have passed to humans through contact with animals, a phenomenon scientists say has accelerated as the growing human population expands into natural habitats.
China has seen major outbreaks of emerging viruses in the past two decades, including SARS in 2002-2003 and Covid-19 – both first detected in the country and from viruses believed 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 – show the importance of quickly identifying cases of new viruses and sharing information about potential risks.
Scientists who were not involved in the new research agreed that more work is needed to understand the Langya virus and confirm the latest findings, and said the discovery underscores the importance of tracking which viruses can spread from animals to humans.