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Dr. Shi Zhengli of the Wuhan Institute of Virology said these viruses, including close relatives of Sars-CoV-2, which causes Covid-19, could circulate in the wild beyond China.
“We should be looking not only in China, but also in South Asian countries,” said Shi, nicknamed the “bat woman” because her research team is studying coronaviruses carried by bats.
His comments, which were made in a webinar organized by French medical and veterinary academies, came as two international teams – one coordinated by the World Health Organization and another set up by the Lancet medical journal – prepare to investigate origins of the pandemic in one year after the official start.
These efforts have become extremely politicized. The United States and China accuse each other of causing the pandemic as their trade war begins to erupt. Other countries, including India, have been named as possible sources. Shi’s lab was accused of being the source of an accidental viral leak earlier this year. There is no evidence to support the accusation and Shi vehemently denied it.
The virologist did not suggest that China should be removed from the investigation, only that these investigations should go beyond China, which they will do.
The natural origin of Sars-CoV-2 is believed to be the bat, and although Shi said the virus was most likely transmitted to another animal before it reached humans, that animal (the intermediate host) has not yet been identified.
Furthermore, it is unclear how long the virus would have circulated in that animal or man before it was detected late last year: Shi said it could have been in one or the other “for a long time” . .
Professor Edward Holmes, a virologist at the University of Sydney, agreed that the virus may have been in an intermediate host for a long time and possibly even in humans a few months before it was reported.
“It’s perfectly possible that the original inter-species broadcast event didn’t happen in Wuhan or around it,” said Holmes, who wasn’t at the webinar.
“It may not even have happened in Hubei province, although of course there are a large number of possible animals that need to be tested to address this problem.”
Shi’s group has so far failed to detect the virus on the farm or in the wild animals they tested around Wuhan, the capital of Hubei province.
He said that if the intermediate host was the pangolin, as some have suggested, the virus could have passed from bats to pangolins outside China, as all pangolins arriving in China are smuggled from other Asian countries. , also from India.
However, prof. David Robertson, who studies viruses at the University of Glasgow, said investigations should remain focused on China.
“We are pretty confident that the pangolins got the virus, probably from the small horseshoe bat, after being imported to China,” said Robertson, who did not attend the webinar.
He said his group’s research indicated that Sars-CoV-2 acquired most of the mutations that made the virus transmissible to humans while it was still in bats.
Those involved in the Lancet and WHO investigations know they may never be able to clarify the exact path the virus took to spread to humans so long after the event.
Their purpose is to identify the ecosystem that made this crossover possible, so as to prevent its recurrence.
Shi’s group reported last year that there are hotspots in China, especially in the south and southwest, where Sars-type coronaviruses have high genetic diversity and therefore a high capacity for change.
The analysis, which the team published in October, indicated that some coronaviruses were already capable of invading human cells – a finding that Shi described as “very surprising.”
Other coronaviruses, linked to the one that caused the Middle East respiratory syndrome (MERS) outbreak in Saudi Arabia in 2012, are circulating in animals in Europe and Africa.
“We believe these viruses have a high risk of inter-species transmission to humans,” Shi said.
Shi called for increased surveillance of two points in the chain where a disease of non-human animal origin becomes human: between wild animals and domestic or farm animals and between farmed animals and humans. Monitoring has recently intensified due to avian influenza outbreaks in British poultry farms, for example.
“On the human side, we clearly need to improve the way we monitor new disease outbreaks,” Robertson said.
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