It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, February 08, 2020
REVENGE Pangolin identified as potential link for coronavirus spread
AFP
The endangered pangolin may be the link that facilitated the spread of the novel coronavirus across China, Chinese scientists said Friday.
Researchers have long suspected that the virus, which has now killed more than 630 people and infected some 31,000, was passed from an animal to a human at a market in the central Chinese city of Wuhan late last year.
Researchers at the South China Agricultural University have identified the scaly mammal as a "potential intermediate host," the university said in a statement, without providing further details.
The new virus is believed to have originated in bats, but researchers have suggested there could have been an "intermediate host" in the transmission to humans.
After testing more than 1,000 samples from wild animals, scientists from the university found the genome sequences of viruses found on pangolins to be 99 percent identical to those on coronavirus patients, the official Xinhua news agency reported.
The pangolin is considered the most trafficked animal on the planet and more than one million have been snatched from Asian and African forests in the past decade, according to the International Union for Conservation of Nature (IUCN).
They are destined for markets in China and Vietnam, where their scales are used in traditional medicine -- despite having no medical benefits -- and their meat is bought on the black market.
- Shadowy wildlife trade -
Experts on Friday called for the Chinese scientists to release more data from their research.
Simply reporting the similarity between the genome sequences of viruses is "not sufficient," said James Wood, a veterinary medicine professor at the University of Cambridge.
Wood said the results could have been caused by "contamination from a highly infected environment."
"We would need to see all of the genetic data to get a feel for how related the human and pangolin viruses are," Jonathan Bell, a professor of molecular virology at the University of Nottingham, said.
China in January ordered a temporary ban on the trade in wild animals until the epidemic is under control.
The country has long been accused by conservationists of tolerating a shadowy trade in endangered animals for food or as ingredients in traditional medicines.
"If we want to do everything in our power to prevent deadly disease outbreaks such as coronavirus, then a permanent ban on wildlife trade, in China, and around the world, is the only solution," said Neil D'Cruze, global head of wildlife research at World Animal Protection.
A price list that circulated on China's internet for a business at the Wuhan market showed a menagerie of animals or animal-based products including live foxes, crocodiles, wolf puppies, giant salamanders, snakes, rats, peacocks, porcupines, camel meat and other game -- 112 items in all.
The SARS (Severe Acute Respiratory Syndrome) virus that killed hundreds of people in China and Hong Kong in 2002-03 also has been traced to wild animals, with scientists saying it likely originated in bats, later reaching humans via civets.
"Working to end the trade in wildlife can help to resolve some of the longer-term risks associated with animal reservoirs of zoonoses," Wood said, referring to infectious diseases that can be passed between animals and humans.
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Pangolin Suspect #1 as direct source of coronavirus outbreak
Researchers at the South China Agricultural University have identified the scaly pangolin as a 'potential intermediate host' for the virus
Chinese researchers investigating the animal origin of the deadly coronavirus outbreak in China said Friday the endangered pangolin may be the "missing link" between bats and humans, but other scientists said the search may not be over.
An earlier study—since discredited—pointed to snakes, and there remain numerous candidate species in the Wuhan wildlife market thought to be ground zero of the epidemic.
The SARS outbreak of 2002-3, involving a different strain of coronavirus, was transferred to humans by the civet, a small mammal prized in China for its flesh.
Missing link: A pangolin?
Many animals are capable of transmitting viruses to other species, and nearly all strains of the coronavirus contagious to humans originated in wildlife.
Bats are known carriers of the latest strain of the disease, which has infected at least 31,000 people and killed more than 630 worldwide, mostly in China where the outbreak originate.
A recent genetic analysis showed that the strain of the virus currently spreading among humans was 96 percent identical to that found in bats.
But according to Arnaud Fontanet, from France's Pasteur Institute, the disease likely didn't jump straight from bats to humans.
"We think there's another animal that's an intermediary," he told AFP.
Several studies have shown that the bat-bourne virus lacks the necessary hardware to latch on to human cell receptors. But it's still not clear which animal is the missing link.
Fontanet believes the intermediary was "probably a mammal," possible belonging to the badger family.
After testing more than 1,000 samples from wild animals, scientists at the South China Agricultural University found the genome sequences of viruses in pangolins to be 99 percent identical to those on coronavirus patients, the official Xinhua news agency reported.
But other experts urged caution.
"This is not scientific evidence," said James Wood, head of the department of veterinary medicine at the University of Cambridge. "Investigations into animal reservoirs are extremely important, but results must be then be published for international scrutiny."
"Simply reporting detection of viral RNA with sequence similarity of 99+ percent is not sufficient," he added.
Wild goose chase?
To conclusively identify the culprit, researchers would need to test each species that was on sale at the market—a near impossibility given that it's now permanently closed.
Martine Peeters, a virologist at France's Institute for Research and Development (IRD), worked on the team that identified the host animal of the Ebola virus during recent epidemics.
Graphic on pangolins, the world's most heavily trafficked mammals.
They found that it was indeed a bat that passed the virus on to humans, and Peeters believes that's likely to be the case this time around.
During her Ebola research, "we collected thousands of bat dropping from several sites in Africa," Peeters told AFP.
Fontanet said that Chinese researchers were doing likewise now.
"They say they've analysed samples from a rubbish truck," he said. "They don't say which, but I think it's likely to have been excrement that was just lying around."
Why does it matter?
While it may be too late for this outbreak, identifying the carrier animal for the novel coronavirus could prove vital in preventing future flare ups.
China for example outlawed the sale of civet for food in the wake of the SARS epidemic.
Eric Leroy, a virologist and vet at the IRD said the search could well turn up a result quickly like in the case of SARS. Equally, it could take years.
"With Ebola, research started in 1976 and we didn't see the first results published until 2005," he told AFP.
One determining factor could be what percentage of the same species are infected.
"If that's low, less than one percent for example, that's obviously going to lower the chance you stumble upon an infected animal," said Leroy.
Prevent future outbreaks?
For Fontanet, coronavirus is just the latest example of the potentially disastrous consequence of humans consuming virus-carrying wild animals.
He said that China needed to "take pretty radical measures against the sale of wild animals in markets."
Beijing has prohibited the practice, but only moved to do so last month, when the outbreak was already out of control.
"Each time, we try to put out the fire, and once it's out we await the next one," said Francois Renaud, a researcher at the Paris-based National Centre for Scientific Research.
He recommended compiling a watch list of all animals that could potentially transmit viruses to humans.
"You need to see epidemics before they come, and therefore you need to be proactive," he said.
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