The mystery behind the animal origins of the new coronavirus called 2019-nCoV continues to deepen as recent evidence points toward the critically endangered pangolins — ant-eaters — whose scales are illegally used in traditional Chinese medicines.
When a team of scientists compared the genes of pangolin coronavirus with the new human coronavirus, they found a whopping 99% match. The team announced these findings during a press briefing and are yet to publish them.
“This is an extremely interesting observation. Although we need to see more details, it does make sense as there are now some other data emerging that pangolins carry viruses that are closely related to 2019-nCoV,” Edward Holmes, an evolutionary virologist at the University of Sydney, Australia, told Nature.
Why is it important to identify the animal source?
The new human coronavirus is a zoonotic virus, meaning some animal has transferred the virus to humans. Figuring out the animal source could help health experts contain the infection that has sickened over 40,000 people and killed over 900.
This points to a scenario where pangolins may have consumed food already contaminated with the feces or saliva of an infected bat. And humans, in turn, may have consumed the infected pangolins, allowing the virus to jump to humans. But so far scientists have not been able to conclusively prove the animal source, thanks to the shutting down of the Hunan seafood market. Without testing each species that was on sale at the market, scientists will have to now rely on reading and comparing genes of various viruses from different animals.
Bats and an intermediary host
Previous studies indicate that the original animal source could be bats. The human coronavirus is most closely related to two other coronaviruses whose animal origins can be traced to bats — these mammals are also thought to be the natural host of Ebola virus, rabies, SARS, and MERS.
But there is a catch: Wuhan coronavirus and the bat-derived coronaviruses were only 90% identical, which suggests that the virus from bats may have infected another animal before moving on to humans.
“We know a fair amount of viruses on the World Health Organization’s (WHO) Blueprint list of priority diseases have either a direct or indirect link with bats,” Vincent Munster, a virologist at Rocky Mountain Laboratories, told Business Insider.
Scientists are on a hunt to track down the missing link: the intermediary animal hosting the virus, which shares a higher degree of genetic similarity with the new coronavirus.
With new evidence on pangolins, scientists are optimistic. “I can believe it could be true,” Kristian Andersen, an immunologist and computational biologist at Scripps Research in La Jolla, California, told Nature. Andersen says he has compared publicly available sequences of pangolin viruses and found that they are similar to that of nCoV-2019. “I look forward to the published report and data.”
