Zhong Nanshan, head of the high-level expert group of the National Health and Reform Commission and director of the National Center for Clinical Medicine for Respiratory Diseases, said at a special news briefing on epidemic prevention and control organized by the Guangzhou Municipal Government Information Office on February 27, 2020. Although the source of the outbreak is not clear, it has to be said that a series of previous studies on the host of the new coronavirus did show that the “foreign origin theory” is not a hollow wind.
The target is Malaya pangolins, not Chinese pangolins
In fact, people capture pangolins in large quantities and trade illegally to meet their own food and medicinal needs. According to IUCN standards, the protection level of chinese pangolins is at critical (CR). The China Biodiversity Conservation and Green Development Foundation has also declared that Chinese pangolins have become “functionally extinct” in mainland China.
As a result, Malaya pangolins, which live in Southeast Asian countries, were poisoned.
In January 2020, the virological forum noted that, according to the publicly available viral macrogenomic data set, the S1 receptor binding domain of the virus carried by the new coronavirus and Malaya pangolin was 97% similar at 350-530 amino acid residues. It was determined that Malaya pangolins may be the host of the new coronavirus.
Since then, the potential intermediate host of the new corona virus has repeatedly pointed to Malaya pangolins.
On February 7, 2020, South China Agricultural University held a press conference on the study of the outbreak of new coronavirus pneumonia. Shen Yongyi, Xiao Lihua and other researchers from South China Agricultural University and Lingnan Modern Agricultural Science and Technology Guangdong Province Laboratory said at the meeting that pangolins could be potential intermediate hosts for new crown pneumonia.
On February 18, 2020, a paper by the University of Hong Kong’s Management Team and the Hu Yanling Team of Guangxi Medical University was published on bioRxiv, a preprinted website. Pipe and others analyzed and studied three batches of Malaya pangolin samples and found that the amino acid sequence of the new coronavirus and the receptor binding domain of Malaya pangolin coronavirus was as similar as 97.4%. At the same time, Malaya pangolin coronavirus and neo-coronavirus share amino acids on 5 key remnants of the virus receptor region (red box section below).
On February 20, 2020, Professor Shen Yongyi of South China Agricultural University, Lingnan Modern Agricultural Science and Technology Guangdong Province Laboratory, Professor Xiao Lihua’s team and Guangzhou Zoo Research Department published a re-published paper in the preprintbioRxiv, stating that Malaya pangolin is a potential intermediate host for the new coronavirus.
It is worth noting that the team tested tissue samples of 29 smuggled pangolins (4 Chinese pangolins and 25 Malaya pangolins) obtained between March and December 2019 and found a positive rate of 68% (17 / 25) for coronavirus in the Pangolins of Malaya.
At the same time, the consistency of coronavirus genes isolated from Malay pangolins with neo-coronavirus protrusion surface glycoprotein (S), small encapsulation protein (E), matrix protein (M) and nucleocrust protein (N) was 90.4%, 100%, 98.2%, 96.7% respectively. The S-protein receptor binding domain is almost identical to the new coronavirus, with only one amino acid sequence difference.
It can be said that Malaya pangolins mostly carry the virus, but the Chinese pangolin satpan does not – which more or less explains the “epidemic does not necessarily originate in China” view.
Virus Variation and Virus Recombination
There are other sayings about “foreign origintheory”.
On February 20, 2020, the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences published the research results through its official website, saying that the new coronavirus in Wuhan South China Seafood Market was introduced from other places, inferring that the market was not the source of the virus.
It’s worth noting that the study also mentions that the number of cases of proliferation comes from at least three pathways.
To subdivide the source, the researchers divided 58 monosizes (several gene types that determine the close-knit genetic composition of the same trait) into five groups, using criteria of three centers (old super-transmitters) of the monodox (H1, H3 and H13) and two new super-transmitters (H56 and mv2). H56 is also the source of infection for patients in Australia, France and the United States, as well as in Taiwan. Patients in other countries because of the relatively small samples, most of the source is relatively single, in addition to Wuhan tourism input or infection in Wuhan, some people may be infected in Guangdong, Singapore and other places.
In fact, relevant background people also said that there may be the possibility of the virus originating elsewhere, in Wuhan mutation.
In addition, in 2017, Shi Zhengli’s team had a study showing that the coronavirus carried by bats could directly infect people. In a paper published on January 23, 2020, Shi Zhengli’s team noted that the new coronavirus is 96.2% consistent with the coronavirus carried by bats throughout the genome.
Based on this, there is also a “viral recombination” of the term – including two inferences, one is that the bat-carrying coronavirus and Malaya pangolin-carrying coronavirus in the middle host occurred, and the other is the bat coronavirus directly infected people.
It is worth mentioning that although the above inference is based on a series of previous expert research results, but it does not fully explain that the new coronavirus originated abroad.