Who is the “responsible culprit” of the new corona virus? Bat? Pangolin? From the beginning of the new coronaoutbreak, to the present cumulative number of confirmed cases in the world of more than 3.83 million, the question remains unanswered. Recently, Chinese researchers have given the latest answer: the new coronavirus may be produced by pangolin coronavirus and bat coronavirus recombination!
On 7 May 2020, local time, the research team from the Institute of Veterinary Medicine of South China Agricultural University, Lingnan Modern Agricultural Science and Technology Guangdong Province Laboratory (including its Zhaoqing Sub-Center), Guangzhou Zoo, China Agricultural University School of Biological Sciences, National Key Laboratory of Agricultural Biotechnology, and Guangdong Wildlife Rescue Center published an online study entitled Isolation of SARS-CoV-2-corona virus from The World. Malayan pangolins (separation of the new coronavirus-related coronavirus in Malaya pangolins).
Whose pot is it?
The intermediate host of the new coronavirus may be a bat.
During the outbreak, the last string of English we should not feel strange is undoubtedly SARS-CoV-2, the international generic name for the new coronavirus.
Lei Feng reported earlier that the international scope of the naming of viruses by the International Virus Classification Committee responsible for the global epidemic of the new coronavirus was named SARS-CoV-2 by the International Virus Classification Committee, the reason is that the new coronavirus SARS-CoV-2 and many years ago the “SARS” virus SARS-CoV relationship – there is a clear difference between the two, SARS-V-2 has its novel nature, but at the same time the two belong to the same type, affinity.
Long before the outbreak, researchers discovered that the SARS-CoV strain of the SARS virus originated in bats.
So along this line of thinking, as a relative of SARS virus, the culprit of the new corona virus will also be bats?
As early as January 23, 2020 local time, the Chinese Academy of Sciences Wuhan Virus Institute Shi Zhengli team published a paper on the preprinted website bioRxiv, the new coronavirus’s intermediate host may be bats.
Specifically, the team obtained the entire genome of the SARS-CoV-2 virus from five patients and found that the genomes of the five cases were essentially the same. SARS-CoV-2 was 96.2% consistent across the genome with the coronavirus Bat-CoV-RaTG13 detected in The Chinese chrysanthemum manta rays in Yunnan, and 79.5% consistent with SARS-CoV.
After peer review, the paper was subsequently published in the journal Nature on February 3, 2020, local time.
The intermediate host of the new corona virus may be pangolins
However, the charm of science lies in constant exploration, new discoveries, and the overthrow or corroboration of the views of previous people.
On February 7, 2020, South China Agricultural University held a press conference on the study of the outbreak of new coronavirus pneumonia. At the meeting, South China Agricultural University, Lingnan Modern Agricultural Science and Technology Guangdong Province Laboratory Shen Yongyi, Xiao Lihua and other researchers said that pangolins may be the potential intermediate host of the new coronavirus.
It is understood that the team this conclusion of the process, mainly divided into four steps:
First, by analyzing more than 1000 macro genome samples, the pangolin is identified as a potential intermediate host;
Secondly, through molecular biology testing, it is revealed that the positive rate of beta-coronavirus in pangolins was 70%.
Subsequently, the virus was further isolated and identified, and the typical coronavirus particle structure was observed under the electric mirror.
Finally, through genomic analysis of the virus, it was found that the isolated strains were 99% similar to the sequence of the current infected humans.
After that, a research team led by leading virologist Guan Yu has once again proved that pangolins are the intermediate hosts of the new coronavirus – On February 18, 2020, the University of Hong Kong’s Management Team and the Hu Yanling team of Guangxi Medical University published a publication on the preprinted site bioRxiv entitled Identifi of 2019-nCoV coronaviruses in Malayanpangolins in China (Identification of Coronary Virus in Malaya Pangolin in Southern China 2019-nCov Related to Coronavirus).
According to lei Feng.com (public number: Lei Feng.) at the time, researchers analyzed and studied three batches of pangolin samples — 18 frozen pangolins (lungs, intestines) seized by Guangxi Customs in an anti-smuggling operation between August 2017 and January 2018 43 tissue samples, including blood) and 19 samples of 12 pangolins (9 intestinal tissues, 10 lung tissues) from May-July 2018, 5 seized by the Guangzhou Customs Technology Center in the Anti-Smuggling Operation in March 2019 Archive pangolin samples (2 skin swabs, 1 unknown tissue, 1 scale).
The results show that:
The similarity of the coronary virus Pangolin-CoV genome found in pangolin samples to the SARS-CoV-2 genome was 85.5%-92.4%;
The amino acid sequence similarity of SARS-CoV-2 with Pangolin-CoV receptor binding domain was as high as 97.4%, while the amino acid similarity with the Bat-CoV-RaTG13 receptor binding domain was only 89.2%.
Pangolin-CoV and SARS-CoV-2 share amino acids on five key residues in the virus receptor region, while Bat-CoV-RaTG13 shares only one amino acid with SARS-CoV-2.
As a result, pangolins are more likely to be the intermediate host of the new coronavirus than bats.
Also after peer review, the paper was finally published in the journal Nature on March 26, 2020, local time.
New coronavirus or cogeneration of two coronaviruses
Lei Feng network learned that in 2003 the pipe team took the lead in isolating the SARS virus, confirming that the fruit beaver was its intermediate host and a direct source of human infection with SARS, and then reported together with Zhong Nanshan academician, which played a key role in containing the outbreak at that time.
However, although Professor Guan Qi has made great achievements in the field of virology, the process of finding the source of the new coronavirus has not come to an end.
Recently, the team led by South China Agricultural University gave a new answer again in the paper.
Specifically, the researchers isolated a coronavirus, pangolin-CoV, from 17 of the 25 Malaya pangolin samples and found that:
The E, M, N and S genes of Pangolin-CoV are homologous to SARS-CoV-2, respectively, at 100%, 98.6%, 97.8% and 90.7%;
The receptor binding domain within the Pangolin-CoV S protein is actually the same as the receptor binding domain of SARS-CoV-2, with only one non-critical amino acid difference.
The image above shows the genomic representation of Pangolin-CoV.
Based on these findings, the researchers say SARS-CoV-2 may have been the result of a reorganization between Pangolin-CoV and Bat-CoV-RaTG13.
In addition, the researchers showed possible pathological changes in pangolin-CoV-induced pangolin lungs.
As shown in the figure below, part a is negative (healthy), b, c, and d are all infected with Pangolin-CoV, showing the proliferation and desperation of alveolar epithelial cells and ferroous hetrinophin pigment, where c has severe capillaries. In addition, e is a transmission electron microscope image of the lung tissue double-film cystic bubble, with coronavirus clearly visible in the upper right corner.
In fact, the paper also explicitly mentions:
Pangolins are the most trafficked mammals, and if the wildlife trade is not effectively controlled, the coronavirus may also pose a threat to public health in the future.
While this conclusion may not be the final answer, it also provides new ideas for finding the source of the new coronavirus. We look forward to the early surface of the “truth” and the outbreak to end as soon as possible.