Recently, the outbreak of the new coronavirus pneumonia outbreak is grim. Judging from the results of only a few direct studies at present, there are many opinions on the source, route and pathogenesis of the virus that caused the epidemic infection, and since the genetic sequence of the new coronavirus, the speculation results of many colleges and universities on the source of the virus are inconsistent.
On January 23, Shi Zhengli's team at the Wuhan Institute of Virology, Chinese Academy of Sciences, confirmed that the Wuhan novel virus was a coronavirus and named nCoV-2019 by comparing the sequence of the molecular marker gene (conserved gene) used to identify the coronavirus, and found that the virus had a 96.2% agreement with the bat coronavirus RaTG13 previously detected on rhinolophus affinis in Yunnan. It is speculated that the nCoV-2019 virus originated in bats.
On January 24, Zhu Huaiqiu, a professor in the Department of Biomedical Engineering at Peking University's School of Engineering, suggested that bats and mink may be two potential hosts for the new coronavirus, of which mink may be intermediate hosts.
On January 26, the Institute of Virology of the Chinese Center for Disease Control and Prevention detected 33 samples of 585 environmental samples from the Huanan Seafood Market in Wuhan containing the nucleic acid of the novel coronavirus, suggesting that the virus originated from wild animals sold in the Huanan Seafood Market, but the study did not identify which animal it was.
Obviously, the current research results do not give the exact source of the nCoV-2019 virus, but some netizens and self-media can't wait to recognize bats as the "culprit" of this infectious disease, and randomly accompanied by various bat pictures, and most of them have no specific species name information, and even call for "extinction of bats".
First of all, it is clear that the prevention and control of the epidemic is still the top priority. Leaving aside the current research conclusions that speculate that bats are the natural hosts of the nCoV-2019 virus, there are still many chains of evidence that are lacking, even if bats alone are difficult to do. We carefully analyzed the association between the nCoV-2019 virus that caused this outbreak and bats with the results of the existing scientific research.
First, scientists have sequenced and analyzed the genome of the new virus that caused the outbreak of the epidemic, and confirmed that nCoV-2019 belongs to the coronavirus by comparing the molecular marker gene (conserved gene) sequence used to identify the coronavirus, and at the same time constructed a coronavirus phylogenetic tree based on the conservative gene sequence, the results showed that the nCoV-2019 virus is closely related to the SARS coronavirus, and previous studies have confirmed that the natural host of the SARS virus is bats. Rhinolophus sinicus, but the most recently related to the coronavirus carried by a middle chrysanthemum bat (Rhinolophus affinis) from Yunnan, has a genome similarity of up to 96.2%, based on the above results Scientists speculate that the nCoV-2019 virus that caused the outbreak originated in bats.
Rhinolophus sinicus
1) Available results and background knowledge (the origin of the coronavirus can mostly be traced back to bats) There is reason to speculate that the nCoV-2019 virus originated in bats. note! Here originated from bats, not arbitrarily directly from bats, because we know that many viruses have an obligate natural host, and transmission requires an intermediate host, so where are bats in the process of nCoV-2019 transmission, is it the source? Or an intermediate host? More evidence is needed to judge.
2. Why is it widely reported in the media that the source of infection for nCoV-2019 is the Chinese chrysanthemum bat instead of rhinolophus affinis? Obviously, the coronavirus carried by the Chrysanthemum Bat is most similar to nCoV-2019, so why is the publicly reported source of infection the Chinese Chrysanthemum Bat? The two are obviously different in terms of body shape and facial nasal lobe structure.
Rhinolophus affinis
3. From the perspective of the previous spread of SARS coronavirus, the infection from Chinese chrysanthemum bat to human needs an intermediate host, which depends on the exclusive host characteristics of the virus. The virus in the bat body only spreads in the bat taxon most of the time, and is not contagious to other animals and people, but once the ecological balance is destroyed or the living environment is disturbed, the bat leaves the original habitat, spreads to the human activity area, and comes into contact with humans or domestic animals, the virus will likely cross the boundaries of the species to mutate, making it susceptible to humans, which is why humans can be exposed to bat viruses.
4. It should be emphasized that even if it is now speculated that the nCoV-2019 virus originated in bats (mid-chrysanthemum bat) or wild animals such as snakes and minks, more evidence is needed to confirm it. For example, more species and individual samples are used to screen the source and intermediate host of the nCoV-2019 virus, which can be investigated from wild animals sold in the Wuhan Huanan Seafood Market, and can also investigate the transmission route of the new coronavirus, after all, the Wuhan Huanan Seafood Market has not reported the sale of bats.
Tracing the source and intermediate host of the nCoV-2019 virus is conducive to blocking the virus transmission chain, which is a long-term work, and tracing the source after the epidemic is not easy, which requires a lot of work and sustained monitoring. The current speculation about the origin of the nCoV-2019 virus is based on preliminary research results and there is not enough experimental evidence, so it has caused a lot of controversy. Therefore, confirming the source and intermediate host of nCoV-2019 virus will be the focus of research work for a long time to come, which requires the concerted efforts of many domestic scientific research teams to screen the carrying and transmission of nCoV-2019 virus in wild animals.
Not only that, in the long run, our country needs to establish a spectrum of wild animals carrying viruses, continuously monitor the spread and mutation of the virus, and make a good warning of diseases at the national and even global levels to deal with outbreaks such as this epidemic. In addition, the legislation and law enforcement of the illegal trade and consumption of wild animals cannot be ignored.
Finally, the top priority now should be to prevent and control the epidemic and help the people of Wuhan and the whole country tide over the difficulties.
Source: Kunming Institute of Zoology, Chinese Academy of Sciences