On February 3, 2020 Beijing time, Nature, an international authoritative academic journal, published a research paper on the new coronavirus (2019-nCoV) by Shi Zhengli, a researcher at the Wuhan Virus Research Institute of the Chinese Academy of Sciences. The paper is titled: Bats are a possible source of a new type of coronavirus that is causing the pneumonia outbreak.
The paper is submitted on January 20, 2020, published on January 23, 2020 on the preprinted website BioRxiv, resuscitation on January 26, officially received on January 29 and published online on February 3.
Researcher Shi Zhengli’s team found evidence that the new coronavirus may have originated in bats, but the animal source of the outbreak has yet to be confirmed.
The paper notes that Shi Zhengli’s team found that the genome sequence of the new coronavirus is as similar as 96 percent at the whole genome level to a coronavirus in a bat, and speculated that the bat may be the source of the new coronavirus. This conclusion is consistent with the results published by the team on January 23rd in the paper preprinted on this website.
The characteristics of the new coronavirus (2019-nCoV) are described and studied. From 12 December 2019 to 26 January 2020, human acute respiratory syndrome (SARS) caused 2,050 confirmed infections and 56 deaths in the country, and 35 infections in 11 countries abroad. Typical clinical symptoms of these patients are fever, dry cough, dyspnea, headache and lung infections, which can be followed by injury to the respiratory alveoli, alveoli failure, and even death (lateral chest CT observation), which is determined to be viral pneumonia.
The team analyzed samples of seven virus patients admitted to hospital in late December 2019 (in the early stages of the outbreak), six of whom were workers at the Wuhan Seafood Market, which had first detected cases in December 2019. The researchers isolated the virus from a patient and used it to infect lab-grown cells. The study found that when the cell surface has ACE2 protein, the virus can invade the cell.
The virus can enter human cells through the ACE2 protein in the human body, or it may enter the cells through the ACE2 protein in Chinese chrysanthemum bats, fruit beavers, and pigs. This means that people, Chinese chrysanthemum bats, beavers and pigs can all carry the new coronavirus. Studies have also shown that mice cannot carry the new coronavirus.
The team obtained whole genome sequences from five patient samples, which were almost identical. The results showed that the new coronavirus has 79.5% genomic sequence similarity with SARS coronavirus, and the new coronavirus has 96% similarity to the coronavirus in bats at the whole genome level. The team confirmed that the new coronavirus enters the cell in the same path as the SARS coronavirus, which is through ACE2 cell receptors.
The authors note that the virus is most likely to spread through the human respiratory tract, while other routes of transmission require more patient data to confirm it. In the article, the authors also stress that the link between the new coronavirus and the outbreak has not been experimentally proven in animals, and therefore does not fully comply with the Koch Rule. The team also does not know how the virus travels between hosts.
The Koch Law was a scientifically validated method proposed by German bacteriologist Robert Koch (1843-1910) in 1884 to verify the relationship between bacteria and disease, which was later hailed as the golden rule of infectious disease pathogen identification.
Koch’s law includes:
The same microorganisms appear in each case and do not exist in healthy people;
To isolate such microorganisms from the host and obtain pure culture (pure culture) in the medium;
Inoculating a healthy and sensitive host with pure cultures of this microorganism, the same disease will recur;
The microbe can be re-isolated and cultured from the host of the experimental disease.
If the study completes the above four steps and has reached a definitive conclusion, it can be identified as the pathogen of the disease. But in koch’s days, there were many diseases that failed to meet the rules. With the development of medicine, many diseases have been confirmed to be caused by a pathogen, but not satisfied with the Koch rule.
Therefore, although the Koch law has a place in medicine, it can continue to help in microbial diagnosis, but with the rapid progress of modern medicine and the change of medical model, Koch’s law in clinical diagnostics face new revision and development.
Responding to The Work’s team’s findings, Ian Jones, professor of virology at the University of Reading in the UK, said: “This paper provides solid evidence of what is already well known. Both the new coronavirus and the SARS-causing coronavirus are viruses in bats, which caused a plague in 2003. In essence, the new coronavirus is more likely to spread than the coronavirus that causes SARS, but the death rate is smaller. The virus also uses the same receptor, which explains the spread of the virus and its cause of pneumonia. “
Ian Jones said the paper’s conclusions were very encouraging because “it shows that treatments, drugs and vaccines developed against SARS should be effective against new coronaviruses.” “