[ Instrument Network Instrument R & D ] Wei Xiaoman and Li Xiang, members of the Cui Jie research group of the Shanghai Pasteur Institute of the Chinese Academy of Sciences and the Shanghai Branch of the Biosafety Science Center of the Chinese Academy of Sciences, based on the results of the new coronavirus (2019-nCoV) analysis and The results of genome comparison uploaded from the public database were comprehensively analyzed, and the early evolution mechanism of the new coronavirus was estimated to provide a scientific basis for the prevention and control of the pneumonia epidemic of new coronavirus infection.
2019-nCoV is different from any of the previously known six types of coronaviruses that can infect humans, including HCoV-229E, HCoV-OC43, SARS-CoV, HCoV-NL63, HCoV-HKU1, and MERS-CoV. Infects human coronavirus and can cause pneumonia. Genomics analysis of 2019-nCoV showed that it is significantly different from SARS and MERS viruses, with genomic differences of 21% and 50%, respectively. Although both belong to Beta coronavirus, 2019-nCoV is not the same as SARS and MERS coronavirus. It can be considered a distant relative of SARS coronavirus, and it is definitely not a variant of SARS coronavirus or a resurgence of SARS.
Coronaviruses are systematically classified as Coronaviridae (Coronaviridae). Coronavirus is a positive-stranded single-stranded RNA virus with an envelope of about 80 to 120 nm in diameter. Its genetic material is the largest of all RNA viruses and infects humans, mice, pigs, cats, dogs, wolves, Vertebrates of chicken, cattle and poultry. A variant of coronavirus is the pathogen that causes atypical pneumonia and belongs to the RNA virus. Coronavirus was isolated from chickens in 1937. The diameter of the virus particles is 60-200nm, and the average diameter is 100nm. It is spherical or oval and has polymorphism. The virus has an envelope, and there are spinous processes on the envelope. The entire virus looks like a corona, and the spinous processes of different coronaviruses are significantly different. Tubular inclusions are sometimes seen in coronavirus-infected cells.
Research suggests that under long-term coexistence of the coronavirus and the host, the virus usually spreads in the same species, such as bats, due to host restrictions, but in a few cases, different viruses recombine after infecting the same host cell, resulting in a series of Recombinants with different genetic material. Some of these newly recombined viruses have the ability to infect new hosts (other animals or humans). Judging from the available data, the new coronavirus showed weak infectivity in early evolution and can also be transmitted from person to person, but its ability to transmit cannot be ignored. Phylogenetic analysis showed that the virus lacked topology and clustering was not obvious. However, analysis of 2019-nCoV found that at least 17 sites on different proteins involved amino acid changes, and several of these mutations were more common in clustered cases of Guangdong families.
Coronavirus is one of the main pathogens of the common cold in adults. It can cause upper respiratory tract infections in children, and rarely affects the lower respiratory tract. The incubation period for coronavirus infection is usually 2 to 5 days, with an average of 3 days. Typical coronavirus infections have cold symptoms such as runny nose and discomfort. Different types of viruses have different pathogenicity and cause different clinical manifestations. The symptoms caused by OC43 strain are generally more severe than those of 229E virus. Coronavirus infection can cause fever, chills, and vomiting. The course of disease is usually about 1 week, the clinical course is mild, and there are no sequelae.
As for whether the virus has undergone adaptive evolution, it is not yet conclusive, and more viral genome analysis and subsequent functional experiment verification of mutation sites are needed. In the future, researchers will focus on analyzing the evolutionary pattern of viruses in nature and in the population, and clarify the origin of 2019-nCoV and the evolutionary mechanism of its interaction with intermediate hosts. Researchers also called for close monitoring of the mutations, evolution and spread of the virus, which is necessary to guide the control of the epidemic.
There is specific prevention for its prevention, that is, targeted preventive measures (the development of vaccines and vaccines is possible, but it takes a long time to solve the problem of virus reproduction is its problem) and non-specific preventive measures (that is, prevention of spring respiratory diseases) Measures such as keeping warm, washing hands, ventilating, avoiding excessive fatigue and contacting patients, and going to less public places, etc.).
Source: Encyclopedia, Chinese Academy of Sciences
