Wuhan is a new type of coronavirus, so what is the coronavirus? How many classes does it fall into? What are the manifestations of human infection with coronavirus? Let's hear from the CDC.
The coronavirus belongs to the cluster virus order, the coronavirus family, the coronavirus family, is one kind has the capsule? Genomic RNA virus with linear single strand positive chain is a large class of viruses in nature. the viral genome 5' end has a methylated cap-like structure, and the 3' end has a poly (a) tail. the genome is about 27–32 kb in length. it is the largest known rna virus in the genome.
According to the phylogenetic tree, the coronavirus can be divided into four genera:α,\946;,\947;,δ, among which \946; belongs to the coronavirus can be divided into four independent subgroups A, B, C and D groups.
So far, in addition to the new coronavirus that caused the outbreak of viral pneumonia in Wuhan, a total of six human coronaviruses (HCV-229E, HCV-OC43, SARS-CoV, HCV-NL63, HCV-HKU1 and MERS-CoV) have been found.
HCV-229E and HCV-NL63 belong to α coronavirus, HCV-OC43, SARS-CoV, HCV-HKU1 and MERS-CoV all belong to beta coronavirus. Among them, HCV-OC43 and HCV-HKU1 belong to A subgroup, SARS-CoV belongs to B subgroup, and MERS-CoV belongs to C subgroup (see below).
The human coronavirus is more sensitive to heat, the virus is moderately stable in the appropriate solution at 4°C, and can be preserved at -60°C for several years, but with the increase of temperature, the resistance of the virus decreases, such as HCoV-229E at 56°C for 10 minutes or 37°C for several hours, SARS-CoV can survive at 37°C for 4 days, heat at 56°C for 90 minutes and heat at 75°C for 30 minutes.
human coronaviruses are sensitive to organic solvents and disinfectants.75% alcohol, ether, chloroform, formaldehyde, chlorine-containing disinfectants, peracetic acid, and ultraviolet rays can inactivate the virus.
The human coronavirus SARS-CoV can survive in urine for at least 10 days at room temperature of 24°C, in sputum and feces of diarrhea patients for more than 5 days, in blood for about 15 days, and in plastic, glass, mosaic, metal, cloth, photocopying paper and other objects for 2-3 days.
Globally,10% to 30% of upper respiratory tract infections are caused by HCV-229E, HCV-OC43, HCV-NL63, and HCV-HKU1, the second most common cause of the common cold, second only to rhinovirus. Infection is seasonally prevalent, with high incidence in spring and winter every year. incubation period of 2-5 days, the population is generally susceptible. spread mainly through human contact.
SARS, caused by human infection with SARS-CoV, first appeared in parts of Guangdong province of China, and then spread to 24 provinces, autonomous regions, municipalities directly under the Central Government and 28 other countries and regions around the world. From November 2002 to July 2003, a total of 8096 cases of clinical diagnosis,774 deaths and% mortality were reported. The incubation period for SARS is usually limited to 2 weeks, usually about 2 to 10 days. The population is generally susceptible. SARS patients are the main source of infection, the patients with obvious symptoms are more infectious, incubation period or cure patients are not infectious. No human cases of SARS have been reported globally since 2004.
MERS, a viral respiratory disease caused by MERS-CoV, was first identified in Saudi Arabia in 2012. Since 2012, MERS has affected 27 countries and regions, including the Middle East, Asia and Europe, and so far has reported 2,468 cases,851 deaths and about% mortality. 80 per cent of cases are from Saudi Arabia. One case of imported MERS occurred in our country. The incubation period of the disease was 2-14 days, and the population was generally susceptible. Single-peak camel is the main storage host of MERS-CoV, and is the main source of infection in human cases, with limited human-to-human transmission capacity, and it is found that only in medical institutions, if there is no effective protection in close contact with patients, there may be interpersonal transmission phenomenon.
Common human-infected coronaviruses (including type 229E, NL63, OC43, and HKU1) typically cause mild or moderate upper respiratory diseases such as colds. The symptoms are mild, mainly including runny nose, headache, cough, sore throat, fever and so on. Sometimes it causes lower respiratory diseases, such as pneumonia or bronchitis, which are more common in patients with cardiopulmonary diseases, people with low immunity, infants and the elderly.
MERS-CoV and SARS-CoV can often cause severe symptoms. MERS symptoms typically include fever, cough and shortness of breath, and even develop pneumonia, with a fatality rate of about%. SARS symptoms typically include fever, chills and body pain, and even develop pneumonia, with a fatality rate of about%.
Among the six known coronaviruses that can infect humans, the severity and social impact of coronaviruses in the Middle East respiratory syndrome coronaviruses (MERS-CoV) and severe acute respiratory syndrome coronaviruses (SARS-CoV) are far more sophisticated than other coronaviruses.
Pathogenic detection mainly includes virus isolation, virus nucleic acid detection. virus isolation as a “gold standard ” for laboratory testing. virus nucleic acid detection can be used for early diagnosis. A variety of specimens (pharyngeal swabs, nasal swabs, nasopharyngeal or tracheal extracts, sputum or lung tissue, and blood and feces) should be retained in time for detection, among which the positive detection rate of the following respiratory specimens is higher.