|Severe acute respiratory syndrome coronavirus 2|
|Electron micrograph of SARS-CoV-2 virions with visible coronae|
|Illustration of a SARS-CoV-2 virion|
Severe acute respiratory syndrome coronavirus 2
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2),previously known by the provisional name 2019 novel coronavirus (2019-nCoV), is a positive-sense single-stranded RNA virus. It is contagious in humans and is the cause of the ongoing pandemic of coronavirus disease 2019 (COVID-19) that has been designated a Public Health Emergency of International Concern by the World Health Organization (WHO).
SARS-CoV-2 has close genetic similarity to bat coronaviruses, suggesting it emerged from a bat-borne virus.An intermediate animal reservoir such as a pangolin is also thought to be involved in its introduction to humans. From a taxonomic perspective, SARS-CoV-2 is classified as a strain of the species Severe acute respiratory syndrome-related coronavirus (SARSr-CoV).
The strain was first discovered in Wuhan, China, so it is sometimes referred to as the "Wuhan virus"or "Wuhan coronavirus". Because the World Health Organization discourages the use of names based upon locations and to avoid confusion with the disease SARS, it sometimes refers to the virus as "the virus responsible for COVID-19" or "the COVID-19 virus" in public health communications. The general public often call both the virus and the disease "coronavirus", but scientists typically use more precise terms.
Human-to-human transmission of SARS-CoV-2 has been confirmed during the 2019–20 coronavirus pandemic. 2 metres (6.6 ft). Indirect contact via contaminated surfaces is another possible cause of infection. Preliminary research indicates that the virus may remain viable on plastic and steel for up to three days, but does not survive on cardboard for more than one day or on copper for more than four hours; the virus is inactivated by soap, which destabilizes its lipid bilayer. Viral RNA has also been found in stool samples from infected people.Transmission occurs primarily via respiratory droplets from coughs and sneezes within a range of about
Whether the virus is infectious during the incubation period is uncertain.On 1 February 2020, the World Health Organization (WHO) indicated that "transmission from asymptomatic cases is likely not a major driver of transmission". However, an epidemiological model of the beginning of the outbreak in China suggested that "pre-symptomatic shedding may be typical among documented infections" and that subclinical infections may have been the source of a majority of infections.
The first known infections from the SARS-CoV-2 strain were discovered in Wuhan, China.The original source of viral transmission to humans and when the strain became pathogenic remains unclear. Because many of the first individuals found to be infected by the virus were workers at the Huanan Seafood Market, it has been suggested that the strain might have originated from the market. However, other research indicates that visitors may have introduced the virus to the market, which then facilitated rapid expansion of the infections.
Research into the natural reservoir of the virus strain that caused the 2002–2004 SARS outbreak has resulted in the discovery of many SARS-like bat coronaviruses, most originating in the Rhinolophus genus of horseshoe bats, and two viral nucleic acid sequences found in samples taken from Rhinolophus sinicus show a resemblance of 80% to SARS-CoV-2.A third viral nucleic acid sequence from Rhinolophus affinis , collected in Yunnan province and designated RaTG13, has a 96% resemblance to SARS-CoV-2. The WHO considers bats the most likely natural reservoir of SARS-CoV-2, but differences between the bat coronavirus and SARS-CoV-2 suggest that humans were infected via an intermediate host.
A metagenomic study published in 2019 previously revealed that SARS-CoV, the strain of the virus that causes SARS, was the most widely distributed coronavirus among a sample of Sunda pangolins.On 7 February 2020, it was announced that researchers from Guangzhou had discovered a pangolin sample with a viral nucleic acid sequence "99% identical" to SARS-CoV-2. When released, the results clarified that "the receptor-binding domain of the S protein of the newly discovered Pangolin-CoV is virtually identical to that of 2019-nCoV, with one amino acid difference." Pangolins are protected under Chinese law, but their poaching and trading for use in traditional Chinese medicine remains common.
Microbiologists and geneticists in Texas have independently found evidence of reassortment in coronaviruses suggesting involvement of pangolins in the origin of SARS-CoV-2.However, pangolin coronaviruses found to date only share at most 92% of their whole genomes with SARS-CoV-2, making them less similar than RaTG13 to SARS-CoV-2. This is insufficient to prove pangolins to be the intermediate host; in comparison, the SARS virus responsible for the 2002–2004 outbreak shared 99.8% of its genome with a known civet coronavirus.
Genomic organisation of isolate Wuhan-Hu-1, the earliest sequenced sample of SARS-CoV-2
|NCBI genome ID|
|Genome size||29,903 bases|
|Year of completion||2020|
SARS-CoV-2 belongs to the broad family of viruses known as coronaviruses. It is a positive-sense single-stranded RNA (+ssRNA) virus. Other coronaviruses are capable of causing illnesses ranging from the common cold to more severe diseases such as Middle East respiratory syndrome (MERS). It is the seventh known coronavirus to infect people, after 229E, NL63, OC43, HKU1, MERS-CoV, and the original SARS-CoV.
Like the SARS-related coronavirus strain implicated in the 2003 SARS outbreak, SARS-CoV-2 is a member of the subgenus Sarbecovirus (beta-CoV lineage B).Its RNA sequence is approximately 30,000 bases in length. SARS-CoV-2 is unique among known betacoronaviruses in its incorporation of a polybasic cleavage site, a characteristic known to increase pathogenicity and transmissibility in other viruses.
With a sufficient number of sequenced genomes, it is possible to reconstruct a phylogenetic tree of the mutation history of a family of viruses. By 12 January 2020, five genomes of SARS-CoV-2 had been isolated from Wuhan and reported by the Chinese Center for Disease Control and Prevention (CCDC) and other institutions; As of 13 March 2020, [update] 410 SARS-CoV-2 genomes sampled on five continents were publicly available.the number of genomes increased to 42 by 30 January 2020. A phylogenetic analysis of those samples showed they were "highly related with at most seven mutations relative to a common ancestor", implying that the first human infection occurred in November or December 2019.
On 11 February 2020, the International Committee on Taxonomy of Viruses (ICTV) announced that according to existing rules that compute hierarchical relationships among coronaviruses on the basis of five conserved sequences of nucleic acids, the differences between what was then called 2019-nCoV and the virus strain from the 2003 SARS outbreak were insufficient to make them separate viral species. Therefore, they identified 2019-nCoV as a strain of severe acute respiratory syndrome-related coronavirus .
Each SARS-CoV-2 virion is approximately 50–200 nanometres in diameter.Like other coronaviruses, SARS-CoV-2 has four structural proteins, known as the S (spike), E (envelope), M (membrane), and N (nucleocapsid) proteins; the N protein holds the RNA genome, and the S, E, and M proteins together create the viral envelope. The spike protein, which has been imaged at the atomic level using cryogenic electron microscopy, is the protein responsible for allowing the virus to attach to the membrane of a host cell.
Protein modeling experiments on the spike protein of the virus soon suggested that SARS-CoV-2 has sufficient affinity to the angiotensin converting enzyme 2 (ACE2) receptors of human cells to use them as a mechanism of cell entry.By 22 January 2020, a group in China working with the full virus genome and a group in the United States using reverse genetics methods independently and experimentally demonstrated that ACE2 could act as the receptor for SARS-CoV-2. Studies have shown that SARS-CoV-2 has a higher affinity to human ACE2 than the original SARS virus strain. SARS-CoV-2 may also use basigin to gain cell entry.
Initial spike protein priming by transmembrane protease, serine 2 (TMPRSS2) is essential for entry of SARS-CoV-2. [ better source needed ] SARS-CoV-2 produces at least three virulence factors that promote shedding of new virions from host cells and inhibit immune response.After a SARS-CoV-2 virion attaches to a target cell, the cell's protease TMPRSS2 cuts open the spike protein of the virus, exposing a fusion peptide. The virion then releases RNA into the cell, forcing the cell to produce copies of the virus that are disseminated to infect more cells.
Based upon the low variability exhibited among known SARS-CoV-2 genomic sequences, the strain is thought to have been detected by health authorities within weeks of its emergence among the human population in late 2019.The earliest case of infection currently known is thought to have been found on 17 November 2019. The virus subsequently spread to all provinces of China and to more than one hundred other countries in Asia, Europe, North America, South America, Africa, and Oceania. Human-to-human transmission of the virus has been confirmed in all of these regions. On 30 January 2020, SARS-CoV-2 was designated a Public Health Emergency of International Concern by the WHO, and on 11 March 2020 the WHO declared it a pandemic.
As of 30 March 2020 (04:00 UTC), there were 723,328 confirmed cases of infection, of which approximately 81,400 were in mainland China. While the proportion of infections that result in confirmed infection or progress to diagnosable disease remains unclear, one mathematical model estimated the number of people infected in Wuhan alone at 75,815 as of 25 January 2020, at a time when confirmed infections were far lower. The total number of deaths attributed to the virus was 34,005 as of 30 March 2020 (04:00 UTC); 151,991 people had recovered from infection by that time. Less than a tenth of all deaths have occurred in Hubei province, where Wuhan is located. Before 24 February 2020, the proportion was over 95%.
The basic reproduction number () of the virus has been estimated to be between 1.4 and 3.9. This means that each infection from the virus is expected to result in 1.4 to 3.9 new infections when no members of the community are immune and no preventive measures are taken. The reproduction number may be higher in densely populated conditions such as those found on cruise ships.
Coronaviruses are a group of related viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that can be mild, such as some cases of the common cold, and others that can be lethal, such as SARS, MERS, and COVID-19. Symptoms in other species vary: in chickens, they cause an upper respiratory tract disease, while in cows and pigs they cause diarrhea. There are yet to be vaccines or antiviral drugs to prevent or treat human coronavirus infections.
Severe acute respiratory syndrome-related coronavirus (SARSr-CoV) is a species of coronavirus that infects humans, bats and certain other mammals. It is an enveloped positive-sense single-stranded RNA virus that enters its host cell by binding to the ACE2 receptor. It is a member of the genus Betacoronavirus and subgenus Sarbecoronavirus.
Coronaviridae is a family of enveloped, positive-sense, single-stranded RNA viruses. The viral genome is 26–32 kilobases in length. The particles are typically decorated with large (~20 nm), club- or petal-shaped surface projections, which in electron micrographs of spherical particles create an image reminiscent of the solar corona.
Angiotensin converting enzyme 2 (ACE2) is an enzyme attached to the outer surface of cells in the lungs, arteries, heart, kidney, and intestines. ACE2 lowers blood pressure by catalysing the cleavage of angiotensin II into angiotensin 1–7. ACE2 also serves as the entry point into cells for some coronaviruses.
Severe acute respiratory syndrome coronavirus (SARS-CoV) is the strain of virus that causes severe acute respiratory syndrome (SARS). It is an enveloped, positive-sense, single-stranded RNA virus which infects the epithelial cells within the lungs. The virus enters the host cell by binding to the ACE2 receptor. It infects humans, bats, and palm civets.
Middle East respiratory syndrome (MERS), also known as camel flu, is a viral respiratory infection caused by the MERS-coronavirus (MERS-CoV). Symptoms may range from mild to severe. They include fever, cough, diarrhea and shortness of breath. Disease is typically more severe in those with other health problems. Mortality is about one-third of diagnosed cases.
Betacoronaviruses are one of four genera of coronaviruses of the subfamily Orthocoronavirinae in the family Coronaviridae, of the order Nidovirales. They are enveloped, positive-sense, single-stranded RNA viruses of zoonotic origin. The coronavirus genera are each composed of varying viral lineages with the betacoronavirus genus containing four such lineages. In older literature, this genus is also known as group 2 coronaviruses.
A bat-borne virus is any virus whose primary reservoir is any species of bat. The viruses include coronaviruses such as severe acute respiratory syndrome coronavirus (SARS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); hantaviruses; lyssaviruses such as rabies virus and Australian bat lyssavirus; henipaviruses such as nipah virus and Hendra virus; Lassa virus; Ebola virus; and Marburg virus. Several bat-borne viruses are considered important emerging viruses.
Remdesivir is a novel antiviral drug in the class of nucleotide analogs. It was developed by Gilead Sciences as a treatment for Ebola virus disease and Marburg virus infections, though it subsequently was found to show antiviral activity against other single stranded RNA viruses such as respiratory syncytial virus, Junin virus, Lassa fever virus, Nipah virus, Hendra virus, and the coronaviruses. It is being studied for SARS-CoV-2 and Henipavirus infections. Based on success against other coronavirus infections, Gilead provided remdesivir to physicians who treated an American patient in Snohomish County, Washington in 2020, who was infected with SARS-CoV-2, and is providing the compound to China to conduct a pair of trials in infected individuals with and without severe symptoms.
Shi Zhengli is a Chinese virologist and writer. She is a researcher at the Wuhan Institute of Virology (WIV), which is part of the Chinese Academy of Sciences (CAS). Shi and her colleague Cui Jie found that the SARS virus originated in bats. Shi is a member of the Virology Committee of the Chinese Society for Microbiology. She is an editor of the Board of Virologica Sinica, the Chinese Journal of Virology, and the Journal of Fishery Sciences of China.
The 2019–20 coronavirus pandemic is an ongoing pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak was first identified in Wuhan, Hubei, China, in December 2019. The World Health Organization (WHO) declared the outbreak to be a Public Health Emergency of International Concern on 30 January 2020 and recognized it as a pandemic on 11 March. As of 30 March 2020, more than 723,000 cases of COVID-19 have been reported in over 190 countries and territories, resulting in approximately 34,000 deaths. More than 151,500 people have since recovered.
The Huanan Seafood Wholesale Market, also known as the Huanan Seafood Market, was a live animal and seafood market in Jianghan District, Wuhan, Hubei, China. The market gained media attention after being identified as a point of origin of the 2019–20 coronavirus pandemic. The World Health Organization was notified on 31 December 2019 about an outbreak of pneumonia in Wuhan. Of the initial 41 people hospitalized with pneumonia who were officially identified as having laboratory-confirmed SARS-CoV-2 infection by 2 January 2020, two-thirds were exposed to the market. The market was closed on 1 January 2020 for sanitary procedures and disinfection. 33 out of 585 environmental samples obtained from the market indicated evidence of coronavirus disease 2019 (COVID-19).
This article documents the chronology and epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the 2019–20 coronavirus pandemic originating in Wuhan, China. Some developments may become known or fully understood only in retrospect.
The Wuhan Institute of Virology is a research institute on virology administered by the Chinese Academy of Sciences (CAS). Located in Jiangxia District, Wuhan, Hubei, it opened mainland China's first biosafety level 4 (BSL–4) laboratory in 2015.
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease was first identified in 2019 in Wuhan, the capital of China's Hubei province, and has since spread globally, resulting in the ongoing 2019–20 coronavirus pandemic. Common symptoms include fever, cough, and shortness of breath. Other symptoms may include muscle pain, sputum production, diarrhea, sore throat, loss of smell, and abdominal pain. While the majority of cases result in mild symptoms, some progress to pneumonia and multi-organ failure. As of March 28, 2020, the overall rate of deaths per number of diagnosed cases is 4.6 percent; ranging from 0.2 percent to 15 percent according to age group and other health problems.
Laboratory testing for the respiratory coronavirus disease 2019 (COVID-19) and the associated SARS-CoV-2 virus includes methods that detect the presence of virus and those that detect antibodies produced in response to infection. Detection of antibodies (serology) can be used both for clinical purposes and population surveillance.
A COVID-19 vaccine is a hypothetical vaccine against coronavirus disease 2019 (COVID-19). Although no vaccine has completed clinical trials, there are multiple attempts in progress to develop such a vaccine. In late February 2020, the World Health Organization (WHO) said it did not expect a vaccine against SARS-CoV-2, the causative virus, to become available in less than 18 months. By late March 2020, some 40 vaccine candidates were in development.
Drug repositioning – the investigation of existing drugs for new therapeutic purposes – is one line of scientific research which is followed to develop safe and effective COVID-19 treatments. Other research directions include the development of a COVID-19 vaccine.
COVID-19 drug development is the research process to develop a preventative vaccine or therapeutic prescription drug that would alleviate the severity of 2019-20 coronavirus disease (COVID-19). Internationally as of March 2020, some 100 drug companies, biotechnology firms, university research groups, and health organizations were involved in stages of vaccine or drug development. The World Health Organization (WHO), European Medicines Agency (EMA), US Food and Drug Administration (FDA), and the Chinese government and drug manufacturers were coordinating with academic and industry researchers to speed development of vaccines, antiviral drugs, and monoclonal antibody therapies.
From a risk communications perspective, using the name SARS can have unintended consequences in terms of creating unnecessary fear for some populations.... For that reason and others, WHO has begun referring to the virus as "the virus responsible for COVID-19" or "the COVID-19 virus" when communicating with the public. Neither of these designations are [sic] intended as replacements for the official name of the virus as agreed by the ICTV.
|Wikimedia Commons has media related to SARS-CoV-2 .|
|Wikispecies has information related to Severe acute respiratory syndrome coronavirus 2|
|Wikiquote has quotations related to: SARS-CoV-2|
|Scholia has a profile for SARS-CoV-2 (Q82069695) .|