What is coronavirus?
Coronaviruses and toroviruses are two virus genera within the virus family Coronaviridae, order Nidovirales. Coronaviruses are well-established pathogens of humans and animals while the toroviruses are recognized as causes of animal diarrhoea. Toroviruses have also been found in human faeces but their aetiological role remains unclear.
Coronaviruses are classified into three groups, initially based on antigenic relationships of the spike (S), membrane (M) and nucleocapsid (N) proteins and now re-enforced by viral genetic phylogeny. The HCoVs 229E and NL63 are group 1 coronaviruses, while OC43, HKU-1 and SARS coronaviruses are classified in group 2. Group 3 coronaviruses are found in avian species. Genetic recombination readily occurs between members of the same and of different coronavirus groups providing opportunity for increased genetic diversity.
Efforts to identify the animal reservoir of SARS coronavirus led to the discovery of diverse bat coronaviruses in both group 1 and 2 that are closely related phylogenetically to different mammalian coronaviruses. It has been proposed that bat coronaviruses may indeed have been the ancestors of many mammalian coronaviruses.
Coronaviruses are a family of viruses known for containing strains that cause potentially deadly diseases in mammals and birds. In humans they're typically spread via airborne droplets of fluid produced by infected individuals.
Some rare but notable strains, including SARS-CoV-2 (responsible for COVID-19), and those responsible for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) can cause death in humans.
CoronaVirus in Human?
Coronavirus disease was first described in 1931, with the first coronavirus (HCoV-229E) isolated from humans in 1965. Until the outbreak of severe acute respiratory syndrome in late 2002, only two human coronaviruses (HCoV) were known – HCoV-229E and HCoV-OC43. Once the SARS coronavirus (SARS-CoV) had been identified, two further human coronaviruses were identified. Three groups of coronaviruses exist: group 1 (HCoV-229E and HCoV-NL63), group 2 (HCoVOC43 and HCoV-HKU1), group 3 (no human CoVs as yet). SARS-CoV is an outlier to all three groups, although some place it in group 2.
COVID-19 (Novel coronavirus-19) is a new strain of coronavirus (a large family of viruses) that had previously not been identified in humans. It first emerged in Wuhan, China, in December 2019, and has since been declared as an outbreak by World Health Organization (WHO). In very rare cases, the disease could be fatal. Older people or patients who already have diseases such as diabetes or heart problems may be vulnerable to becoming severely ill because of this virus.
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