SARS-related coronavirus
Betacoronavirus pandemicum[2] (also known as Severe acute respiratory syndrome–related coronavirus, abbreviated as SARSr-CoV or SARS-CoV)[note 1] is a species of virus consisting of many known strains. Two strains of the virus have caused outbreaks of severe respiratory diseases in humans: severe acute respiratory syndrome coronavirus 1 (SARS-CoV or SARS-CoV-1), the cause of the 2002–2004 outbreak of severe acute respiratory syndrome (SARS), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the pandemic of COVID-19.[3][4] There are hundreds of other strains of SARSr-CoV, which are only known to infect non-human mammal species: bats are a major reservoir of many strains of SARSr-CoV; several strains have been identified in Himalayan palm civets, which were likely ancestors of SARS-CoV-1.[3][5][6][7]
This article is about a species of coronavirus comprising multiple strains. For the strain that causes SARS, see SARS-CoV-1. For the strain that causes COVID-19, see SARS-CoV-2.
These enveloped, positive-sense single-stranded RNA viruses enter host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor.[8] The SARSr-CoV species is a member of the genus Betacoronavirus and the only species of the subgenus Sarbecovirus (SARS Betacoronavirus).[9][10]
The SARS-related coronavirus was one of several viruses identified by the World Health Organization (WHO) in 2016 as a likely cause of a future epidemic in a new plan developed after the Ebola epidemic for urgent research and development before and during an epidemic towards diagnostic tests, vaccines and medicines. This prediction came to pass with the COVID-19 pandemic.[11][12]
Classification[edit]
SARS-related coronavirus is a member of the genus Betacoronavirus (group 2) and monotypic of the subgenus Sarbecovirus (subgroup B).[13] Sarbecoviruses, unlike embecoviruses or alphacoronaviruses, have only one papain-like proteinase (PLpro) instead of two in the open reading frame ORF1ab.[14] SARSr-CoV was determined to be an early split-off from the betacoronaviruses based on a set of conserved domains that it shares with the group.[15][16]
Bats serve as the main host reservoir species for the SARS-related coronaviruses like SARS-CoV-1 and SARS-CoV-2. The virus has coevolved in the bat host reservoir over a long period of time.[17] Only recently have strains of SARS-related coronavirus been observed to have evolved into having been able to make the cross-species jump from bats to humans, as in the case of the strains SARS-CoV-1 and SARS-CoV-2.[18][8] Both of these strains descended from a single ancestor but made the cross-species jump into humans separately. SARS-CoV-2 is not a direct descendant of SARS-CoV-1.[3]
