page_title: Coronavirus
section_title: Classification
hierarchical_section_title: Coronavirus / Classification
caption_attribution_description: English: Phylogenetic analysis of RNA-dependent RNA polymerases (Pol) of coronaviruses with complete genome sequences available. The tree was constructed by the neighbor-joining method and rooted using Breda virus polyprotein. Bootstrap values were calculated from 1000 trees. 1118 amino acid positions in Pol were included. The scale bar indicates the estimated number of substitutions per 20 amino acids. All abbreviations for the coronaviruses were the same as those in Figure 1.
context_page_description: Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the common cold, while more lethal varieties can cause SARS, MERS, and COVID-19. In cows and pigs they cause diarrhea, while in mice they cause hepatitis and encephalomyelitis. There are as yet no vaccines or antiviral drugs to prevent or treat human coronavirus infections.
  Coronaviruses constitute the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales, and realm Riboviria. They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 26 to 32 kilobases, one of the largest among RNA viruses. They have characteristic club-shaped spikes that project from their surface, which in electron micrographs create an image reminiscent of the solar corona, from which their name derives.
context_section_description: The scientific name for coronavirus is Orthocoronavirinae or Coronavirinae. Coronaviruses belong to the family of Coronaviridae, order Nidovirales, and realm Riboviria. They are divided into alphacoronaviruses and betacoronaviruses which infect mammals – and gammacoronaviruses and deltacoronaviruses, which primarily infect birds.
  Genus: Alphacoronavirus; type species: Alphacoronavirus 1 (TGEV)
  Species: Alphacoronavirus 1, Human coronavirus 229E, Human coronavirus NL63, Miniopterus bat coronavirus 1, Miniopterus bat coronavirus HKU8, Porcine epidemic diarrhea virus, Rhinolophus bat coronavirus HKU2, Scotophilus bat coronavirus 512
  Genus Betacoronavirus; type species: Murine coronavirus (MHV)
  Species: Betacoronavirus 1 (Bovine Coronavirus, Human coronavirus OC43), Hedgehog coronavirus 1, Human coronavirus HKU1, Middle East respiratory syndrome-related coronavirus, Murine coronavirus, Pipistrellus bat coronavirus HKU5, Rousettus bat coronavirus HKU9, Severe acute respiratory syndrome-related coronavirus (SARS-CoV, SARS-CoV-2), Tylonycteris bat coronavirus HKU4
  Genus Gammacoronavirus; type species: Avian coronavirus (IBV)
  Species: Avian coronavirus, Beluga whale coronavirus SW1
  Genus Deltacoronavirus; type species: Bulbul coronavirus HKU11
  Species: Bulbul coronavirus HKU11, Porcine coronavirus HKU15
caption: Phylogenetic tree of coronaviruses
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