For the ongoing outbreak of coronavirus disease 2019, colloquially called “coronavirus”, see 2019–20 coronavirus outbreak. For the virus strain causing said outbreak, see Severe acute respiratory syndrome coronavirus 2.
Orthocoronavirinae
Coronaviruses 004 lores.jpg
Electron micrograph of avian infectious bronchitis virus
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Illustration of the morphology of coronaviruses; the club-shaped viral spike peplomers, coloured red, create the look of a corona surrounding the virion, when viewed electron microscopically
Virus classificatione
(unranked): Virus
Realm: Riboviria
Phylum: incertae sedis
Order: Nidovirales
Family: Coronaviridae
Subfamily: Orthocoronavirinae
Genera[1]
Alphacoronavirus
Betacoronavirus
Gammacoronavirus
Deltacoronavirus
Synonyms[2][3][4]
Coronavirinae
Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that are typically mild, such as some cases of the common cold (among other possible causes, predominantly rhinoviruses), though rarer forms can be lethal, such as SARS, MERS, and COVID-19. Symptoms vary in other species: 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.

Coronaviruses constitute the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales, and realm Riboviria.[5][6] 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 27 to 34 kilobases, the largest among known RNA viruses.[7] The name coronavirus is derived from the Latin corona, meaning “crown” or “halo”, which refers to the characteristic appearance reminiscent of a crown or a solar corona around the virions (virus particles) when viewed under two-dimensional transmission electron microscopy, due to the surface covering in club-shaped protein spikes.