Alphacoronavirus

Alphacoronavirus is a genus of viruses in the family Coronaviridae, order Nidovirales. Members are enveloped, pleomorphic viruses with a positive-sense single-stranded RNA genome of roughly 27 to 32 kilobases. Like other coronaviruses, alphacoronaviruses display a characteristic spike (S) glycoprotein that forms a corona on the virion surface and mediates receptor binding and entry. The genome contains a large replicase gene (ORF1a/1b) encoding nonstructural proteins required for RNA synthesis, followed by structural protein genes for spike (S), envelope (E), membrane (M), and nucleocapsid (N); many species also express accessory proteins whose functions vary.

Hosts and transmission: Alphacoronaviruses infect a range of mammals, including humans, bats, pigs, cats, and dogs. Transmission routes are primarily respiratory and enteric, with cross-species spillover documented in some lineages. Disease ranges from mild upper respiratory illness to severe gastroenteritis in animals. In humans, alphacoronaviruses such as HCoV-229E and HCoV-NL63 typically cause common colds; pathogenicity varies by host factors and co-infections.

Notable members: HCoV-229E, HCoV-NL63; animal alphacoronaviruses include feline coronavirus (FCoV), canine coronavirus (CCoV), transmissible gastroenteritis virus (TGEV), and porcine epidemic diarrhea virus (PEDV).

Diagnosis and control: Detection relies on molecular methods such as RT-PCR. Management is typically supportive; vaccines exist for some animal alphacoronaviruses, while human vaccines are not broadly available. Taxonomically, alphacoronaviruses comprise one of the four genera of Coronaviridae.