Human coronavirus OC43


Human coronavirus OC43 is a member of the species Betacoronavirus 1, which infects humans and cattle. The infecting coronavirus is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid receptor.
OC43 is one of seven known coronaviruses to infect humans. It is one of the viruses responsible for the common cold. It has, like other coronaviruses from genus Betacoronavirus, subgenus Embecovirus, an additional shorter spike protein called hemagglutinin esterase.

Virology

Four HCoV-OC43 genotypes, have been identified with genotype D most likely arising from genetic recombination. The complete genome sequencing of two genotype C and D strains and bootscan analysis shows recombination events between genotypes B and C in the generation of genotype D. Of 29 strains identified, none belong to the more ancient genotype A. Molecular clock analysis using spike and nucleocapsid genes dates the most recent common ancestor of all genotypes to the 1950s. Genotype B and C date to the 1980s. Genotype B to the 1990s, and genotype C to the late 1990s to early 2000s. The recombinant genotype D strains were detected as early as 2004.
Comparison of HCoV-OC43 with the most closely related strain of Betacoronavirus 1 species, bovine coronavirus, indicated that they had a most recent common ancestor in the late 19th century, with several methods yielding most probable dates around 1890, leading authors to speculate that an introduction of the former strain to the human population might have caused the 1889–1890 flu pandemic. HCoV-OC43 likely originated in rodents.
HCoV-OC43 is one of seven known coronaviruses to infect humans. The other six are:
Along with HCoV-229E, a species in the genus Alphacoronavirus, HCoV-OC43 are among the known viruses that cause the common cold. Both viruses can cause severe lower respiratory tract infections, including pneumonia in infants, the elderly, and immunocompromised individuals such as those undergoing chemotherapy and those with HIV/AIDS.

Epidemiology

Coronaviruses have a worldwide distribution, causing 10–15% of common cold cases. Infections show a seasonal pattern with most cases occurring in the winter months.