Human coronavirus OC43

Human coronavirus OC43^[1] (HCoV-OC43) is a member of the species Betacoronavirus gravedinis,^[2] which infects humans and cattle.^[3][4] The infecting coronavirus is an enveloped, positive-sense, single-stranded RNA virus that enters its host cell by binding to the N-acetyl-9-O-acetylneuraminic acid receptor.^[5] OC43 is one of seven coronaviruses known to infect humans. It is one of the viruses responsible for the common cold^[6][7] and may have been responsible for the 1889–1890 pandemic.^[8] It has, like other coronaviruses from genus Betacoronavirus, subgenus Embecovirus, an additional shorter spike protein called hemagglutinin-esterase (HE).^[9][3] ]. Genetic and antigenic analyses reveal significant similarities between HCoV-OC43 and bovine coronavirus (BCoV), suggesting a zoonotic transmission event from cattle to humans.^[10] Molecular analysis estimate that this cross-species transmission occurred sometime in the late 19th century, possibly around 1890.^[10] This period aligns with the "Russian Influenza" pandemic that occurred form 1889 -1892. This has led some researchers to theorize that HCoV-OC43 may have been the causative agent of that pandemic, rather than the influenza virus.^[11] This theory is further supported by phylogenetic studies indicating a recent common ancestor between HCoV-OC43 and BCoV around that time.^[11]