Coronavirus Primer
Background
The first human coronavirus (HCoV), strain B814, was isolated in 1965 from the nasal discharge of a patient with a common cold. Since then, more than 30 additional strains were identified. Among them, the prototypic stain HCoV-229E (named after a student specimen coded 229E) was isolated using standard tissue culture. HCoV-OC43 (Organ Culture 43) was later recovered using tracheal organ culture and found to be serologically distinct from HCoV-229E. These two viruses were the focus of HCoV research in the following years, until the emergence of the highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002–2003. In the post SARS era, two more HCoVs were identified. HCoV-NL63 (NetherLand 63) was isolated from the aspirate of a 7-month-old infant with bronchiolitis in 2004, whereas HCoV-HKU1 (Hong Kong University 1) was isolated from a Hong Kong patient with pneumonia in 2005. Since then, two more zoonotic HCoVs have emerged, namely as the Middle East respiratory syndrome coronavirus (MERS-CoV) and the 2019 novel coronavirus (2019-nCoV, a.k.a. SARS-CoV-2). Unlike SARS-CoV, MERS-CoV and SARS-CoV-2 that are associated with severe respiratory disease, the four common HCoVs (229E, OC43, NL63, and HKU1) generally cause mild to moderate upper-respiratory tract illness, presumably contributing to 15%–30% of cases of common colds in human.
Abstract
Seven human coronaviruses (HCoVs) have been so far identified, namely HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and the novel coronavirus (2019-nCoV, a.k.a. SARS-CoV-2). Unlike the highly pathogenic SARS-CoV, MERS-CoV, and 2019-nCoV, the four so-called common HCoVs generally cause mild upper-respiratory tract illness and contribute to 15%–30% of cases of common colds in human adults, although severe and life-threatening lower respiratory tract infections can sometimes occur in infants, elderly people, or immunocompromised patients. In this article, we review the molecular virology of these common HCoVs, and summarize current knowledge on HCoV-host interaction, pathogenesis, and other clinically relevant perspectives.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204879/