Abstract

The family of Coronaviridae was defined around 1968, primarily by morphologic criteria. The virions are pleomorphic to spherical-shaped particles (120–160 nm diameter), which are surrounded by a fringe of club- or pear-shaped surface projections (12–24 nm long; Figure 1). The virus has a lipid envelope and contains a single-stranded RNA genome of positive polarity. Coronaviruses infect humans, mammals and birds. Based on molecular criteria, the toroviruses represent a second genus within this family. Furthermore, evolutionary relationships to the Arteriviridae are discussed within the concept of a ‘coronavirus-like’ superfamily.

Keywords

Coronaviridae, virions, coronavirus, Arteriviridae

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