Enterovirus

The genus Enterovirus (EV) belonging to the Picornaviridae family comprises 13 species, of which seven are human viruses. Four of the species are: (1) EV-A such as coxsackievirus (CV)-A6, CV-A10, CV-A16 and EV-A71, (2) EV-B such as the CV-B viruses, echoviruses (ECHO) and CV-A9, (3) EV-C such as polioviruses (PV) and CV-A21, (4) EV-D such as EV-D68 and EV-D70. The other three species are rhinoviruses RV-A, RV-B and RV-C which comprised over 100 different numbered RVs. Infection with enteroviruses can cause numerous clinical conditions including poliomyelitis, meningitis and encephalitis, hand-foot-and-mouth disease, acute flaccid paralysis, diarrhea, myocarditis and respiratory illness.

Enteroviruses are small, nonenveloped, positive-sense, single-stranded RNA viruses with an icosahedral capsid. The genome of ∼7.5 kb encodes a single polyprotein that is autoprocessed into structural proteins (VP1, VP2, VP3, and VP4), nonstructural proteins (2A, 2B, 2C, 3A, 3B, 3C, and 3D), and several functional processing intermediates. The viral nonstructural proteins, particularly the protease 3C^pro and the RNA-dependent RNA polymerase 3D^pol, are attractive targets for antiviral drug development.