Picornaviridae

Introduction

Picornaviruses are viruses that belong to the family Picornaviridae. The name picornavirus means small RNA virus. Picornaviruses are non-enveloped, positive-stranded RNA viruses with an icosahedral capsid. The genome RNA is unusual because it has a protein on the 5' end that is used as a primer for transcription by RNA polymerase.

Picornaviruses include two main categories: the enteroviruses and the rhinoviruses. Some important enteroviruses are poliovirus and Hepatitis A virus. Enteroviruses infect the enteric tract as it is visible from its name. On the other hand, Rhinoviruses infect primarily the nose and the throat. Enteroviruses replicate at 37°C, whereas Rhinoviruses grow better at 33°C, as this is the lower temperature of the nose. Enteroviruses are stable under acid conditions and thus they are able to survive exposure to gastric acid. In contrast, Rhinoviruses are acid-labile and that is the reason why Rhinoviruses are restricted to the nose and throat.

They include the following genera:

Genus Enterovirus; type species: Poliovirus
Genus Rhinovirus; type species: Human rhinovirus A (common cold)
Genus Hepatovirus; type species: Hepatitis A virus
Genus Cardiovirus; type species: Encephalomyocarditis virus
Genus Aphthovirus; type species: Foot-and-mouth disease virus
Genus Parechovirus; type species: Human parechovirus
Genus Erbovirus; type species: Equine rhinitis B virus
Genus Kobuvirus; type species: Aichi virus
Genus Teschovirus; type species: Porcine teschovirus

The name is derived from pico meaning small (10^-12m), and RNA referring to the ribonucleic acid genome.

References

Viruses | Picornaviruses

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Introduction

References