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.
According to a study at the Mayo Clinic, picornaviruses can "cross over" into the brain, causing memory
loss and other neurological symptoms.
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, Ljungan virus
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.