Picornavirus

Picornavirus is a family of viruses in the order Picornavirales, in the realm Riboviria. They are non-enveloped, positive-sense, single-stranded RNA viruses with an icosahedral capsid. The name is derived from pico, meaning small, and RNA, referring to the ribonucleic acid genome, so "picornavirus" literally means small RNA virus.

Taxonomy

The family Picornaviridae includes a number of important human pathogens in the genera Enterovirus (which includes polioviruses, coxsackieviruses, and echoviruses), Rhinovirus, Hepatovirus (which includes Hepatitis A virus), and others. The family also includes a number of viruses that infect animals.

Structure and genome

Picornaviruses are small, with a diameter of about 22–30 nanometers. The capsid is composed of 60 copies each of four different viral proteins for a total of 240 molecules arranged in an icosahedral symmetry. The genome is a single molecule of linear, positive-sense, single-stranded RNA.

Replication

Picornaviruses replicate in the cytoplasm of the host cell. The RNA genome is translated into a single, large polyprotein, which is then cleaved by viral proteases to produce the individual viral proteins.

Diseases

Picornaviruses are responsible for a wide variety of diseases in humans and animals. In humans, they can cause common colds, meningitis, hepatitis, and poliomyelitis. In animals, they can cause foot-and-mouth disease and encephalomyocarditis.

See also

• Virus classification
• Viral replication
• Viral diseases

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