Picornaviridae

A family of very small (20–30 nm) ether-resistant, nonenveloped viruses having a core of positive sense single-stranded infectious RNA enclosed in a capsid of icosahedral symmetry with 60 capsomeres. Numerous species (including the polioviruses, coxsackieviruses, and echoviruses) are included in the family. There are five accepted genera : Enterovirus, Rhinovirus, Hepatovirus, Cardiovirus, and Aphthovirus. [It. piccolo, very small, + RNA + -viridae]

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Pi·cor·na·vi·ri·dae (.)pē-.kȯr-nə-'vir-ə-.dē n pl a family of small single-stranded RNA viruses that have an icosahedral virion with no envelope and that include the causative agents of avian encephalomyelitis, encephalomyocarditis, hepatitis A, poliomyelitis, foot-and-mouth disease, and hand, foot and mouth disease see coxsackievirus, echovirus, enterovirus, rhinovirus

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Pi·cor·na·vi·ri·dae (pĭ-kor″nə-virґĭ-de) the picornaviruses: a family of RNA viruses having a nonenveloped icosahedral virion 22–30 nm in diameter without surface features. The genome consists of a single molecule of positive-sense single-stranded RNA (MW approximately 2.5 Ч 10⁶, size 7.2–8.5 kb). Viruses contain four major polypeptides and are resistant to lipid solvents but sensitive to ultraviolet radiation. Replication and assembly occur in the cytoplasm; virions are released by cell destruction. Host range is narrow and transmission is chiefly mechanical. Genera of medical or veterinary importance include Aphthovirus, Cardiovirus, Enterovirus, Hepatovirus, Parechovirus, and Rhinovirus.