Introduction picornavirus Picornaviruses are broken into 3 groups enteroviruses acid-stable most common in children fecal-oral transmission can cause aseptic (viral) meningitis the most common cause of aseptic meningitis in the U.S. can cause acute flaccid paralysis, acute disseminated myelitis, and acute transverse myelitis includes poliovirus coxsackievirus echovirus rhinoviruses not acid-stable grows at 33°C includes rhinovirus hepatovirus hepatitis A virus Characteristics small ("pico-RNA-virus") naked capsid (non-enveloped) resistant to alcohol and detergents highest incidence in summer and fall seasons RNA single-stranded positive-sense linear icosahedral Translation process is unique RNA translated into 1 large polypeptide polypeptide then cleaved to form functional viral proteins