False-colour transmission electron micrograph of coxsackieviruses, named after the town in the USA where they were isolated. They belong to the genus of Enteroviruses. This genus is part of the Picornaviridae group, which contains the small (22 nanometers), non-enveloped, icosahedral viruses. Coxsackieviruses, of which there are many types, cause diseases such as aseptic meningitis; herpangina, an acute pharyngitis; hand, foot & mouth disease (not foot & mouth); epidemic myalgia or Bornholm disease; and myocarditis of newborn babies. They are also among the miscellaneous viruses that cause colds.