The group A coxsackieviruses have been conspicuous among the agents isolated from infants and children with focal enteroviral encephalitis. The nonpolio enteroviruses rarely cause a syndrome of acute motor weakness and paralysis that is clinically and pathologically indistinguishable form poliomyelitis, although myelitis caused by the nonpolio enteroviruses is less severe, muscle weakness is less likely to persist and bulbar involvement is less common. Enterovirus 71 is known to have been responsible for large outbreaks of acute paralysis involving hundreds of individuals, mostly children. Enteroviral myopericarditis is clinically indistinguishable from disease caused by other cardiotropic viruses, including adenoviruses, influenza A virus, and mumps virus. Two-thirds of patients report a febrile upper respiratory tract infection preceding symptoms of frank myocarditis, which may include fever, substernal chest pain, exercise intolerance and dyspnea.
Echocardiography confirms the diagnosis.
Cardiac enzymes are elevated. Two enterovirus serotypes have been responsible for widespread epidemics of AHC that have occurred throughout the tropics. In addition, the epidemiology of AHC caused by a variant of coxsackievirus A24 has intertwined with that of enterovirus 70. AHC is transmitted directly form person to person via fingers and fomites. Both viruses are readily isolated from tears but infrequently from other sites.