Human parechovirus (HPeV) belongs to the Picornaviridae family of RNA viruses. 
HPeV infections can be asymptomatic, lead to mild respiratory and/or 
gastrointestinal symptoms, or less frequently cause severe diseases such as 
sepsis, meningitis, encephalitis, and myocarditis. Severe neurological HPeV 
infections occur most commonly in infants and neonates. There are currently 16 
recognized types of HPeV. HPeV type 3 (HPeV3) has been the predominant type 
associated with severe central nervous system disease in neonates and newborns 
since its discovery in 1999. Although HPeV-related infections have been reported 
in adults, symptomatic HPeV3 infections in adolescents and adults are uncommon. 
A case of severe HPeV3 myocarditis and encephalitis in an adolescent is 
described.