Severe Generalized Epidemic Myalgia in an Adult due to Human Parechovirus Type 3: A Case Report

Parechovirus A type 3 (PeVA3) is most commonly transmitted to adults from children. Although PeVA3 infection is rarely diagnosed, as the symptoms are generally mild and self-limiting, this infection has been associated with epidemic myalgia in Japan. The patient, a 37-year-old man, presented with severe generalized myalgia, inability to open his mouth, and orchitis, which resolved over a period of 10 days. All members of his family were thought to have been infected with PeVA3 during a visit to an amusement park. Although the source of infection and inability to open his mouth are atypical, the acute generalized muscle symptoms made us suspect epidemic myalgia and enabled us to make a diagnosis of PeVA3 infection.