Outbreak of severe neurologic involvement associated with Enterovirus 71 infection.

Enterovirus 71 has been associated with several outbreaks, as well as sporadic cases, of central nervous system infection and has a worldwide distribution. Seven children with encephalitis and five with aseptic meningitis caused by Enterovirus 71 were seen at Otsu Municipal Hospital during the summer of 1997. The infections were confirmed serologically, although detection of the viral genome in cerebrospinal fluid was unsuccessful. Seven children were diagnosed as having hand-foot-and-mouth syndrome, two were diagnosed as having herpangina, and three patients younger than 12 months old developed no eruptions. The skin or mucosal manifestations of this outbreak demonstrated considerable variation. The Enterovirus 71 strain that caused the outbreak had a strong neurovirulent tendency. Among the patients with encephalitis, symptoms originating from the impairment of diencephalon were seen in four patients, and those originating from cerebellar impairment were seen in two patients. Brain magnetic resonance imaging in one patient revealed an abnormality in the pons. The neurologic manifestations associated with Enterovirus 71 infection may be characterized by involvement of the cerebellum, brainstem, and diencephalon. Enterovirus 71 is one of the pathogenic viruses that cause hand-foot-and-mouth syndrome, as well as a variety of other clinical manifestations. The most important of these is neurologic disease, especially in infants and young children.