Herpes simplex encephalitis in infants.

Two cases are reported of severe encephalitis in infants that were caused by a primary infection with herpes simplex virus type 1. Both patients presented with focal seizures; the clinical diagnosis was confirmed by the rapid appearance of IgM antibody to herpes simplex virus type 1 in cerebrospinal fluid and serum. In spite of the early use of acyclovir, which was administered by the intravenous route, the clinical response was poor and both infants were left with severe neurological impairment.