Unexpected disseminated herpes simplex infection in a newborn.

Disseminated herpes simplex virus type 2 was unexpectedly discovered in a baby delivered by primary cesarean section at 36 weeks' gestation prior to rupture of the membranes. The mother was free of orogenital lesions at each prenatal examination. Examination of the placenta revealed chorioamnionitis implicating an ascending infection from the mother's infected genital tract.