A 36 year old primigravid woman presented with a ''flu-like'' illness
and premature labour, followed by severe pneumonitis and hepatitis in
the late second trimester of pregnancy. Progressive deterioration obli
ged an elective delivery of twins, stillborn at 25 weeks of gestation.
Herpes virus isolated from one placenta, but not from any fetal tissu
e, was the only indication of a systemic herpes simplex infection in w
hich there were no mucocutaneous lesions seen before or during the ill
ness. There was no history of herpes simplex infection and antibody st
udies were not helpful initially for a diagnosis that was confirmed in
retrospect. Double staining for viral DNA and antigen showed that the
virus was present in host monocytes.