ABSTRACT
A male infant was admitted because of fever. He was born at 37-weeks' gestation. His mother had experienced acute febrile illness with headache and myalgia. Her illness persisted with onset of active labor pain on day 5, which prompted cesarean section; postoperatively, the hematocrit decreased, requiring transfusion. The infant was well until fever developed at 16 hours after birth. There were petichiae on his face and trunk and the liver was enlarged. Fever subsided on day 5 without evidence of plasma leakage or severe hemorrhage. He made an uneventful recovery after 8 days of illness. Leukopenia and thrombocytopenia were present in the mother and infant. Both were diagnosed as dengue fever. Dengue type 1 was recovered from the infant by polymerase chain reaction. The dengue enzyme-linked immunoassay showed secondary infection in the mother and primary infection in the infant. In dengue-endemic areas, clinicians should be alert to dengue fever/dengue hemorrhagic fever in pregnant women presenting with acute febrile illness, and be prepared for proper management.