Dengue virus infection in late pregnancy and transmission to the infants

Background: Vertical dengue virus transmissions have been infrequently described. To date there are no published data on long-term outcome and antibody kinetics of infants who were infected in utero. This is the first report of vertical dengue transmission with 12 months follow-up evolution of antibody and the clinical outcome. Methods: Three mother-infant pairs were confirmed to have perinatally dengue infection by serology, viral isolation, or reverse transcription polymerase chain reaction (RT-PCR). The infants were followed clinically at 1, 2, 4, 6, 9, and 12 months. Sera were collected at 1, 6, and 12 months of age for serologic testing. Results: Three mothers developed symptomatic dengue infection 1 day, 12 days, and 5 weeks before delivery of their infants. The first infant developed presumed bacterial illness on day 6 of life. Dengue virus serotype 1 was detected by RT-PCR and viral isolation. The second infant developed fever, petechiae, and hepatomegaly 9 hours after birth. Dengue virus serotype 2 was detected by RT-PCR. The third infant was asymptomatic. All mothers and infants had uneventful recoveries. One year follow-up revealed normal growth and development in all infants. The pattern of antibody kinetics suggested primary infection in the first and second infants, and the transferred antibody without infection in the third infant. Conclusions: In endemic areas, dengue infection can cause an acute febrile illness in pregnant women and sepsis-like illness in neonates. Vertical infection did not result in long-term sequelae.