Vertical maternal fetal transmission of the chikungunya virus. Ten cases among 84 pregnant women

INTRODUCTION: In March 2005, an epidemic of chikungunya virus began in the southern portion of Reunion Island (French overseas district in the Indian Ocean) and spread to the northern part of the island at the end of 2005. The Reunion-South Hospital Group observed the first cases of pregnant women infected with the virus in June 2005. We report here for the first time maternal-fetal transmission of this virus. CASES: From June 2005 through the end of January 2006, 84 pregnant women had acute chikungunya infections during pregnancy. In 88% of these cases (n=74)--all involving infections relatively distant from delivery--the newborns appeared asymptomatic. Conversely, 10 newborns had severe attacks (4 with meningoencephalitis and 3 with intravascular coagulations) after birth and required prolonged neonatal hospitalization (6 in the neonatal intensive care unit with intubation and assisted ventilation). No infants died, but there was one case of severe intracerebral hemorrhage after severe thrombocytopenia. These cases were confirmed by specific serology testing or PCR or both for mothers and newborns. We note that all severe cases involved women with viremia and fever in the intrapartum period.