Background: In 2005-2006 Reunion Island experienced a massive outbreak of chikungunya, a mosquito-borne alphavirus infection. During this epidemic, early neonatal cases were observed with a highly probable mother-to-child transmission.
Methods: A retrospective descriptive study was conducted in 5 neonatal medicine departments. Chikungunya virus infection was confirmed by reverse transcription-polymerase chain reaction or specific serology in mothers and their newborns. Mothers were screened if they presented signs at delivery or if their neonates became ill on the first days of life.
Results: Thirty-eight neonates were enrolled. All mothers, except 2 asymptomatic mothers, presented signs during the perinatal period (range, day(D) -4 to D+1). All neonates were symptomatic and presented symptoms on D3 to D7 (mean, D4). The mean interval between onset of maternal illness and onset of neonatal illness was 5 days (range, 3-9). The most frequent clinical signs in neonates were fever (79%), pain (100%), rash (82%), and peripheral edema (58%). Thrombocytopenia (76%), lymphopenia (47%), decreased prothrombin value (65%), and elevation of aspartate aminotransferase (77%) were detected. Complications included seizures (6), hemorrhagic syndrome (6), and hemodynamic disorders (10). Reverse transcription-polymerase chain reaction in cerebrospinal fluid was positive in 22 of 24 cases, and abnormal findings on brain magnetic resonance imaging (14 of 25) with white matter lesions or intraparenchymal hemorrhages or both were found. Echocardiography (16) showed myocardial hypertrophy (5), ventricular dysfunction (2), pericarditis (2), and coronary artery dilatation (6). One neonate died of necrotizing enterocolitis.
Conclusions: The chikungunya epidemic that occurred on La Reunion Island revealed for the first time the possibility of mother-to-child transmission in the perinatal period with a high rate of morbidity.