Clinical and laboratory features of congenital malaria in Nigeria

Since congenital malaria had previously been thought to be rare, blood film examination for malaria parasites is still sometimes not routinely performed in ill neonates in malaria-endemic regions. Because of increasing published reports of congenital malaria in Nigeria, there is a need to characterize the clinical and laboratory manifestations associated with malaria parasitemia within the first few hours of life. In a 12-month (April 2003-March 2004), multicenter study in Nigeria, thin and thick blood smears made from maternal (finger prick), placental aspirates, cord blood and neonate (heel prick taken within 4 hours of life) were Giemsa-stained and examined by light microscopy for asexual stages of Plasmodium. Parasitemic neonates were closely monitored for clinical and laboratory features of symptomatic malaria. Plasmodium falciparum was found in 5.1% (95/1875) of neonatal heel pricks; mean parasite density was low (mean=48/mu L, range 8-200/mu L). Antepartum maternal and placental parasitemia were the most important risk factors for congenital parasitemia (P<0.001 andP<0.001). Prolonged labor and prolonged rupture of membranes were also significant factors in the symptomatic neonates. Sixty-one percent (58/95) of parasitemic babies were asymptomatic, while 38.9% (37/95) of them exhibited signs of possible infection. The presence of any symptom was significantly related to parasitemia (P<0.001). Among the symptomatic parasitemic babies the most common symptoms were, fever (temperature>37.5. C) within the first 24 hours of life (100%) and refusal to suck (10.8%). Anemia at birth (hematocrit < 42%) was found in 15.7% (15/95) of parasitemic babies as compared to 9.2% in the non-parasitemic ones. (P=0.03, OR=1.84). The mean hematocrit of parasitemic neonates within 4 hours of life was 49.5 +/- 6.4 as compared to 52.6 +/- 8.2 in non-parasitemic babies (P=0.001). Furthermore, the mean hematocrit was 44.0 +/- 5.5% in the symptomatic parasitemic babies. All symptomatic babies were treated with oral chloroquine with a cure rate of 89.1%. Treatment failures subsequently received oral sulfadoxine-pyrimethamine with good outcome. The febrile newborn should be evaluated for malaria especially if there is a history of prolonged labor or in the presence of maternal malaria infection. Efforts should be intensified to reduce the burden of maternal, placental malaria and therefore congenital malaria.