Malaria and pregnancy in Mfou, Cameroon: Epidemiology and immune responsiveness
Description
Malaria is an important public health problem in the tropics where pregnant women are at a higher risk of infection and disease than non-pregnant women. In order to plan and implement successful antimalarial strategies aimed at pregnant women, more knowledge of the epidemiology and immunology of malaria during pregnancy is required. The interaction between Plasmodium falciparum infection and pregnancy, and the potential mechanisms for the pregnancy-related alterations in the immune response to malaria were investigated in a study conducted in Mfou, a rural community in Cameroon. It consisted of both cross-sectional and longitudinal analyses involving two hundred and twenty-five (225) pregnant women and seventy-five non-pregnant controls. Information was obtained by interview using a questionnaire and blood samples were collected from each woman for parasitologic examination and serologic reactivity to intraerythrocytic malarial antigens, ring-infected erythrocyte surface antigen (RESA) and circumsporozoite (CS) protein by immunofluorescent antibody assay (IFA), modified immunofluorescent antibody assay (MIFA) and enzyme-linked immunosorbent assay (ELISA), respectively. In addition, the pattern of antimalarial drug use and the effect of chloroquine on parasitemia were determined The results showed that P. falciparum malaria occurred more frequently in pregnant than in non-pregnant women in terms of parasite rates (p = 0.03) and density (p = 0.003), especially in primigravidae as compared to multigravidae. Failure to clear parasitemia after a chloroquine regimen was more frequent in pregnant as compared to non-pregnant women (p $$ 0.05), and no correlation with parasitemia was found. In contrast, anti-RESA antibody titers were significantly lower in pregnant than in non-pregnant women (p = 0.02), in primigravidae than in multigravidae (p = 0.002), and were inversely correlated with parasitemia (r = $-$0.36; p $<$ 0.01). These data suggest that the increased susceptibility to malarial infection in pregnant women can be partially explained by lower reactivity to RESA