Dynamics of Persistent Submicroscopic and Microscopic Plasmodium falciparum in Pregnant Women Under Intermittent Preventive Treatment: A Study Cohort in Benin.

Abstract

Background: Malaria infections in pregnancy are a major cause of maternal morbidity and neonatal mortality in sub-Saharan Africa. A high proportion of these infections are submicroscopic, which are usually asymptomatic and therefore untreated during pregnancy. Intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) aims to prevent and treat all potential infections whether submicroscopic or not. However, the resistance of parasites to SP is steadily increasing. The dynamic of microscopic and submicroscopic infections in a cohort of Beninese women throughout their pregnancy and its relation to IPTp-SP has been assessed.

Methods: As a subsample of the RECIPAL project, 130 women with at least 2 infections detected by polymerase chain reaction during their pregnancy were included. Infections were categorized as new (isolated) or persistent based on msp-2 genotyping, where persistent infections had identical genotypes in all studied time points. Submicroscopic infections were defined as polymerase chain reaction-positive and thick blood smear-negative. The persistence of infections according to IPTp-SP uptake was assessed.

Results: A total of 73.1% of women (95 women of 130) had exclusively persistent infections throughout their pregnancy, whereas only 7.7% (10 of 130) had exclusively new infections. During pregnancy, the median time spent with 1 persistent infection was 7.2 weeks. A considerable proportion of these persistent infections 64.3% (72 of 113) was only submicroscopic. Approximately 20% of these persistent infections occurred despite the use of IPTp-SP.

Conclusions: Using new antimalarial combinations could contribute to limit the persistence of submicroscopic infections and their probable negative effects on the mother and the fetus.