RESUMO
Despite increased malaria control efforts, school-aged children (5-14 years) have higher a malaria prevalence compared to children under-five. In high-transmission settings, up to 70% of school-aged children harbour malaria parasitaemia and therefore contribute significantly to the reservoir for transmission. A systematic review was performed to explore the correlation between the malaria parasite carriage in pregnant women and school-aged children living in similar endemic settings of sub Saharan Africa to inform strategies to improve targeted malaria control. In order to obtain data on malaria prevalence in pregnant women and school-aged children living in the same endemic setting, we searched the Malaria in Pregnancy Library, PubMed, Cochrane library and Web of Science in December 2018. We fit a fixed effect model to obtain a pooled risk ratio (PRR) of malaria in school-aged children versus pregnant women and used Poisson regression to estimate risk ratios in school-aged children for every increase in prevalence in pregnant women. We used data from six (out of 1096) sources that included 10 data points. There was a strong linear relation between the prevalence of malaria infection in pregnant women and school-aged children (r = 0·93, p < 0·0001). School-aged children were nearly twice at risk to carry parasites compared to pregnant women (RR = 1.95, 95% CI: 1·69-2.25, p < 0.01). Poisson regression showed that a 1% increase in prevalence of malaria infection in pregnant women was significantly associated with increase in risk in school-aged children by 4%. Malaria infection prevalence in school-aged children is strongly correlated with the prevalence in pregnant women living in the same community, and may be considered as alternative indicators to track temporal and spatial trends in malaria transmission intensity. Chemoprevention strategies targeting school-aged children should be explored to reduce malaria burden and transmission in school-aged children and its potential impact on communities.
RESUMO
Sulfadoxine/pyrimethamine (SP) is still used for malaria control in sub-Saharan Africa; however, widespread resistance is a major concern. This study aimed to determine the dispersal and origin of sulfadoxine resistance lineages in the Democratic Republic of the Congo compared with East African Plasmodium falciparum dihydropteroate synthetase (Pfdhps) haplotypes. The analysis involved 264 isolates collected from patients with uncomplicated malaria from Tanzania, Uganda and DR Congo. Isolates were genotyped for Pfdhps mutations at codons 436, 437, 540, 581 and 613. Three microsatellite loci (0.8, 4.3 and 7.7 kb) flanking the Pfdhps gene were assayed. Evolutionary analysis revealed a shared origin of Pfdhps haplotypes in East Africa, with a distinct population clustering in DR Congo. Furthermore, in Tanzania there was an independent distinct origin of Pfdhps SGEGA resistant haplotype. In Uganda and Tanzania, gene flow patterns contribute to the dispersal and shared origin of parasites carrying double- and triple-mutant Pfdhps haplotypes associated with poor outcomes of intermittent preventive treatment during pregnancy using SP (IPTp-SP). However, the origins of the Pfdhps haplotypes in DR Congo and Eastern Africa sites are different. The genetic structure demonstrated a divergent and distinct population cluster predominated by single-mutant Pfdhps haplotypes at the DR Congo site. This reflects the limited dispersal of double- and triple-mutant Pfdhps haplotypes in DR Congo. This study highlights the current genetic structure and dispersal of high-grade Pfdhps resistant haplotypes, which is important to guide implementation of SP in malaria chemoprevention strategies in the region.