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Malaria remains a public health priority in Rwanda. The use of insecticide-treated nets (ITNs) is a key malaria prevention tool. However, expanding pyrethroid resistance threatens the gains made in malaria control. In 2018, the Rwandan malaria program strategic approach included the use of newer types of ITNs such as pyrethroid plus piperonyl butoxide (PBO) synergist-treated nets to counter pyrethroid resistance. In February 2020, 5,892,280 ITNs were distributed countrywide; 1,085,517 of these were PBO nets distributed in five districts. This study was a pragmatic observational study that leveraged the 2020 net distribution and routinely collected confirmed malaria cases to determine the impact of PBO nets 1 and 2 years after ITN distribution. No differences were observed in the average net coverage between the PBO and standard net districts. A significant reduction in malaria incidence was reported in both the PBO (P = 0.019) and two control districts that received standard nets (P = 0.008) 1 year after ITN distribution. However, 2 years after, this reduction was sustained only in the PBO (P = 0.013) and not in the standard net districts (P = 0.685). One year after net distribution, all districts had a significant reduction in malaria incidence rate (incidence rate ratio < 1). In the second year, incidence in districts with PBO nets continued to decrease, whereas in districts with standard nets, incidences were similar to predistribution levels. The results indicate that PBO nets are a promising tool to combat pyrethroid resistance in Rwanda, with protective effects of up to 2 years post distribution.

Intermittent preventive therapy during pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended in areas of moderate to high malaria transmission intensity. As a result of the increasing prevalence of SP resistance markers, IPTp-SP was withdrawn from Rwanda in 2008. Nonetheless, more recent findings suggest that SP may improve birthweight even in the face of parasite resistance, through alternative mechanisms that are independent of antimalarial effects. The prevalence of single nucleotide polymorphisms in Plasmodium falciparum dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr) genes associated with SP resistance among 148 pregnant women from 2016 to 2018 within Rwanda's Southern Province (Huye and Kamonyi districts) was measured using a ligase detection reaction-fluorescent microsphere assay. The frequency of pfdhps K540E, A581G, and the quintuple (pfdhfr N51I + C59R + S108N/pfdhps A437G + K540E) and sextuple (pfdhfr N51I + C59R + S108N/pfdhps A437G + K540E + A581G) mutant genotypes was 90%, 38%, 75%, and 28%, respectively. No significant genotype difference was seen between the two districts, which are approximately 50 km apart. Observed agreements for matched peripheral to placental blood were reported and found to be 207 of 208 (99%) for pfdhfr and 239 of 260 (92%) for pfdhps. The peripheral blood sample did not miss any pfdhfr drug-resistant mutants or pfdhps except at the S436 loci. At this level of the sextuple mutant, the antimalarial efficacy of SP for preventing low birthweight is reduced, although overall SP still exerts a nonmalarial benefit during pregnancy. This study further reveals the need to intensify preventive measures to sustain malaria control in Rwanda to keep the overall incidence of malaria during pregnancy low.

The impressive decline in child mortality that occurred in Rwanda from 1996-2000 to 2006-2010 coincided with a period of rapid increase of malaria control interventions such as indoor residual spraying (IRS); insecticide-treated net (ITN) distribution and use, and improved malaria case management. The impact of these interventions was examined through ecological correlation analysis, and robust decomposition analysis of contextual factors on all-cause child mortality. Child mortality fell 61% during the evaluation period and prevalence of severe anemia in children 6-23 months declined 71% between 2005 and 2010. These changes in malaria morbidity and mortality occurred concurrently with a substantial increase in vector control activities. ITN use increased among children under five, from 4% to 70%. The IRS program began in 2007 and covered 1.3 million people in the highest burden districts by 2010. At the same time, diagnosis and treatment with an effective antimalarial expanded nationally, and included making services available to children under the age of 5 at the community level. The percentage of children under 5 who sought care for a fever increased from 26% in 2000 to 48% in 2010. Multivariable models of the change in child mortality between 2000 and 2010 using nationally representative data reveal the importance of increasing ITN ownership in explaining the observed mortality declines. Taken as a whole, the evidence supports the conclusion that malaria control interventions contributed to the observed decline in child mortality in Rwanda from 2000 to 2010, even in a context of improving socioeconomic, maternal, and child health conditions.