Stratification at the health district level for targeting malaria control interventions in Mali

Abstract

Malaria is the leading cause of morbidity and mortality in Mali. Between 2017 and 2020, the number of cases increased in the country, with 2,884,827 confirmed cases and 1454 reported deaths in 2020. We performed a malaria risk stratification at the health district level in Mali with a view to proposing targeted control interventions. Data on confirmed malaria cases were obtained from the District Health Information Software 2, data on malaria prevalence and mortality in children aged 6–59 months from the 2018 Demographic and Health Survey, entomological data from Malian research institutions working on malaria in the sentinel sites of the National Malaria Control Program (NMCP), and environmental data from the National Aeronautics and Space Administration. A stratification of malaria risk was performed. Targeted malaria control interventions were selected based on spatial heterogeneity of malaria incidence, malaria prevalence in children, vector resistance distribution, health facility usage, child mortality, and seasonality of transmission. These interventions were discussed with the NMCP and the different funding partners. In 2017–2019, median incidence across the 75 health districts was 129.34 cases per 1000 person-years (standard deviation = 86.48). Risk stratification identified 12 health districts in very low transmission areas, 19 in low transmission areas, 20 in moderate transmission areas, and 24 in high transmission areas. Low health facility usage and increased vector resistance were observed in high transmission areas. Eight intervention combinations were selected for implementation. Our work provides an updated risk stratification using advanced statistical methods to inform the targeting of malaria control interventions in Mali. This stratification can serve as a template for continuous malaria risk stratifications in Mali and other countries.

Genome-wide SNP analysis of Plasmodium falciparum shows differentiation at drug-resistance-associated loci among malaria transmission settings in southern Mali

“…The association between the complexity of infection and transmission intensity could also be driven by the difference in Anopheles vector densities between rural and urban dwellings (Bendixen et al, 2001). Previous studies have reported lower infection rates and vector densities in Bamako and Nioro compared to the other sites included in this study (Sissoko et al, 2017;Cissoko et al, 2022). Thus, Nioro had the least complex infections but also the shortest transmission season because it is bordering the Sahara.…”

“…Faladje village is located 80 km northwest of Bamako with malaria transmission being both seasonal and perennial. Prevalence of parasitemia ranges from 40 to 50% of the population in the dry season (October–April) and 70–85% in the rainy season (May–September) ( Cissoko et al, 2022 ). The samples (216) spanned the decade from 2007 to 2017, with the largest number (125) from 2013.…”

“…Kenieroba is a village of about 2,000 people and is located approximately 75 km southwest of Bamako ( Cissoko et al, 2022 ). The 89 samples from this site were all collected in 2016.…”

“…Kolle is a rural village of 2,500 people located 55 km southeast of Bamako. Prevalence of parasitemia also ranges from 40 to 50% of the population in the dry season (October–May) and 70–85% in the rainy season (June–September) ( Cissoko et al, 2022 ). This site presented the earliest sample set ( Sangho et al, 2021 ) collected in 2007.…”

“…Despite the decline in malaria incidence from long-term and intensive implementation of these interventions, malaria remains highly endemic across Africa, including Mali. The entire population of Mali is at risk of malaria, although transmission varies across the country’s five geo-climatic zones ( Cissoko et al, 2022 ). Transmission remains high throughout most of the year in the central and southern regions, where more than 90 percent of the population lives, but it is seasonal and epidemic in the desertic North ( PMI, 2020 ).…”