MALCODE - Exploring seasonal malaria transmission dynamics and patterns of drug resistance: a molecular epidemiology study in two border areas of Côte d'Ivoire and Burkina Faso

Burkina Faso and Côte d’Ivoire are among the ten countries with the highest malaria burden in the world. Transmission in Burkina Faso and northern Côte d’Ivoire is highly seasonal and intense. In general, malaria infections peak during the wet season and decrease in the dry season. The parasite reservoir that persists until the end of the dry season, as well as importation from other areas, initiates transmission at the beginning of the next wet season. Annual seasonal malaria outbreaks have caused a significant disease burden in the areas for decades. However, researchers have yet to find robust evidence on how parasites persist during the dry season, which is largely unsuitable for malaria transmission, and the relative contribution of the drivers of persistent seasonal malaria transmission remains unknown. In 2012, the World Health Organization (WHO) recommended seasonal malaria chemoprevention (SMC) in areas of high seasonal malaria transmission in the Sahel subregion to prevent malaria in children under five years of age. Burkina Faso immediately implemented SMC, while Côte d’Ivoire did not to date.
However, the widespread use of SMC may select for resistant Plasmodium falciparum variants, potentially reducing the effectiveness of this intervention. It is therefore essential to implement surveillance systems to monitor the spread of molecular markers associated with antimalarial drug resistance. Parasite molecular and genomic data can help elucidating the mechanism of persistent transmission, by quantifying the contribution of asymptomatic and symptomatic infections and drug-resistant parasites to transmission, and by characterizing parasite genetic diversity, population structure, and genetic relatedness. In addition, the impact of interventions such as SMC on the parasite populations and on the evolution of resistance markers can be assessed. Using molecular and genomic tools, this project aims to elucidate mechanisms of persistent transmission, and to look for signs of emerging drug resistance and changes in parasite population structure that could signal a reduction in SMC efficacy in Burkina Faso and provide evidence for the suitability of SMC in northern Côte d’Ivoire. In addition, the prevalence of several other drug resistance markers and their spatial and temporal changes will be investigated. This study will be the first to provide high-resolution micro-epidemiological data on the transmission dynamics of parasite populations in southwestern Burkina Faso and
northern Côte d’Ivoire.

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