Scientific bases for residual malaria elimination in the Brazilian Amazon

Abstract

With 143,910 laboratory-confirmed cases and 41 malaria-related deaths in 2014, Brazil has now the lowest malaria burden in 35 years, with transmission virtually limited to the Amazon Basin. Accordingly, the Ministry of Health of Brazil has launched, in November 2015, the Malaria Elimination Plan, with the short-term goal of interrupting Plasmodium falciparum transmission countrywide over the next 15 years. The focal nature of malaria transmission in Brazil suggests that elimination efforts will require a careful prioritization of a few residual malaria pockets. Here we combine classical epidemiological approaches, to characterize risk factors and intervention targets, with population genetics/genomics analyses of parasites and studies of vector biology and control, with the ultimate goal of improving current strategies for malaria control and elimination in Brazil. Our field-based studies in the main endemic area of Brazil (Juruá Valley, close to the border with Peru, which accounts for 20% of all infections in this country) are complemented with mathematical modelling of different malaria elimination scenarios. We focus on two main challenges for malaria elimination: (a) the presence of asymptomatic infections with low-level parasitemias that are often below the detection threshold of available diagnostic techniques, creating a large and undetected reservoir of infection, and (b) the maintenance of high vector densities resulting from new man-made mosquito breeding sites (fish pounds opened across Juruá Valley for commercial aquaculture). (AU)