Identification of Plasmodium DNA sequences in anopheline samples from the rural settlement of Santa Luzia, municipality of Cruzeiro do Sul, state of Acre, Brazil

Female Anophelines may be naturally infected by one or more species of Plasmodium and, through their bites, transmit this parasite, whose infection results in malaria in humans. The transmission dynamics depend on several factors, including the vector species, and therefore differ from region to region. Landscapes impacted by deforestation and collections of shaded, low-flow, clean water, which are often found in the Brazilian Amazon, are the preferred locations for malaria vectors. In most endemic regions, infection by Plasmodium vivax and Plasmodium falciparum is the main cause of malaria, with geographical variation in proportion, depending on the susceptibility of the specific population. The main vector of malaria in Brazil, in addition to other vectors that can transmit the disease, is Anopheles darlingi, which is widely distributed throughout the Amazon. Despite considerable progress in the elimination, control, and understanding of malaria in South America, the disease remains a major public health problem in Brazil.

METHODS: The project will be carried out in the Santa Luzia Settlement, municipality of Cruzeiro do Sul, Acre. Anophelines will be collected and identified morphologically and molecularly. Individual samples of identified anophelines will be processed for genomic DNA extraction using a non-destructive nucleic acid extraction technique. Subsequently, Plasmodium species will be detected and identified using conventional PCR and real-time PCR assays, using fluorescein-labeled probes and cytb markers. Cumulative deforestation and forest cover will be estimated using Landsat satellite images (Landsat 1-8) according to a protocol developed by the group. The method consists of supervised classification of landscape composition into distinct classes: soil water collection, native dense rainforest, secondary vegetation, exposed soil and pasture, urban soil with buildings and pavement. Accumulated deforestation will be measured as the inverse of native forest cover over time and may vary between 0% (completely preserved) and 100% (absolutely degraded). The generalized linear Poisson regression model will be used to test the hypothesis of an association between the time of deforestation and the occurrence of natural infection in mosquitoes. This same model will be used to estimate the risk of transmission as a function of accumulated deforestation.

EXPECTED RESULTS: Based on the data collected in this research, we intend to collaborate in the promotion and creation of public policies for planning and controlling malaria in Brazil and for conserving the Amazon rainforest.

Project details

Genetics and Genomics
Measurement of Transmission
Modeling

Nov 2024 — Oct 2026

Brazil