Microevolution in Anopheles cruzii (Diptera: Culicidae) mosquitoes

• Grant number: 16/16647-1
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2017
• End date: April 30, 2019
• Field of knowledge: Biological Sciences - Parasitology - Entomology and Malacology of Parasites and Vectors
• Principal Investigator: Mauro Toledo Marrelli
• Grantee: Mauro Toledo Marrelli
• Host Institution: Faculdade de Saúde Pública (FSP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: André Barretto Bruno Wilke

Abstract

In Brazil, malaria occurs into two distinct epidemiological patterns: malaria transmitted in the Amazon region mainly by Anopheles darlingi mosquitoes and malaria transmitted in the Atlantic Forest region, mainly by Anopheles cruzii mosquitoes. Recent studies have found high prevalence of humans exposed to Plasmodium among blood donors in the city of São Paulo metropolitan area, as well as An. Cruzii infected with Plasmodium in nearby Atlantic forest fragments. Behavior studies of An. cruzii suggest a clear epidemiological pattern: mosquitoes collected in tree canopies undergo a simian zoonotic cycle of malaria, without the presence of human cases; mosquitoes collected at ground level maintains an enzootic cycle, blood feeding both in simians and humans, resulting in human cases of malaria. The pattern found among populations of An. Cruzii suggest that there is a well-defined structure in two distinct populations with clear epidemiological implications. The relatively low number of cases apparently can be explained by the fact that An. Cruzii living in tree canopies do not blood feed in humans, thus preventing an outbreak of malaria, but this paradigm is crumbling because of urbanization processes and deforestation. There are no studies on population genetics of this species and the relationship between their population structure and epidemiological patterns remains unknown. Considering the intrinsic An. cruzii epidemiological importance in malaria transmission, the objective of this project is to analyze the population structure of An. cruzii mosquitoes from the Environmental Protection Area Capivari-Monos, and the Cantareira State Park, located in the city of São Paulo, using microsatellite loci and wing geometric morphometry. The correlation between population structure, exogenous and endogenous variables can lead to better understanding of An. cruzii population dynamics and consequently elucidate malaria transmission processes in the three urban strata (urban, peri-urban and wild). Key features to maintaining the effectiveness of malaria control measures. (AU)