Exploring malaria vector diversity on the Amazon Frontier

Brian P Bourke,Leonardo S M Chaves,Maria A M Sallum,Eduardo S Bergo,Tatiane M P de Oliveira,Gabriel Z Laporta,Jan E Conn

doi:10.1186/s12936-018-2483-2

Abstract

BackgroundDeforestation in the Amazon and the social vulnerability of its settler communities has been associated with increased malaria incidence. The feeding biology of the most important malaria vectors in the region, notably Nyssorhynchus darlingi, compounds efforts to control vectors and reduce transmission of what has become known as “Frontier Malaria”. Exploring Anophelinae mosquito diversity is fundamental to understanding the species responsible for transmission and developing appropriate management and intervention strategies for malaria control in the Amazon River basin.MethodsThis study describes Anophelinae mosquito diversity from settler communities affected by Frontier Malaria in the states of Acre, Amazonas and Rondônia by analysing COI gene data using cluster and tree-based species delimitation approaches.ResultsIn total, 270 specimens from collection sites were sequenced and these were combined with 151 reference (GenBank) sequences in the analysis to assist in species identification. Conservative estimates found that the number of species collected at these sites was between 23 (mPTP partition) and 27 (strict ABGD partition) species, up to 13 of which appeared to be new. Nyssorhynchus triannulatus and Nyssorhynchus braziliensis displayed exceptional levels of intraspecific genetic diversity but there was little to no support for putative species complex status.ConclusionsThis study demonstrates that Anophelinae mosquito diversity continues to be underestimated in poorly sampled areas where frontier malaria is a major public health concern. The findings will help shape future studies of vector incrimination and transmission dynamics in these areas and support efforts to develop more effective vector control and transmission reduction strategies in settler communities in the Amazon River basin.

Highlights

Deforestation in the Amazon and the social vulnerability of its settler communities has been associated with increased malaria incidence
An emerging public health consensus is that the dynamics of malaria in the Amazon River basin is unstable, with waves of disease emergence accompanied by explosive epidemics in many localities
The current study aims to describe Anophelinae species diversity in rural settlements affected by frontier malaria in the Amazon River basin, employing clustering-based

Summary

Introduction

Deforestation in the Amazon and the social vulnerability of its settler communities has been associated with increased malaria incidence. Ongoing anthropogenic changes in the environment, which alter the abiotic characteristics and ecology of larval habitats [16], lead to an increase in abundance of the most important vector species and, higher biting rates and Plasmodium infection in settler communities with poor housing conditions, lack of access to health services and low or no immunity to the pathogens [17]. An emerging public health consensus is that the dynamics of malaria in the Amazon River basin is unstable, with waves of disease emergence accompanied by explosive epidemics in many localities These are usually associated with changes to natural environments and ecologies, waves of economic development, and migratory influxes between endemic and non-endemic areas. This dynamic process has challenged control programmes developed to mitigate the burden of malaria in the Amazon [22]

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