New highland distribution records of multiple Anopheles species in the Ecuadorian Andes

Lauren L Pinault,Fiona F Hunter

doi:10.1186/1475-2875-10-236

Abstract

BackgroundSeveral recent climate change reviews have stressed the possibility of some malaria vectors occupying regions of higher altitudes than previously recorded. Indeed, highland malaria has been observed in several African nations, possibly attributable to changes in land use, vector control and local climate. This study attempts to expand the current knowledge of the distribution of common Anopheles species in Ecuador, with particular attention to highland regions (> 500 m) of the Andes.MethodsExtensive field collections of larvae were undertaken in 2008, 2009 and 2010 throughout all regions of Ecuador (except the lower-altitude Amazonian plain) and compared to historical distribution maps reproduced from the 1940s. Larvae were identified using both a morphological key and sequencing of the 800 bp region of the CO1 mitochondrial gene. In addition, spatial statistics (Getis-Ord Hotspot Analysis: Gi*) were used to determine high and low-density clusters of each species in Ecuador.ResultsDistributions have been updated for five species of Anopheles in Ecuador: Anopheles albimanus, Anopheles pseudopunctipennis, Anopheles punctimacula, Anopheles eiseni and Anopheles oswaldoi s.l.. Historical maps indicate that An. pseudopunctipennis used to be widespread in highland Andean valleys, while other species were completely restricted to lowland areas. By comparison, updated maps for the other four collected species show higher maximum elevations and/or more widespread distributions in highland regions than previously recorded. Gi* analysis determined some highland hot spots for An. albimanus, but only cold spots for all other species.ConclusionsThis study documents the establishment of multiple anopheline species in high altitude regions of Ecuador, often in areas where malaria eradication programs are not focused.

Highlights

Several recent climate change reviews have stressed the possibility of some malaria vectors occupying regions of higher altitudes than previously recorded
The purpose of this paper is to identify the extent of previously lowland-restricted malaria vectors within highland regions of the Andes and to update distribution maps of the most common Anopheles species in Ecuador
Other anopheline species have been reported in Ecuador [16,17], only five species were collected during the three years of intensive field work: Anopheles albimanus, An. pseudopunctipennis, Anopheles punctimacula, Anopheles eiseni and Anopheles oswaldoi s.l

Summary

Introduction

Several recent climate change reviews have stressed the possibility of some malaria vectors occupying regions of higher altitudes than previously recorded. Highland malaria has been observed in several African nations, possibly attributable to changes in land use, vector control and local climate. The purpose of this paper is to identify the extent of previously lowland-restricted malaria vectors within highland regions of the Andes and to update distribution maps of the most common Anopheles species in Ecuador. These maps will identify highland areas, as well as low-altitude areas where Anopheles were recently collected, and thereby provide valuable data for malaria control in the country. All five species are found in other countries in Central and South America [18,19,20]

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