Spatial distributions of Anopheles species in relation to malaria incidence at 70 localities in the highly endemic Northwest and South Pacific coast regions of Colombia.

Martha L Ahumada,Eliana F G Cubillos,Lorena I Orjuela,John C Beier,Diana M Cabarcas,Marcela Conde,Sócrates Herrera,Paula X Pareja,Jorge A Lopez,Martha L Quiñones

doi:10.1186/s12936-016-1421-4

Abstract

BackgroundA proper identification of malaria vectors is essential for any attempt to control this disease. Between 40 and 47 Anopheles species have been recorded in Colombia, and eight species complexes have been identified in the last decade. An update of Anopheles species distribution and its relationship with malaria is required, particularly for newly identified members of species complexes.MethodsA cross-sectional entomological study was conducted at 70 localities in the highest malaria transmission areas in Colombia. In each locality, immature and adult mosquitoes were collected. All specimens were determined using morphological characters and confirmed used restriction profiles of Internal Transcribed Spacer 2 (PCR–RFLP-ITS2), and Cytochrome c Oxidase I (COI) sequence gene. To detect natural Plasmodium infections, enzyme-linked immunosorbent assay and nested PCR analysis were used. Distribution of Anopheles species was spatially associated with malaria incidence.ResultsA total of 1736 larvae and 12,052 adult mosquitoes were determined in the 70 localities. Thirteen Anopheles species were identified. COI sequence analysis suggested 4 new lineages for Colombia: for Anopheles albimanus (An. albimanus B), Anopheles pseudopunctipennis s.l., Anopheles neivai (An. neivai nr. neivai 4), and Anopheles apicimacula. Two members of species complexes were identified, as: Anopheles nuneztovari C, and Anopheles albitarsis I. Another seven species were confirmed. Four mosquitoes were infected with Plasmodium species, An. albimanus B and An. nuneztovari C. In Northwest of Colombia, An. nuneztovari C, An. albimanus, and Anopheles darlingi were present in the municipalities with highest annual parasitic index (API) (>35 cases/1000 inhabitants). In the north of South Pacific coast, with a similar API, An. nuneztovari C were widely distributed inland, and the main species in coastal regions were An. albimanus B and An. neivai s.l. In the South Pacific coast bordering with Ecuador, 3 Anopheles species were found in municipalities with high API (15–88 cases/1000 inhabitants): An. albimanus B, Anopheles calderoni and An. neivai s.l.ConclusionsIn the highest malaria areas of Colombia, 13 Anopheles species and four new lineages were found, which highlights the need for updating the species distribution. A DNA barcode analysis allowed the taxonomic identification to be refined, particularly for species complexes, and to improve the further understanding of their relation with malaria transmission.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1421-4) contains supplementary material, which is available to authorized users.

Highlights

A proper identification of malaria vectors is essential for any attempt to control this disease
The identity percent with sequences deposited in GenBank and Boldsystems databases was used as an initial approach for Anopheles species confirmation
The results are shown in the Additional file 1b. These results indicate that the sequences of species identified using morphological characters as An. albimanus from the Northwest showed a high percentage of identity (99 %) with sequences of An. albimanus from the Northern region of Colombia; in contrast, the sequences from the South Pacific coast presented a lower identity percentage (96– 97 %) with the same sequences deposited in GenBank

Summary

Introduction

A proper identification of malaria vectors is essential for any attempt to control this disease. The last review of the geographical distribution of Anopheles species in Colombia was published over 4 years ago and mentioned the presence of 40–47 Anopheles species including those belonging to species complexes [4]. A clear example is the recent analysis, based on the sequencing of the mitochondrial DNA marker, Cytochrome c Oxidase I (COI); which showed the presence of two species of the Anopheles (Nyssorhynchus) albitarsis complex in Colombia: An. Based on sequences of molecular markers, COI, and internal transcribed spacer 2 (ITS 2), analysis showed that there are three species of the complex oswaldoi-konderi in Colombia: Anopheles (Nys.) oswaldoi A in department of Amazonas; An. (Nys.) oswaldoi B in departments of Antioquia, Caqueta, Meta, Norte de Santander and Putumayo; and Anopheles sp. There are still gaps in knowledge about the distribution of Anopheles mosquitoes in Colombia, as well as the presence of Anopheles species of other species complexes [8]

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Conclusion