Larval habitat characteristics of the main malaria vectors in the most endemic regions of Colombia: potential implications for larval control

Abstract

BackgroundMalaria incidence has recently decreased globally and, as malaria elimination is envisioned as a possibility by the health authorities, guidance is needed to strengthen malaria control strategies. Larval source treatment, which could complement routine vector control strategies, requires knowledge regarding the Anopheles larval habitats.MethodsA cross-sectional study was conducted in three of the most malaria-endemic regions in Colombia. A total of 1116 potential larval habitats in 70 villages were sampled in three states located in western Colombia: Cordoba, Valle del Cauca and Nariño.ResultsOverall, 17.5 % (195) of the potential larval habitats were found positive for different Anopheles species. A total of 1683 larvae were identified belonging to seven species: Anophelesalbimanus, Anopheles calderoni, Anophelesdarlingi, Anophelesneomaculipalpus, Anophelesnuneztovaris.l., Anophelespseudopunctipennis, and Anophelestriannulatus. The most widely distributed species was An. nuneztovari s.l., which was found mainly in human-made fishponds in Cordoba and temporary puddles in Valle del Cauca. Anophelesalbimanus and An. calderoni were associated with human-made wells or excavation sites in Nariño. Cordoba displayed the greatest Anopheles species diversity with a total of six species (Shannon diversity index H′: 1.063). Although Valle del Cauca had four species, one more than Nariño, the diversity was lower because only one species predominated, An. nuneztovari s.l. The larval habitats with the highest Shannon diversity index were lagoons (H′: 1.079) and fishponds (H′: 1.009) in Cordoba, excavation sites in Nariño (H′: 0.620) and puddles in Valle del Cauca (H′: 0.764).ConclusionsThis study provides important information regarding the larval habitats of the main malaria vectors in the most malaria-endemic regions of Colombia, which will be useful in guiding larval control operations.

Abundance, composition and natural infection of Anopheles mosquitoes from two malaria-endemic regions of Colombia

“…was the second most abundant species in the same municipality, but in a different location (6), and a study in the department of Córdoba where A. triannulatus s.l. and A. nuneztovari larvae were predominant (30). Additionally, most of the specimens were collected in livestock corrals (figure 2), which suggests a zoophilic biting preference, as formerly reported (5).…”

Downscaling incidence risk mapping for a Colombian malaria endemic region

“…Malaria is one of the most important problems of public health in Colombia, the country reported 17% of cases of the Americas in 2016 , and the disease remains a threat in areas where various human activities such as mining and coca‐cultivation have become prevalent . Particularly, the Urabá‐Bajo Cauca and Alto Sinú (UCS) region has historically reported the highest numbers of malaria cases in the country , but currently, is second in number after the Pacific region with 16.600 cases .…”

Distribución y parámetros entomológicos de Anopheles (Anopheles) calderoni (Diptera: Culicidae) de Colombia

“…Se estimó que una persona puede recibir 3.1 picaduras infectivas al año. Por su comportamiento antropofílico y el hallazgo de su infección natural por el parásito, se considera que A. calderoni es un vector potencial de malaria a nivel local, específicamente en el sureste del país (Conde et al, 2015;Naranjo-Díaz et al, 2014). Aunque la tasa de infección para A. calderoni reportada en este estudio es de 0.17%, es menor que la reportada para Perú (0.26%) (Cruz et al, 2004), pero es mayor a las reportadas para vectores primarios como A. nuneztovari (0.101%) y A. darlingi (0.087%) (Naranjo-Díaz et al, 2013).…”

“…Trabajos posteriores con especímenes recolectados en campo reportan a A. calderoni en varias localidades del occidente colombiano (Gómez et al, 2015;Orjuela et al, 2015;Rodríguez-Zabala et al, 2016). Las larvas de A. calderoni se detectan tanto en criaderos permanentes como en temporales, en criaderos artificiales de uso doméstico, en excavaciones, lagunas, estanques de peces, zanjas, arroyos y cultivos de palma (Conde et al, 2015;Naranjo-Díaz et al, 2014;Orjuela et al, 2015). Por ello, se supone que podría tener una distribución más amplia de la conocida actualmente.…”