Human biting activity, spatial–temporal distribution and malaria vector role of Anopheles calderoni in the southwest of Colombia

Abstract

BackgroundAnopheles calderoni was first recognized in Colombia in 2010 as this species had been misidentified as Anopheles punctimacula due to morphological similarities. An. calderoni is considered a malaria vector in Peru and has been found naturally infected with Plasmodium falciparum in Colombia. However, its biting behaviour, population dynamics and epidemiological importance have not been well described for Colombia.MethodsTo assess the contribution of An. calderoni to malaria transmission and its human biting behaviour and spatial/temporal distribution in the southwest of Colombia, human landing catches (HLC) and larval collections were carried out in a cross-sectional, entomological study in 22 localities between 2011 and 2012, and a longitudinal study was performed in the Boca de Prieta locality in Olaya Herrera municipality between July 2012 and June 2013. All mosquitoes determined as An. calderoni were tested by ELISA to establish infection with Plasmodium spp.ResultsLarvae of An. calderoni were found in four localities in 12 out of 244 breeding sites inspected. An. calderoni adults were collected in 14 out of 22 localities during the cross-sectional study and represented 41.3% (459 of 1,111) of the collected adult specimens. Other species found were Anopheles albimanus (54.7%), Anopheles apicimacula (2.1%), Anopheles neivai (1.7%), and Anopheles argyritarsis (0.2%). In the localities that reported the highest malaria Annual Parasite Index (>10/1,000 inhabitants) during the year of sampling, An. calderoni was the predominant species (>90% of the specimens collected). In the longitudinal study, 1,528 An. calderoni were collected by HLC with highest biting rates in February, May and June 2013, periods of high precipitation. In general, the species showed a preference to bite outdoors (p < 0.001). In Boca de Prieta, two specimens of An. calderoni were ELISA positive for Plasmodium circumsporozoite protein: one for P. falciparum and one for Plasmodium vivax VK-210. This represents an overall sporozoite rate of 0.1% and an annual entomological inoculation rate of 2.84 infective bites/human/year.ConclusionsThis study shows that An. calderoni is a primary malaria vector in the southwest of Colombia. Its observed preference for outdoor biting is a major challenge for malaria control.

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

“…might be contributing to malaria transmission in regions where this species is present (6,11,12). However, as the infected specimen on this study was recollected in livestock corrals and the Plasmodium spp.…”

“…However, species composition and frequencies vary among sampling sites and seasons, rendering constant monitoring of these parameters essential (7,12). In this study we analyzed species abundance and composition, biting preferences and natural infection with Plasmodium of Anopheles mosquitoes from nine locations of two malaria-endemic regions of Colombia.…”

“…Likewise, recent studies carried out in some malaria-endemic regions of Colombia have shown additional Anopheles species naturally infected with Plasmodium spp., such as A. benarrochi B, which was found infected with the two strains of P. vivax (8); A. triannulatus s.l. and A. calderoni with P. vivax and P. falciparum (9)(10)(11)(12), suggesting a possible role of these anopheline mosquitoes in the transmission of the malaria parasite.…”

“…In addition, permanent changes in environmental and climatic conditions in malaria endemic areas (6,12) highlight the importance of frequently monitoring parameters such as abundance, composition and natural infection of the Anopheles species, which would contribute to improving local vector control strategies.…”

Quantifying Seasonal and Diel Variation in Anopheline and Culex Human Biting Rates in Southern Ecuador

“…Despite being a competent vector of Plasmodium spp., An. calderoni was only recently confirmed in several Latin American countries, including Ecuador, due to the systematic misclassification of the species [52,53]. The potential for misidentification of these taxa on surveys may obscure true species-level patterns in biting activity.…”