Natural Malaria Infection in Anopheline Vectors and Their Incrimination in Local Malaria Transmission in Darién, Panama

Abstract

BackgroundMore than 85% of the malaria cases in Panama occur in characteristically poor, rural and indigenous regions like Darien Province. Vector diversity, vector infection rate and spatial distribution are important entomological parameters of malaria transmission dynamics. Their understanding is crucial for the development of effective disease control strategies. The objective of this study was to determine the composition of Anopheles species, their natural infection rate and their geographic distribution to better understand the malaria transmission dynamics in Darién, Panama.MethodsAnopheline mosquitoes were captured during the rainy and dry season of 2016. We selected five communities where adult anophelines were collected using CDC light-traps, and through protective human-baited traps. Detection of natural infection and Plasmodium genotype in collected mosquitoes were detected via nested PCR through the amplification of Plasmodium 18s rRNA and the circumsporozoite protein gene, respectively.ResultsA total of 1,063 mosquitoes were collected, and nine Anopheline species were identified, with the predominant species being: An. (Nys.) darlingi (45.0%) and An. (Nys.) albimanus (42.6%). Among these mosquitoes, An. (Nys.) albimanus has historically presented an elevated frequency and abundance in all Panamanian regions. Natural infection with P. vivax was detected in a mosquito pool from the community Pueblo Tortuga (0.6%), three mosquito pools from Marraganti (1.7%), two pools from Bajo Chiquito (1.1%) and three pools from Alto Playona (1.7%). For An. (Nys.) darlingi mosquitoes, we detected seven positive pools from the community Bajo Chiquito (4.0%), two pools from Marraganti (1.1%) and two pools from Alto Playona (1.1%). This study was able to detect the P. vivax allelic variant VK210 in infected mosquitoes.ConclusionThe results from this study provide new information on the transmission dynamics associated with anopheline vectors in the Darién region. This is the first report of natural P. vivax infection in An. (Nys.) darlingi and its incrimination as a potential malaria vector in Panama. Additional studies are necessary to expand our knowledge and determine crucial parameters in malaria transmission in Darién, which in turn will aid the National Malaria Program in attaining an adequate malaria control strategy towards malaria elimination.