Genetic variability of the Aedes aegypti (Diptera: Culicidae) mosquito in El Salvador, vector of dengue, yellow fever, chikungunya and Zika

Abstract

BackgroundAedes aegypti is associated with dengue, yellow fever, chikungunya and Zika viruses. This vector is widespread in tropical and subtropical areas, and can also occur in temperate areas at higher latitudes. The geographical distribution of Ae. aegypti continues to spread due to human activities. This is the first study to examine the population genetic structure of this insect in El Salvador, Central America.MethodsAedes aegypti larvae were collected from six geographical regions of El Salvador: Sonsonate, San Salvador, Chalatenango, Usulután, San Miguel and Morazán. Larvae were raised into adults, identified and preserved. Two molecular markers, amplified fragment length polymorphism (AFLP) genotyping and mitochondrial DNA (mtDNA) cytochrome c oxidase subunit 1 (cox1) sequencing, were used to investigate population genetic structure.ResultsStructure analysis found two genetically distinct populations; one occurs predominantly in the north and west, and a mix of two populations occurs in the southeast of the country. Genetic distances ranged from 0.028 (2.8%) to 0.091 (9%), and an AMOVA analysis found 11% variation between populations. Mitochondrial DNA cox1 sequences produced a haplotype network which consisted of 3 haplogroups and 10 haplotypes. Haplogroup 1 had low haplotype and nucleotide diversity and was found in all six regions. Haplogroups 2 and 3 had higher haplotype and nucleotide diversity, and were less abundant; haplogroup 3 was found in only 3 of the six regions studied. Bottleneck tests were significant, suggesting that populations had undergone a recent bottleneck. A maximum likelihood tree, which combined samples from this study with available sequences in GenBank, suggested that two genetically divergent lineages had been introduced.ConclusionsRelatively high genetic diversity was found in Ae. aegypti in El Salvador. The mtDNA sequences clustered into two lineages, as found in previous studies. Samples in El Salvador may be introduced from regions in North and South America where past eradication was not complete. Future study of genotypes in surrounding countries would provide a more complete picture of the movement and potential source of introductions of this vector. The distribution of the lineages and haplogroups may further our understanding of the epidemiology of Ae. aegypti associated vector borne diseases.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3226-5) contains supplementary material, which is available to authorized users.

Distinct haplotypes and free movement ofAedes aegyptiin Port Sudan, Sudan

“…The overall haplotype diversity detected in this study was similar to what could be found elsewhere (Calvez et al., 2016; Joyce, Torres, Torres, & Moreno, 2018; Liu et al., 2019). This could be attributed to the fact that these mosquitoes are migrating a lot.…”

Wolbachia in mosquitoes from the Central Valley of California, USA

“…aegypti to be evaluated for vector control applications [ 42 – 46 ]. Aedes aegypti is widespread in tropical and subtropical regions globally [ 47 , 48 ], and since its detection in California in 2011 it has become widespread in southern California and the Central Valley [ 49 , 50 ]. One example of where Wolbachia -infected Ae .…”

Identification of Aedes (Diptera: Culicidae) Species and Arboviruses Circulating in Arauca, Eastern Colombia

“…PCR reactions were performed in a final volume of 20 µL containing 10 µL qScript TM One-Step, Low ROX TM (Quantabio, Carlsbad, CA, United States), 10 µM of each primer and 5 µL of RNA. The primers LCO1490 (5 -GGT CAA ATC ATA AAG ATA TTG G-3) and HCO2198 (5 -TAA ACT TCA GGG TGA CCA AAA AAT CA-3 ) were also used (Joyce et al, 2018). The thermal profile consisted of the following: one cycle at 50 • C for reverse transcriptase activation for 10 min followed by initial denaturation at 95 • C for 1 min, 45 cycles of 94 • C for 10 s, 60 • C for 1 min and final extension at 72 • C for 10 min.…”

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