Development of molecular assays to detect target-site mechanisms associated with insecticide resistance in malaria vectors from Latin America

• Published in: Malaria Journal
• Main Authors: Juan C. Lol, David Castañeda, Lucy Mackenzie-Impoinvil, Carla G. Romero, Audrey Lenhart, Norma R. Padilla
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2019
• Subjects: Anopheles albimanus; Anopheles darlingi; Anopheles pseudopunctipennis; Anopheles vestitipennis; Insecticide resistance; Voltage-gated sodium channel gene; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-019-2834-7; https://doaj.org/article/f58f5848dd484909a9ccae39eb08b28a

Abstract Background Malaria remains an important public health problem in Latin America, and the development of insecticide resistance in malaria vectors poses a major threat to malaria elimination efforts. Monitoring of insecticide susceptibility and the determination of the mechanisms involved in insecticide resistance are needed to effectively guide the deployment of appropriate vector control measures. Here, molecular assays have been developed to screen for mutations associated with insecticide resistance on the voltage-gated sodium channel (VGSC) and acetylcholinesterase-1 (Ace-1) genes in four malaria vectors from Latin America. Methods Degenerate primers were designed to amplify a partial fragment on the VGSC and Ace-1 genes. Wild-caught individuals for Anopheles albimanus (also historical samples and individuals from a laboratory strain), Anopheles darlingi, Anopheles vestitipennis and Anopheles pseudopunctipennis were used to optimize the PCR assays. All samples were sequenced to validate the PCR results and DNA alignments were constructed for each gene using the unique haplotypes observed. Results Primers designed successfully amplified the VGSC gene in An. albimanus, An. darlingi, An. vestitipennis and An. pseudopunctipennis, and the Ace-1 gene in both An. albimanus and An. darlingi. DNA sequencing revealed that compared with Anopheles gambiae, there were a total of 29, 28, 21 and 24 single nucleotide polymorphisms (SNPs) on the VGSC gene for An. albimanus (308 bp), An. darlingi (311 bp), An. pseudopunctipennis (263 bp) and An. vestitipennis (254 bp), respectively. On the 459 bp fragment of the Ace-1 gene, a total of 70 SNPs were detected in An. darlingi and 59 SNPs were detected in An. albimanus compared with An. gambiae. The SNPs detected on the VGSC gene were all synonymous. On the Ace-1 gene, non-synonymous substitutions were identified on three different codons. All species showed the homozygous wild-type kdr allele (coding for leucine) at codon 995 (formerly reported as codon 1014) on the VGSC ...