Frequencies of voltage-gated sodium channels kdr mutations in Culex quinquefasciatus and Aedes albopictus (Diptera: Culicidae) of northeastern México

Introduction: A mechanism is widely studied kdr resistance given by knockdown or nonsynonymous mutations in the gene encoding a sodium channel voltage, resulting in the effect of reducing the sensitivity of the central nervous system of the insect to pyrethroid insecticides that have been widely used in Mexico within the mosquito control campaigns vectors. In Mexico there are no population control campaigns for Culex quinquefasciatus and Aedes albopictus mosquitoes more but these are affected indirectly with insecticides used to control Aedes aegypti vector of dengue viruses.

Methods: For PCR (using the oligos) was amplified from genomic DNA segment encoding the segment intramembrenal 6 Na + channel A. albopictus. The extracted DNA specimens came from 8 different towns in the state of Nuevo Leon, Mexico, while for Cx. quinquefasciatus populations were analyzed 13. The amplified products were cloned into the pTOPO vector XL 3.5. subsequently, the positive clones were sequenced with M13 oligos. The chromatograms were analyzed and interpreted in the bioinformatics Genestudio program.

Results: From the state of Nuevo Leon, a total of 116 mosquitoes were analyzed for Kdr mutation L1014F in 2008 determining frequencies between 0.066 to 0.60 (Lampazos-Monterrey), between 2012-13, 142 samples were analyzed and identified frequencies between 0.045 and 0.636 (Anahuac 12 Monterrey 12 and San Nicolas 13). In the state of Coahuila were determined frequencies between 0.033-0.124 (Monclova 12 Muzquiz 13) in 84 mosquitoes tested. In 2008, collections were made only in the State of Nuevo Leon with four populations, which were collected four years later, population of Anahuac 2008 (0.116) and 2012 (0.045), there was a slight decrease in the frequency of L1014F mutation, this may indicate that by the year 2012 there was a greater presence of heterozygous organisms because the FIS reported was less than zero (-0.041). Were identified by nucleotide sequencing 4 different variables of varying types of sequences from one another specifically in introns flanking the exon been linked to resistance Ae. albopictus to pyrethroids.

Conclusions and discussion: In addition, nucleotide sequencing resulted a powerful tool to identify genomic variables in A. albopictus. 4 genotypes new intronic of a Na + channel A. albopictus be associated with resistance phenotypes such as insecticides, survival, rapid metabolism, etc.. In recent days the importance of introns to increase the function inferred methylation levels and / or microRNAs. Cx quinquefasciatus results revealed an increase in the L1024F mutation in populations of 2012 and 13 with respect to the populations analyzed in 2008 for the state of Nuevo Leon. This may be due to Culex populations are being selected indirectly by mosquito control campaigns Ae. aegypti in this state.