Detection of the V1016G mutation of the voltage-gated sodium channel (VGSC) gene in aedes aegypti from Cavite and Laguna, Philippines

Date of Publication

2024

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Biology major in Medical Biology

Subject Categories

Biology

College

College of Science

Department/Unit

Biology

Thesis Advisor

Thaddeus M. Carvajal

Defense Panel Member

Frances C. Recuenco
Paolo Ramon D.C. Pacheco
Shad Natthew S. Arce

Abstract (English)

Aedes aegypti, a principal vector for viral diseases such as dengue, poses a growing threat and a significant public health concern in the Philippines. The country witnessed a dramatic surge in dengue cases with significant outbreaks reported across regions. Despite collaborative interventions, the effective management of Ae. aegypti has remained elusive. Chemical control strategies, particularly the use of pyrethroids, have shown efficacy in vector control. However, the continuous application of insecticides has led to the emergence of resistance mechanisms in mosquito populations, such as knockdown resistance (kdr). This preliminary report marks the first comprehensive investigation in the Philippines aimed at addressing the current lack of information regarding the insecticide resistance of Ae. aegypti populations through a molecular approach. The primary objective is to genotypically characterize the insecticide resistance detected in these populations focusing on the collection of Ae. aegypti populations from multiple locations, including DLSU Laguna Campus, Cavite, and Sta. Rosa, Laguna. A total of 70 samples were identified and tested for resistance using the allele-specific polymerase chain reaction (AS-PCR) protocol of Sene et al. (2021) for the specific mutation kdr V1016, with some modifications for PCR optimization. The genotyping analysis revealed that samples from DLSU Laguna Campus were all homozygous wild-type (V/V), whereas samples from other locations exhibited varying genotypes. In Sta. Rosa, Laguna, the majority were homozygous wild-type (72.7%) with a minority being heterozygous (V/G, 27.3%). In Cavite, there was an equal distribution of homozygous wild-type and heterozygous (48% each), with a small percentage of homozygous mutants (G/G, 4%). Overall, these findings underscore the presence of the V1016G mutation in Ae. aegypti populations from Cavite and Laguna, Philippines. These genetic variations may arise from local mutation due to insecticide exposure, dispersal of resistant mosquitoes, or human-mediated transport within the country. This initial report of the V1016G mutation highlights significant implications for managing Ae. aegypti and suggests that resistance to pyrethroids may be evolving in local populations. The findings also emphasize the potential role of urbanization and frequent insecticide use in the development and spread of resistance. Further research with an increased number of samples and examination of the insecticide susceptibility status based on the CDC bottle-assay is recommended for more understanding of the mechanisms underlying insecticide resistance, providing critical insights for the development of effective control measures.

Abstract Format

html

Abstract (Filipino)

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Abstract Format

html

Language

English

Format

Electronic

Keywords

Aedes aegypti--Philippines--Cavite; Aedes aegypti--Philippines--Laguna; Insecticide resistance

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Embargo Period

5-3-2024

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