A descriptive assessment of mitochondrial COI genetic diversity and dengue and chikungunya RNA detection in Aedes aegypti across eight provinces in Thailand.

BACKGROUND

Aedes aegypti is the principal vector of several medically important arboviruses, including dengue virus (DENV) and chikungunya virus (CHIKV), both of which remain endemic in Thailand. However, studies on arbovirus surveillance and mitochondrial genetic diversity of Ae. aegypti populations across broad geographic scales remain limited. This study aimed to assess the detection of DENV and CHIKV and characterize the mitochondrial genetic diversity of Ae. aegypti across multiple regions of Thailand.

METHODS

A total of 303 adult Ae. aegypti mosquitoes collected from eight provinces across five geographic regions of Thailand were screened for DENV and CHIKV RNA. Mitochondrial cytochrome c oxidase subunit I (COI) genetic diversity was assessed using haplotype network analysis and analysis of molecular variance (AMOVA).

RESULTS

CHIKV RNA was detected in 51 mosquitoes (16.8%) from four provinces, with the highest detection rates observed in Prachuap Khiri Khan and Bangkok. DENV RNA was not detected in any sample. COI analysis revealed moderate to high mitochondrial haplotype diversity and geographic variation in haplotype distribution among populations. Both widely shared and province-specific haplotypes were identified. AMOVA indicated that most genetic variation occurred within populations (93.19%), with significant genetic differentiation among populations (ΦST = 0.068, P < 0.001).

CONCLUSIONS

CHIKV RNA was detected in Ae. aegypti populations from multiple regions of Thailand, whereas DENV RNA was not detected. Mitochondrial COI analysis revealed substantial haplotype diversity and geographic variation among populations. These findings contribute to current knowledge of arbovirus occurrence and mosquito genetic diversity in Thailand and provide a foundation for future vector surveillance studies.