First Detection and Genetic Identification of Wolbachia Endosymbiont in Field-Caught Aedes aegypti (Diptera: Culicidae) Mosquitoes Collected from Southern Taiwan

The prevalence and genetic character of Wolbachia endosymbionts in field-collected Aedes aegypti mosquitoes were examined for the first time in Taiwan. A total of 665 Ae. aegypti were screened for Wolbachia infection using a PCR assay targeting the Wolbachia surface protein (wsp) gene. In general, the prevalence of Wolbachia infection was detected in 3.3% Ae. aegypti specimens (2.0% female and 5.2% male). Group-specific Wolbachia infection was detected with an infection rate of 1.8%, 0.8% and 0.8% in groups A, B and A&B, respectively. Genetic analysis demonstrated that all Wolbachia strains from Taiwan were phylogenetically affiliated with Wolbachia belonging to the supergroups A and B, with high sequence similarities of 99.4–100% and 99.2–100%, respectively. Phylogenetic relationships can be easily distinguished by maximum likelihood (ML) analysis and were congruent with the unweighted pair group with the arithmetic mean (UPGMA) method. The intra- and inter-group analysis of genetic distance (GD) values revealed a lower level within the Taiwan strains (GD < 0.006 for group A and GD < 0.008 for group B) and a higher level (GD > 0.498 for group A and GD > 0.286 for group B) as compared with other Wolbachia strains. Our results describe the first detection and molecular identification of Wolbachia endosymbiont in field-caught Ae. aegypti mosquitoes collected from Taiwan, and showed a low Wolbachia infection rate belonging to supergroups A and B in Ae. aegypti mosquitoes.