Geographic distribution of wolbachial infections in mosquitoes from Thailand.

Members of the genus Wolbachia are inherited intracellular bacterial endosymbionts that infect a diverse range of arthropods. Here I report the results of a survey of these endosymbionts in different mosquito species from six geographic regions of Northern, Northeastern, Western, Central, Eastern and Southern Thailand. Using gene amplification assays with wsp and groE gene primers, wolbachiae were detected in 999 mosquitoes representing 28 species of 1622 specimens collected representing 74 species of wild-caught mosquitoes from all regions of Thailand. Results using wsp primers were similar to those using groE primers in all cases. Wolbachiae had not been reported previously from five of the species tested, namely, Aedes lineatopennis, Aedes vexans, Aedes vittatus, Culex pallidothorax and Culex whitmorei. Infections were found in all major disease vector genera except Anopheles. These results indicate that wolbachial infections are distributed throughout many mosquito species in Thailand.