A survey of dengue fever vectors in Menglian and Lancang counties,Myanmar border

Objective To investigate the species composition,ecological habitats and the natural infection of the dengue vectors in Menglian and Lancang counties bordered with Myanmar in Yunnan province,so as to provide evidence for the prevention and control of dengue fever.Methods Three villages in Menglian and Lancang counties were selected as surveillance sites.Adult mosquitoes were captured by human-landing catches and Aedes mosquito larvae were collected from various types of indoor and outdoor water containers in the three surveillance sites.Dengue virus in mosquitoes was detected by RT-PCR.Results A total of 3436 individual adult female mosquitoes of 22 species from 8 subgenus in 6 genus were collected from three sites in Menglian and Lancang counties from June to October,2010.Aedes albopictus was the predominant species in three sites,accounting for 33.82% of all captured mosquitoes.No Ae.aegypti mosquitoes were found in these field sites.The average house index(HI),container index(CI),breteau index(BI),and thousand-person index of Ae.albopictus was 19.3,5.84,30.3,and 68.5 respectively.The dominant Ae.albopictus breeding environments were thick bamboo tubes,amphora,and used tires,accounting for 34.1%,27.5% and 17.6%,of positive water containers,respectively.The average population density of Ae.albopictus adults was 8.98 per person per hour.The density peaked in July and August.Dengue virus was not identified by RT-PCR from 29 batches of Ae.albopictus.Conclusion Local dengue fever surveillance should be strengthened due to high vector density and wide distribution of Ae.albopictus in these areas.