Survey of Dengue Fever Vector Density before and after Insecticide Spraying

Chih-Yuan Wang1, Chao Lin1, Ying-Feng Ge2, Hsin-Fan Chien2, Chein-Sheng Lin3,Chin-Shyan Wang3, Shu-Wan Jian1, Yu-Hsin Chen2,Yu-Zhu Wang2, Hwa-Jen Teng1

2011 Vol.27 NO.19

Correspondence Author: Hwa-Jen Teng


Because of the emergency dengue fever mosquito control and the low temperature and dry condition in winter, dengue viruses usually can not overwinter in Taiwan. In 2010, Kaohsiung City Government launched a control program to prevent these circulating dengue virus strains sustaining through the winter in Kaohsiung City. This study conducted the adult vector density surveys before and after insecticide application within a 100-meter (in radius) area around the house of a confirmed dengue fever patient in Kaohsiung City. A comparative study was also conducted in Fengshan City, Kaohsiung County. Before insecticide spraying, the adult mosquito index was 0.77 in Cianjhen District, Kaohsiung City, and was reduced to 0.23 after insecticide spraying (reduction rate=69.6%). The adult vector index in Fengshan City, Kaohsiung County, was 0.33 and 0.10 before and after the insecticide spraying, respectively (reduction rate=70%). Forty-three female and 12 male Aedes aegypti were collected in these 2 study areas. The main resting sites of these female mosquitoes included kitchen (35.5%), bedroom (32.3%), living room (19.4%), bathroom (6.5%), basement (3.2%), and storage room (3.2%). This result indicated that single insecticide spraying might reach 70% reduction rate and, thus, should combine with the second insecticide application, environmental factors, or other control measures to interrupt the transmission cycle.