Evaluation of Performance of Space Sprayer for Dengue Vector Control

Wei-Tai Hsia¹,Ho-Sheng Wu¹,Lili-Lee¹,Shiou-Pin Lin¹,Fang-Ying Shen²

2013 Vol.29 NO.16

Correspondence Author： Wei-Tai Hsia

Abstract：

       With high temperature, humidity and population density, Taiwan has epidemics of dengue every year. Dengue is not only an environmental disease but also an important vector-borne disease around the world. An epidemic of vector-borne disease needs the co-existence of pathogen, vulnerable host and vector. Since there are no effective medicine and protective vaccine available for dengue currently, we could only suppress the mosquito population density by carry out Integrate Vector Control which is Source Reduction first and spraying insecticides subsidiary later, ordinarily. While in dengue outbreak, Taiwan local government will conduct emergency spray operation immediately to control the epidemic in a short time for resident health concern.

       A successful chemical control program is composed of three factors: efficient sprayer, effective insecticide and skillful technician. Fog and Ultra-Low Volume (ULV) sprayers are applied to do Space Spray usually. This study selected several Fogs (fifteen models with thirty kinds of spraying combinations) and ULVs (fourteen models with forty five kinds of spraying combinations.) which often used to do Space Spray in southern Taiwan, and examined their efficacy by nebulization efficiency and flow rate stability. The results could provide epidemic prevention technicians to conduct precise spraying and raise the efficiency of chemical control.

       Results showed that there were 50% of ULV models (7/14) had unstable flow rate, the ratio was higher than Fog models (20%, 3/15). The droplets size of most of the ULV models was fit in the Space Spray request. Only 7.1% of ULVs models (1/14) had over large droplets and the ratio was lower than Fog models (33.3%, 5/15). Generally, Fogs had relatively stable flow rate and poor nebulization efficiency than ULV. Stability of flow rate may relate to the conformation of sprayer and the nebulized efficiency has close relationships with their operate principles or types of nozzle. The efficacy of sprayer seems to have nothing to do with its power but is associated with the quality control of the manufactory where it was made from.