Teng Hwa-jen, an associate research fellow at the NIPM, notes that a survey of carrier mosquitoes in Chungho by the government's "dengue fever prevention task force" discovered that, after two years of outdoor spraying of pesticides to kill the insects, the concentration of carrier mosquitoes had returned to its original level.
預防醫學研究所病媒昆蟲組副研究員鄧華真也指出，登革熱防治小組在中和地區做的病媒蚊調查發現，在戶外噴灑藥劑殺蟲兩年後，病媒蚊的密度又回到原點。