湖北省三县（市）媒介按蚊抗药性的现场调查

目的了解媒介按蚊对DDT和溴氰菊酯的抗药性，为制定防制策略提供科学依据。方法采用WHO成蚊滤纸接触法，观察蚊虫击倒率和死亡率，以Finney机率分析法进行对数-机率分析。结果湖北省京山县、安陆市和孝昌县媒介按蚊对DDT和溴氰菊酯区分剂量击倒率均〈20％，死亡率均〈50％，为高抗群体；对DDT的KT5。分别为1718．63、343．73和624．45min，具有很强的抗击倒力，其LG0均〉4％，与1996年调查结果一致；对溴氰菊酯的KT50分别为227．78、138．41和263．41min，比1996年分别提高34、20和44倍，其LT50为684．12min，比1998年提高了306倍。结论DDT停用多年后抗药性未明显下降，而溴氰菊酯的抗药性则呈几百倍的速度发展，可能成为拟除虫菊酯和DDT应用的最大障碍，应定期进行监测，及时采取有效措施。

The field investigation on the resistance of Anopheles in Jingshan,Anlu and Xiaochang of Hubei province

Objective To understand the resistance of Anopheles to DDT and Deltamethrin,and then provide scientific evidence for the establishment of prevention and control strategy.Methods Adult Anopheles filter contact method recommended by WHO was used to observe the knockdown rate and the mortality of Anopheles,and the relationship of logarithm-probability was analyzed with the method of Finney probability.Results The Anopheles had high resistance to DDT and deltamethrin in Jingshan county,Anlu city and Xiaochang county,and the knockdown rates of DDT and deltamethrin discrimination dosage to it were less than 20%,and their mortality were all less than 50%.The KT50 values of DDT were 1718.63,343.73 and 624.45 min respectively,which had higher anti-knockdown capability.The LC50 of DDT exceeded 4%,accordant with that in 1996.The KT50 of deltamethrin were 227.78,138.41 and 263.41 min respectively,which were 34,20,44 times than that in 1996,respectively.The LT50 was 684.12 min,which was 306 times than that in 1998.Conclusion The resistance did not decrease after the forbiddance of DDT for many years,however,the resistance to deltamethrin increases at the several hundred times speed,which could be the obstacle of pyrethroid and DDT application,so we should carry out regular monitoring and make effective measures timely.