河南省中华按蚊抗药性及其与kdr突变关联性的初步研究

Study on insecticide resistance of Anopheles sinensis from Henan Province and the association with the kdr mutation

目的了解河南省主要传疟媒介中华按蚊对拟除虫菊酯类杀虫剂的抗药性及其与击倒抗性基因型的关联性。方法2009年以区分剂量法调查河南省桐柏、淮滨和永城3地中华按蚊对溴氰菊酯和氟氯氰菊酯的抗药性，并抽取部分样本进行了kdr基因序列检测。x^2检验判断其抗药性与kdr基因突变的关联性。结果河南省3县（市）中华按蚊溴氰菊酯和氟氯氰菊酯的区分剂量死亡率均〈95％，其中淮滨地区中华按蚊对溴氰菊酯的死亡率及永城地区中华按蚊对溴氰菊酯和氟氯氰菊酯的死亡率均〈80％，为抗性群体；其余为初步抗性群体。溴氰菊酯（x^2=2．955，P〉0．05）和氟氯氰菊酯（x^2=0．000，P〉0．05）抗药性与kdr突变均无关联。结论kdr基因突变并不能直接引起中华按蚊对拟除虫菊酯类杀虫剂的抗性，具体的抗药性机制有待进一步研究。

Objective To investigate the pyrethroid resistance in the malarial vector Anopheles sinensis and the association with the kdr mutation. Methods The insecticide impregnated papers contact method recommended by WHO was used to observe the knockdown rate and the mortality of Anopheles, and the Leu-Phe mutation in the sodium channel gene was detected by polymerase chain reaction and sequencing. Results Insecticide susceptibility bioassay results showed that the mortalities of Anopheles sinensis from all three localities were lower than 95% on both deltamethrin and cyfluthrin. The Anopheles sinensis had resistance to dehamethrin in Huaibin County and to dehamethrin and cyfluthrin in Yongcheng City. The mortality of Anopheles sinensis from Huaibin County tested by cyfluthrin and from Tongbai County tested by deltamethrin and cyfluthrin were between 80% -95%. There is no relationship between kdr mutation and the resistance phenotype of Anopheles sinensis to dehamethrin and x1^2 cyfluthnn（x1^2 =2. 955,x2^2 =0. 000,P 〉0. 05）. Conclusion The kdr mutation apparently does not play an important role in the pyrethroid resistance to An. sinensis, further studies are needed to determine the precise mechanisms involved .