Moreno M, Vicente J L, Cano J, Berzosa P J, de Lucio A, Nzambo S, Bobuakasi L, Buatiche J N, Ondo M, Micha F, Do Rosario V E, Pinto J, Benito A
Centro Nacional de Medicina Tropical. Instituto de Salud Carlos III, Madrid, Spain.
Trop Med Int Health. 2008 Mar;13(3):430-3. doi: 10.1111/j.1365-3156.2008.02010.x.
To determine the frequency of knockdown resistance (kdr) mutations in the malaria vector Anopheles gambiae s.s. from continental Equatorial Guinea; and to relate kdr genotypes with susceptibility to DDT and pyrethroid insecticides in this vector.
Female mosquitoes were collected in two villages, Miyobo and Ngonamanga, of mainland Equatorial Guinea. Insecticide susceptibility tests were performed following WHO procedures. Anopheles gambiae complex specimens were identified to species and molecular form by PCR. Genotyping of the kdr locus was performed by allele-specific PCR and direct sequencing in a subset of samples.
Both M and S molecular forms of A. gambiae were found in Ngonamanga whereas only the S-form was identified in Miyobo. The two kdr mutations were detected in S-form samples of both villages, with a higher frequency of the kdr-e (Leu-1014-Ser) allele (Miyobo: 16%; Ngonamanga: 40%). The kdr-w (Leu-1014-Phe) mutation was also detected in 3% of the M-form. All individuals tested for pyrethroids were susceptible. A mortality rate of 86% was obtained for DDT. An overall kdr allele frequency (i.e. kdr-e + kdr-w) of 22% was detected in DDT resistant individuals, whereas susceptible individuals had a kdr frequency of 6%.
The co-occurrence of both kdr mutations and reduced susceptibility to DDT found in A. gambiae highlights the importance of implementing efficient surveillance of insecticide resistance in Equatorial Guinea.
确定来自赤道几内亚大陆的冈比亚按蚊（Anopheles gambiae s.s.）中击倒抗性（kdr）突变的频率；并将kdr基因型与该媒介对滴滴涕和拟除虫菊酯类杀虫剂的敏感性相关联。
在赤道几内亚大陆的两个村庄，米约博（Miyobo）和恩戈纳曼加（Ngonamanga）采集雌性蚊子。按照世界卫生组织的程序进行杀虫剂敏感性测试。通过聚合酶链反应（PCR）将冈比亚按蚊复合体标本鉴定到物种和分子型。在一部分样本中通过等位基因特异性PCR和直接测序对kdr位点进行基因分型。
在恩戈纳曼加发现了冈比亚按蚊的M型和S型两种分子型，而在米约博仅鉴定出了S型。在两个村庄的S型样本中均检测到了两种kdr突变，kdr-e（亮氨酸-1014-丝氨酸）等位基因的频率较高（米约博：16%；恩戈纳曼加：40%）。在3%的M型中也检测到了kdr-w（亮氨酸-1014-苯丙氨酸）突变。所有接受拟除虫菊酯测试的个体均敏感。滴滴涕的死亡率为86%。在对滴滴涕有抗性的个体中检测到的总体kdr等位基因频率（即kdr-e + kdr-w）为22%，而敏感个体的kdr频率为6%。
在冈比亚按蚊中发现的kdr突变与对滴滴涕敏感性降低的共同出现凸显了在赤道几内亚实施高效杀虫剂抗性监测的重要性。
