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Mutaciones de resistencia Knockdown ( kdr ) y susceptibilidad a los insecticidas DDT y piretroides en Anopheles gambiae de Guinea Ecuatorial
Author(s) -
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.
Publication year - 2008
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.2008.02010.x
Subject(s) - knockdown resistance , insecticide resistance , anopheles gambiae , biology , gene knockdown , malaria , toxicology , genetics , pesticide , permethrin , immunology , gene , cyfluthrin , ecology
Summary Objectives 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. Methods 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. Results 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%. Conclusion 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.