Kdr-based insecticide resistance in Anopheles gambiae s.s populations in

<p>Abstract</p> <p>Background</p> <p>The spread of insecticide resistance in the malaria mosquito, <it>Anopheles gambiae </it>is a serious threat for current vector control strategies which rely on the use of insecticides. Two mutations at position 1014 of the S₆transmembrane segment of domain II in the voltage gated sodium channel, known as <it>kdr </it>(<it>knockdown resistance</it>) mutations leading to a change of a Leucine to a Phenylalanine (L1014F) or to a Serine (L1014S) confer resistance to DDT and pyrethroid insecticides in the insect. This paper presents the current distribution of the <it>kdr </it>alleles in wild <it>Anopheles gambiae </it>populations in Cameroon.</p> <p>Results</p> <p>A total of 1,405 anopheline mosquitoes were collected from 21 localities throughout Cameroon and identified as <it>An. gambiae </it>(N = 1,248; 88.8%), <it>An. arabiensis </it>(N = 120; 8.5%) and <it>An. melas </it>(N = 37; 2.6%). Both <it>kdr </it>alleles 1014F and 1014S were identified in the M and S molecular forms of <it>An. gambiae </it>s.s. The frequency of the 1014F allele ranged from 1.7 to 18% in the M-form, and from 2 to 90% in the S-form. The 1014S allele ranged from 3-15% in the S-form and in the M-form its value was below 3%. Some specimens were found to carry both resistant <it>kdr </it>alleles.</p> <p>Conclusion</p> <p>This study provides an updated distribution map of the <it>kdr </it>alleles in wild <it>An. gambiae </it>populations in Cameroon. The co-occurrence of both alleles in malaria mosquito vectors in diverse ecological zones of the country may be critical for the planning and implementation of malaria vector control interventions based on IRS and ITNs, as currently ongoing in Cameroon.</p