Open AccessInsecticide resistance in Culex quinquefasciatus mosquitoes after the introduction of insecticide‐treated bed nets in Macha, Zambia
Author(s) -
Norris Laura C.,
Norris Douglas E.
Publication year - 2011
Publication title -
journal of vector ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.688
H-Index - 51
eISSN - 1948-7134
pISSN - 1081-1710
DOI - 10.1111/j.1948-7134.2011.00182.x
Subject(s) - culex quinquefasciatus , biology , deltamethrin , knockdown resistance , malathion , insecticide resistance , population , bioassay , toxicology , culex , pesticide resistance , veterinary medicine , pesticide , genetics , larva , ecology , environmental health , cyfluthrin , aedes aegypti , medicine
Culex quinquefasciatus , an arboviral and filarial vector, is present in high numbers throughout sub‐Saharan Africa, and insecticide‐resistant populations have been reported worldwide. In order to determine the insecticide resistance status of Cx. quinquefasciatus in Macha, Zambia, adult mosquitoes reared from eggs collected from oviposition traps were tested by bioassay. High levels of resistance to DDT, pyrethroids, malathion, and deltamethrin‐treated net material were detected, and molecular assays revealed that the knockdown resistance ( kdr ) allele was frequent in the Cx. quinquefasciatus population, with 7.0% homozygous for the kdr L1014 allele and 38.5% heterozygous (0.263 kdr frequency). The kdr frequency was significantly higher in mosquitoes that had successfully fed on human hosts, and screening archived specimens revealed that kdr was present at lower frequency prior to the introduction of ITNs, indicating that ITNs might be a selective force in this population. Additionally, metabolic detoxification enzyme activity assays showed upregulated glutathione S‐transferases, α‐esterases, and β‐esterases. Continued monitoring and assessment of the Cx. quinquefasciatus population is necessary to determine levels of resistance.