Distribution of a Knockdown Resistance Mutation (L1014S) in Anopheles gambiae s.s. and Anopheles arabiensis in Western and Southern Kenya
Open Access
- 9 September 2011
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 6 (9), e24323
- https://doi.org/10.1371/journal.pone.0024323
Abstract
In Kenya, insecticide-treated mosquito nets (ITNs) distributed to pregnant women and children under 5 years old through various programs have resulted in a significant reduction in malaria deaths. All of the World Health Organization-recommended insecticides for mosquito nets are pyrethroids, and vector mosquito resistance to these insecticides is one of the major obstacles to an effective malaria control program. Anopheles gambiae s.s. and Anopheles arabiensis are major malaria vectors that are widely distributed in Kenya. Two point mutations in the voltage-gated sodium channel (L1014F and L1014S) are associated with knockdown resistance (kdr) to DDT and pyrethroids in An. gambiae s.s. While the same point mutations have been reported to be rare in An. arabiensis, some evidence of metabolic resistance has been reported in this species. In order to determine the distribution of the point mutation L1014S in An. gambiae s.s. and An. arabiensis in southern and western Kenya, we collected larvae and screened for the mutation by DNA sequencing. We found high allelic and homozygous frequencies of the L1014S mutation in An. gambiae s.s. The L1014S mutation was also widely distributed in An. arabiensis, although the allelic frequency was lower than in An. gambiae s.s. The same intron sequence (length: 57 base) found in both species indicated that the mutation was introgressed by hybridization. The allelic frequency of L1014S was higher in both species in western regions, demonstrating the strong selection pressure imposed by long-lasting insecticide-treated nets (LLITN)/ITN on the An. gambiae s.s. and An. arabiensis populations in those areas. The present contribution of the L1014S mutation to pyrethroid resistance in An. arabiensis may be negligible. However, the homozygous frequency could increase with continuing selection pressure due to expanded LLITN coverage in the future.This publication has 23 references indexed in Scilit:
- Spatial and temporal variation in the kdr allele L1014S in Anopheles gambiae s.s. and phenotypic variability in susceptibility to insecticides in Western KenyaMalaria Journal, 2011
- Distribution of the main malaria vectors in KenyaMalaria Journal, 2010
- Anopheles gambiae: historical population decline associated with regional distribution of insecticide-treated bed nets in western Nyanza Province, KenyaMalaria Journal, 2010
- Insecticide resistance in Anopheles arabiensis (Diptera: Culicidae) from villages in central, northern and south west Ethiopia and detection of kdr mutationParasites & Vectors, 2010
- The risks of malaria infection in Kenya in 2009BMC Infectious Diseases, 2009
- Pyrethroid resistance in the major malaria vector Anopheles arabiensis from Gwave, a malaria-endemic area in ZimbabweMalaria Journal, 2008
- Insecticide resistance in Anopheles gambiae from south-western Chad, Central AfricaMalaria Journal, 2008
- Distribution of knock-down resistance mutations in Anopheles gambiae molecular forms in west and west-central AfricaMalaria Journal, 2008
- Effect of expanded insecticide-treated bednet coverage on child survival in rural Kenya: a longitudinal studyThe Lancet, 2007
- Increasing Coverage and Decreasing Inequity in Insecticide-Treated Bed Net Use among Rural Kenyan ChildrenPLoS Medicine, 2007