The Effects of Age, Exposure History and Malaria Infection on the Susceptibility of Anopheles Mosquitoes to Low Concentrations of Pyrethroid
Open Access
- 22 September 2011
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 6 (9), e24968
- https://doi.org/10.1371/journal.pone.0024968
Abstract
Chemical insecticides are critical components of malaria control programs. Their ability to eliminate huge numbers of mosquitoes allows them to swiftly interrupt disease transmission, but that lethality also imposes immense selection for insecticide resistance. Targeting control at the small portion of the mosquito population actually responsible for transmitting malaria parasites to humans would reduce selection for resistance, yet maintain effective malaria control. Here, we ask whether simply lowering the concentration of the active ingredient in insecticide formulations could preferentially kill mosquitoes infected with malaria and/or those that are potentially infectious, namely, old mosquitoes. Using modified WHO resistance-monitoring assays, we exposed uninfected Anopheles stephensi females to low concentrations of the pyrethroid permethrin at days 4, 8, 12, and 16 days post-emergence and monitored survival for at least 30 days to evaluate the immediate and long-term effects of repeated exposure as mosquitoes aged. We also exposed Plasmodium chabaudi- and P. yoelii-infected An. stephensi females. Permethrin exposure did not consistently increase mosquito susceptibility to subsequent insecticide exposure, though older mosquitoes were more susceptible. A blood meal slightly improved survival after insecticide exposure; malaria infection did not detectably increase insecticide susceptibility. Exposure to low concentrations over successive feeding cycles substantially altered cohort age-structure. Our data suggest the possibility that, where high insecticide coverage can be achieved, low concentration formulations have the capacity to reduce disease transmission without the massive selection for resistance imposed by current practice.This publication has 41 references indexed in Scilit:
- Influence of climate on malaria transmission depends on daily temperature variationProceedings of the National Academy of Sciences of the United States of America, 2010
- Insecticide Control of Vector-Borne Diseases: When Is Insecticide Resistance a Problem?PLoS Pathogens, 2010
- How to Make Evolution-Proof Insecticides for Malaria ControlPLoS Biology, 2009
- Ecological immunology of mosquito–malaria interactionsTrends in Parasitology, 2008
- Malaria vector control by indoor residual insecticide spraying on the tropical island of Bioko, Equatorial GuineaMalaria Journal, 2007
- Insecticide resistance in the malarial mosquito Anopheles arabiensis and association with the kdr mutationMedical and Veterinary Entomology, 2007
- Anopheles and Plasmodium: from laboratory models to natural systems in the fieldEMBO Reports, 2006
- Laboratory selection for and characteristics of pyrethroid resistance in the malaria vector Anopheles funestusMedical and Veterinary Entomology, 2005
- The influence of malaria parasite genetic diversity and anaemia on mosquito feeding and fecundityParasitology, 2003
- DDT resistance in Anopheles gambiae declines with mosquito ageMedical and Veterinary Entomology, 1991