title: Levels of insecticide resistance to deltamethrin, malathion, and temephos, and associated mechanisms in Aedes aegypti mosquitoes from the Guadeloupe and Saint Martin islands (French West Indies).
abstract: BACKGROUND
  In the Guadeloupe and Saint Martin islands, Aedes aegypti mosquitoes are the only recognized vectors of dengue, chikungunya, and Zika viruses. For around 40 years, malathion was used as a mosquito adulticide and temephos as a larvicide. Since the European Union banned the use of these two insecticide molecules in the first decade of the 21st century, deltamethrin and Bacillus thuringiensis var. israelensis are the remaining adulticide and larvicide, respectively, used in Guadeloupe. In order to improve the management of vector control activities in Guadeloupe and Saint Martin, we investigated Ae. aegypti resistance to and mechanisms associated with deltamethrin, malathion, and temephos.
  
  
  METHODS
  Ae. aegypti mosquitoes were collected from six different localities of Guadeloupe and Saint Martin. Larvae were used for malathion and temephos bioassays, and adult mosquitoes for deltamethrin bioassays, following World Health Organization recommendations. Knockdown resistance (Kdr) genotyping for V1016I and F1534C mutations, and expression levels of eight enzymes involved in detoxification mechanisms were examined in comparison with the susceptible reference Bora Bora strain.
  
  
  RESULTS
  Resistance ratios (RR50) calculated for Ae. aegypti larvae showed high resistance levels to temephos (from 8.9 to 33.1-fold) and low resistance levels to malathion (from 1.7 to 4.4-fold). Adult females displayed moderate resistance levels to deltamethrin regarding the time necessary to affect 50% of individuals, varying from 8.0 to 28.1-fold. Molecular investigations on adult mosquitoes showed high resistant allele frequencies for V1016I and F1534C (from 85 to 96% and from 90 to 98%, respectively), as well as an overexpression of the glutathione S-transferase gene, GSTe2, the carboxylesterase CCEae3a, and the cytochrome genes 014614, CYP6BB2, CYP6M11, and CYP9J23.
  
  
  CONCLUSIONS
  Ae. aegypti populations from Guadeloupe and Saint Martin exhibit multiple resistance to organophosphates (temephos and malathion), and pyrethroids (deltamethrin). The mechanisms associated with these resistance patterns show strong frequencies of F1534C and V1016I Kdr mutations, and an over-expression of CCEae3a, GSTe2, and four cytochrome P450 genes (014614, CYP9J23, CYP6M11, CYP6BB2). These results will form the baseline for a deeper understanding of the insecticide resistance levels and associated mechanisms of Ae. aegypti populations and will be used to improve vector control strategies in Guadeloupe and Saint Martin.
authors.affiliation: Laboratory of Medical Entomology, Unit Environment and Health, Pasteur Institute of Guadeloupe, 97183, Les Abymes, Guadeloupe. daniella.goindin@gmail.com.
authors.forename: Daniella
authors.initials: D
authors.lastname: Goindin
authors.affiliation: Laboratory of Medical Entomology, Unit Environment and Health, Pasteur Institute of Guadeloupe, 97183, Les Abymes, Guadeloupe.
authors.forename: Christelle
authors.initials: C
authors.lastname: Delannay
authors.affiliation: Laboratory of Medical Entomology, Unit Environment and Health, Pasteur Institute of Guadeloupe, 97183, Les Abymes, Guadeloupe.
authors.forename: Andric
authors.initials: A
authors.lastname: Gelasse
authors.affiliation: Vector control Service, Regional Health Agency, Dothémare, Les Abymes, Guadeloupe.
authors.forename: Cédric
authors.initials: C
authors.lastname: Ramdini
authors.affiliation: Alpine Ecology Laboratory (LECA), CNRS, UMR 5553, 2233 rue de la piscine BP53, 38041, Grenoble, Cedex 9, France.|University of Grenoble Alpes, Grenoble, France.|Environmental and Systems Biology (BEeSy), University of Grenoble Alpes, Grenoble, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Gaude
authors.affiliation: Alpine Ecology Laboratory (LECA), CNRS, UMR 5553, 2233 rue de la piscine BP53, 38041, Grenoble, Cedex 9, France.|University of Grenoble Alpes, Grenoble, France.|Environmental and Systems Biology (BEeSy), University of Grenoble Alpes, Grenoble, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Faucon
authors.affiliation: Alpine Ecology Laboratory (LECA), CNRS, UMR 5553, 2233 rue de la piscine BP53, 38041, Grenoble, Cedex 9, France.|University of Grenoble Alpes, Grenoble, France.|Environmental and Systems Biology (BEeSy), University of Grenoble Alpes, Grenoble, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: David
authors.affiliation: Vector control Service, Regional Health Agency, Dothémare, Les Abymes, Guadeloupe.
authors.forename: Joël
authors.initials: J
authors.lastname: Gustave
authors.affiliation: Laboratory of Medical Entomology, Unit Environment and Health, Pasteur Institute of Guadeloupe, 97183, Les Abymes, Guadeloupe.
authors.forename: Anubis
authors.initials: A
authors.lastname: Vega-Rua
authors.affiliation: Vector Environment and Society Unit, Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, 20, Avenue Appia, CH-1211, Geneva 27, Switzerland.
authors.forename: Florence
authors.initials: F
authors.lastname: Fouque
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D000818:Animals; D001681:Biological Assay; D004199:Disease Vectors; D005260:Female; D020869:Gene Expression Profiling; D060005:Genotyping Techniques; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D008294:Malathion / Q000494:pharmacology*; D020125:Mutation, Missense; D009570:Nitriles / Q000494:pharmacology*; D011722:Pyrethrins / Q000494:pharmacology*; D000002:Temefos / Q000494:pharmacology*; D014900:West Indies
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin; D000002:Temefos; D008294:Malathion
keywords: Aedes aegypti; Deltamethrin; Guadeloupe; Insecticide resistance; Malathion; Mosquitoes; Saint Martin; Temephos