title: Insecticide resistance in Culex pipiens quinquefasciatus and Aedes albopictus mosquitoes from La Réunion Island.
abstract: Resistance to insecticides was monitored on Culex pipiens quinquefasciatus mosquitoes collected in twelve localities of La Réunion, a geographically isolated island of the Indian Ocean. This mosquito is of medical concern in the region as a known vector for filariasis and a potential vector for West Nile and Rift Valley Fever viruses. Our bioassays indicated the presence of resistance to all tested insecticides, i.e. organochlorides, organophosphates and pyrethroids. A molecular investigation revealed a higher frequency of resistance genes in the coastal areas compared to elevated rural sites, probably reflecting the different nature of insecticide pressures together with the genetic cost of resistance alleles. A simple molecular test was developed to detect Rdl allele, encoding a gamma-aminobutyric acid (GABA) receptor resistant to dieldrin. Unexpectedly high Rdl frequencies were recorded over the whole island, despite this insecticide having been banned for over 15 years. This resistant allele was also detected for the first time in two samples of Aedes albopictus, a species recently involved in severe Chikungunya epidemics on the island. Rdl selection in these two mosquito species discloses current insecticide pressures in urban areas, from unknown origins, that should be taken into account to develop vector control strategies.
authors.affiliation: Université Montpellier 2, UMR CNRS 5554, Institut des Sciences de l'Evolution, Génétique de l'Adaptation, Place Eugène Bataillon, Montpellier 05, France.
authors.forename: Michaël Luciano
authors.initials: ML
authors.lastname: Tantely
authors.forename: Pablo
authors.initials: P
authors.lastname: Tortosa
authors.forename: Haoues
authors.initials: H
authors.lastname: Alout
authors.forename: Claire
authors.initials: C
authors.lastname: Berticat
authors.forename: Arnaud
authors.initials: A
authors.lastname: Berthomieu
authors.forename: Abdoul
authors.initials: A
authors.lastname: Rutee
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Dehecq
authors.forename: Patrick
authors.initials: P
authors.lastname: Makoundou
authors.forename: Pierrick
authors.initials: P
authors.lastname: Labbé
authors.forename: Nicole
authors.initials: N
authors.lastname: Pasteur
authors.forename: Mylène
authors.initials: M
authors.lastname: Weill
mesh_terms: D000110:Acetylcholinesterase / Q000235:genetics; D000330:Aedes / Q000235:genetics*; D000483:Alleles; D000818:Animals; D001483:Base Sequence; D003465:Culex / Q000235:genetics*; D004026:Dieldrin; D005260:Female; D005787:Gene Frequency; D017344:Genes, Insect; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D008297:Male; D008969:Molecular Sequence Data; D010755:Organophosphates; D011722:Pyrethrins; D018079:Receptors, GABA / Q000235:genetics; D017508:Reunion; D016415:Sequence Alignment
chemical_list: D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins; D018079:Receptors, GABA; D000110:Acetylcholinesterase; D004026:Dieldrin