title: Efficacy of ULV and thermal aerosols of deltamethrin for control of Aedes albopictus in nice, France.
abstract: Ultra-low volume (ULV) insecticidal aerosols dispensed from vehicle-mounted cold-foggers are widely considered the method of choice for control of Aedes aegypti and Ae. albopictus during outbreaks of dengue and chikungunya and, more recently, Zika. Nevertheless, their effectiveness has been poorly studied, particularly in Europe. Nearly all published studies of ULV efficacy are bio-assays based on the mortality of caged mosquitoes. In our study we preferred to monitor the direct impact of treatments on the wild mosquito populations. This study was undertaken to evaluate the efficiency of the two widely used space spraying methods to control Ae. albopictus and Ae. aegypti.
  
  
  
  We determined the susceptibility of local Ae. albopictus to deltamethrin by two methods: topical application and the "WHO Tube Test". We used ovitraps baited with hay infusion and adult traps (B-G Sentinel) baited with a patented attractant to monitor the mosquitoes in four residential areas in Nice, southern France. The impact of deltamethrin applied from vehicle-mounted ULV fogging-machines was assessed by comparing trap results in treated vs untreated areas for 5 days before and 5 days after treatment. Four trials were conducted at the maximum permitted application rate (1 g.ha-1). We also made two small-scale tests of the impact of the same insecticide dispensed from a hand-held thermal fogger.
  
  
  
  Susceptibility to the insecticide was high but there was no discernable change in the oviposition rate or the catch of adult female mosquitoes, nor was there any change in the parous rate. In contrast, hand-held thermal foggers were highly effective, with more than 90% reduction of both laid eggs and females.
  
  
  
  We believe that direct monitoring of the wild mosquito populations gives a realistic assessment of the impact of treatments and suggest that the lack of efficacy is due to lack of interaction between the target mosquitoes and the ULV aerosol. We discuss the factors that influence the effectiveness of both methods of spraying in the context of epidemic situations.
authors.affiliation: EID Méditerranée, Montpellier, France. saidboubidi@yahoo.fr.|Service Eco-épidémiologie parasitaire, Institut Pasteur, Algiers, Algeria. saidboubidi@yahoo.fr.
authors.forename: Saïd C
authors.initials: SC
authors.lastname: Boubidi
authors.affiliation: UMR Mivegec, IRD, CNRS et Université de Montpellier, Montpellier, France.
authors.forename: David
authors.initials: D
authors.lastname: Roiz
authors.affiliation: UMR Mivegec, IRD, CNRS et Université de Montpellier, Montpellier, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Rossignol
authors.affiliation: UMR Mivegec, IRD, CNRS et Université de Montpellier, Montpellier, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Chandre
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Benoit
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Raselli
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Tizon
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Cadiou
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Reda
authors.initials: R
authors.lastname: Tounsi
authors.affiliation: EID Méditerranée, Montpellier, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lagneau
authors.affiliation: UMR Mivegec, IRD, CNRS et Université de Montpellier, Montpellier, France.|Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
authors.forename: Didier
authors.initials: D
authors.lastname: Fontenille
authors.affiliation: Unité Insectes et Maladies Infectieuses, Institut Pasteur, Paris, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Reiter
mesh_terms: D000330:Aedes / Q000187:drug effects*; D000336:Aerosols / Q000494:pharmacology*; D000818:Animals; D001681:Biological Assay; D005602:France; D007306:Insecticides / Q000494:pharmacology*; D009032:Mosquito Control / Q000379:methods; D009570:Nitriles / Q000494:pharmacology*; D011722:Pyrethrins / Q000494:pharmacology*; D013696:Temperature
chemical_list: D000336:Aerosols; D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin
keywords: Aedes albopictus; Cold fogging; Deltamethrin; Dengue; Thermal fogging; ULV; Vector control