title: Diagnostic doses and times for Phlebotomus papatasi and Lutzomyia longipalpis sand flies (Diptera: Psychodidae: Phlebotominae) using the CDC bottle bioassay to assess insecticide resistance.
abstract: BACKGROUND
  Insecticide resistance to synthetic chemical insecticides is a worldwide concern in phlebotomine sand flies (Diptera: Psychodidae), the vectors of Leishmania spp. parasites. The CDC bottle bioassay assesses resistance by testing populations against verified diagnostic doses and diagnostic times for an insecticide, but the assay has been used limitedly with sand flies. The objective of this study was to determine diagnostic doses and diagnostic times for laboratory Lutzomyia longipalpis (Lutz & Nieva) and Phlebotomus papatasi (Scopoli) to ten insecticides, including pyrethroids, organophosphates, carbamates, and DDT, that are used worldwide to control vectors.
  
  
  METHODS
  Bioassays were conducted in 1,000-ml glass bottles each containing 10-25 sand flies from laboratory colonies of L. longipalpis or P. papatasi. Four pyrethroids, three organophosphates, two carbamates and one organochlorine, were evaluated. A series of concentrations were tested for each insecticide, and four replicates were conducted for each concentration. Diagnostic doses were determined only during the exposure bioassay for the organophosphates and carbamates. For the pyrethroids and DDT, diagnostic doses were determined for both the exposure bioassay and after a 24-hour recovery period.
  
  
  RESULTS
  Both species are highly susceptible to the carbamates as their diagnostic doses are under 7.0 μg/ml. Both species are also highly susceptible to DDT during the exposure assay as their diagnostic doses are 7.5 μg/ml, yet their diagnostic doses for the 24-h recovery period are 650.0 μg/ml for Lu. longipalpis and 470.0 μg/ml for P. papatasi.
  
  
  CONCLUSIONS
  Diagnostic doses and diagnostic times can now be incorporated into vector management programs that use the CDC bottle bioassay to assess insecticide resistance in field populations of Lu. longipalpis and P. papatasi. These findings provide initial starting points for determining diagnostic doses and diagnostic times for other sand fly vector species and wild populations using the CDC bottle bioassay.
authors.affiliation: Department of Biology, Utah State University, Logan, Utah, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Denlinger
authors.affiliation: Department of Biology, Utah State University, Logan, Utah, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Creswell
authors.affiliation: Department of Biology, Utah State University, Logan, Utah, USA.
authors.forename: J Laine
authors.initials: JL
authors.lastname: Anderson
authors.affiliation: Department of Biology, Utah State University, Logan, Utah, USA.
authors.forename: Conor K
authors.initials: CK
authors.lastname: Reese
authors.affiliation: Department of Biology, Utah State University, Logan, Utah, USA. scott.bernhardt@usu.edu.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Bernhardt
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D002487:Centers for Disease Control and Prevention, U.S.; D004305:Dose-Response Relationship, Drug; D007303:Insect Vectors / Q000187:drug effects*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D010755:Organophosphates / Q000494:pharmacology; D010691:Phlebotomus / Q000187:drug effects*; D011576:Psychodidae / Q000187:drug effects*; D011722:Pyrethrins / Q000494:pharmacology; D014481:United States
chemical_list: D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins
keywords: Bottle bioassay; CDC; Carbamate; DDT; Insecticide resistance; Lutzomyia longipalpis; Organophosphate; Phlebotomus papatasi; Pyrethroid; WHO