title: Late-acting dominant lethal genetic systems and mosquito control.
abstract: BACKGROUND
  Reduction or elimination of vector populations will tend to reduce or eliminate transmission of vector-borne diseases. One potential method for environmentally-friendly, species-specific population control is the Sterile Insect Technique (SIT). SIT has not been widely used against insect disease vectors such as mosquitoes, in part because of various practical difficulties in rearing, sterilization and distribution. Additionally, vector populations with strong density-dependent effects will tend to be resistant to SIT-based control as the population-reducing effect of induced sterility will tend to be offset by reduced density-dependent mortality.
  
  
  RESULTS
  We investigated by mathematical modeling the effect of manipulating the stage of development at which death occurs (lethal phase) in an SIT program against a density-dependence-limited insect population. We found late-acting lethality to be considerably more effective than early-acting lethality. No such strains of a vector insect have been described, so as a proof-of-principle we constructed a strain of the principal vector of the dengue and yellow fever viruses, Aedes (Stegomyia) aegypti, with the necessary properties of dominant, repressible, highly penetrant, late-acting lethality.
  
  
  CONCLUSIONS
  Conventional SIT induces early-acting (embryonic) lethality, but genetic methods potentially allow the lethal phase to be tailored to the program. For insects with strong density-dependence, we show that lethality after the density-dependent phase would be a considerable improvement over conventional methods. For density-dependent parameters estimated from field data for Aedes aegypti, the critical release ratio for population elimination is modeled to be 27% to 540% greater for early-acting rather than late-acting lethality. Our success in developing a mosquito strain with the key features that the modeling indicated were desirable demonstrates the feasibility of this approach for improved SIT for disease control.
authors: Department of Zoology, University of Oxford, South Parks Road, Oxford, UK. hoangkim.phuc@zoo.ox.ac.uk <hoangkim.phuc@zoo.ox.ac.uk>
authors: Hoang Kim
authors: HK
authors: Phuc
authors: Morten H
authors: MH
authors: Andreasen
authors: Rosemary S
authors: RS
authors: Burton
authors: Céline
authors: C
authors: Vass
authors: Matthew J
authors: MJ
authors: Epton
authors: Gavin
authors: G
authors: Pape
authors: Guoliang
authors: G
authors: Fu
authors: Kirsty C
authors: KC
authors: Condon
authors: Sarah
authors: S
authors: Scaife
authors: Christl A
authors: CA
authors: Donnelly
authors: Paul G
authors: PG
authors: Coleman
authors: Helen
authors: H
authors: White-Cooper
authors: Luke
authors: L
authors: Alphey
mesh_terms: D000330:Aedes / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D000818:Animals; D030801:Animals, Genetically Modified; D005260:Female; D005799:Genes, Dominant / Q000235:genetics*; D005804:Genes, Lethal / Q000235:genetics*; D005818:Genetic Engineering; D007246:Infertility / Q000235:genetics / Q000503:physiopathology; D007814:Larva / Q000235:genetics / Q000502:physiology; D008136:Longevity / Q000235:genetics / Q000502:physiology; D008297:Male; D008954:Models, Biological; D009032:Mosquito Control / Q000379:methods*; D011156:Population Density; D011679:Pupa / Q000235:genetics / Q000502:physiology; D013752:Tetracycline / Q000494:pharmacology; D013997:Time Factors
chemical_list: D013752:Tetracycline