title: Visceral Leishmaniasis on the Indian Subcontinent: Modelling the Dynamic Relationship between Vector Control Schemes and Vector Life Cycles.
abstract: Visceral leishmaniasis (VL) is a disease caused by two known vector-borne parasite species (Leishmania donovani, L. infantum), transmitted to man by phlebotomine sand flies (species: Phlebotomus and Lutzomyia), resulting in ≈50,000 human fatalities annually, ≈67% occurring on the Indian subcontinent. Indoor residual spraying is the current method of sand fly control in India, but alternative means of vector control, such as the treatment of livestock with systemic insecticide-based drugs, are being evaluated. We describe an individual-based, stochastic, life-stage-structured model that represents a sand fly vector population within a village in India and simulates the effects of vector control via fipronil-based drugs orally administered to cattle, which target both blood-feeding adults and larvae that feed on host feces.
  
  
  
  Simulation results indicated efficacy of fipronil-based control schemes in reducing sand fly abundance depended on timing of drug applications relative to seasonality of the sand fly life cycle. Taking into account cost-effectiveness and logistical feasibility, two of the most efficacious treatment schemes reduced population peaks occurring from April through August by ≈90% (applications 3 times per year at 2-month intervals initiated in March) and >95% (applications 6 times per year at 2-month intervals initiated in January) relative to no control, with the cumulative number of sand fly days occurring April-August reduced by ≈83% and ≈97%, respectively, and more specifically during the summer months of peak human exposure (June-August) by ≈85% and ≈97%, respectively.
  
  
  
  Our model should prove useful in a priori evaluation of the efficacy of fipronil-based drugs in controlling leishmaniasis on the Indian subcontinent and beyond.
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, United States of America.
authors.forename: David M
authors.initials: DM
authors.lastname: Poché
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, United States of America.
authors.forename: William E
authors.initials: WE
authors.lastname: Grant
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Hsiao-Hsuan
authors.initials: HH
authors.lastname: Wang
mesh_terms: D000328:Adult; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000469:parasitology / Q000517:prevention & control; D003140:Communicable Disease Control / Q000191:economics / Q000379:methods* / Q000706:statistics & numerical data; D003198:Computer Simulation; D006801:Humans; D007194:India / Q000453:epidemiology; D007303:Insect Vectors / Q000187:drug effects / Q000254:growth & development / Q000469:parasitology; D007306:Insecticides / Q000008:administration & dosage*; D007893:Leishmania donovani / Q000187:drug effects; D007896:Leishmaniasis / Q000188:drug therapy / Q000517:prevention & control* / Q000662:veterinary; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control*; D008297:Male; D015233:Models, Statistical; D010691:Phlebotomus / Q000187:drug effects / Q000254:growth & development / Q000469:parasitology; D011720:Pyrazoles / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D007306:Insecticides; D011720:Pyrazoles; C082360:fipronil