title: Treatment of livestock with systemic insecticides for control of Anopheles arabiensis in western Kenya.
abstract: BACKGROUND
  Despite the implementation of vector control strategies, including insecticide-treated bed nets (ITN) and indoor residual spraying (IRS) in western Kenya, this area still experiences high level of malaria transmission. Novel vector control tools are required which target such vector species, such as Anopheles arabiensis, that feed outdoors and have minimal contact with ITNs and IRS.
  
  
  METHODS
  To address this need, ivermectin, eprinomectin, and fipronil were evaluated in Zebu cattle under semi-field conditions to evaluate the potential of these compounds to reduce the survival of blood feeding An. arabiensis. Over the course of four experiments, lactating cattle received doses of oral ivermectin at 0.1 or 0.2 mg/kg, oral eprinomectin at 0.2 or 0.5 mg/kg, topical eprinomectin at 0.5, 0.75, or 1.5 mg/kg, or oral fipronil at 0.25, 0.5, 1.0, or 1.5 mg/kg. On days 1, 3, 5, 7, 14, and 21 days post-treatment, cattle were exposed to An. arabiensis, and mosquito mortality post-blood feeding was monitored. For the analysis of survival data, the Kaplan-Meier estimator and Mantel-Haenszel test was used to contrast the treatment and control survival functions.
  
  
  RESULTS
  All three compounds significantly reduced the survival time of An. arabiensis. Twenty-one days post-treatment, mortality of mosquitoes fed on cattle dosed orally with 0.2 or 0.5 mg/kg eprinomectin, topically with eprinomectin at 0.5 mg/kg, or orally with either 1.0 or 1.5 mg/kg fipronil was still significantly higher than control mortality.
  
  
  CONCLUSIONS
  These data demonstrate the effectiveness of three insecticidal compounds administered systemically to cattle for controlling the cattle-feeding mosquito An. arabiensis. Eprinomectin and fipronil provided the longest-lasting control. Such endectocidal treatments in cattle are a promising new strategy for control of residual, outdoor malaria transmission and could effectively augment current interventions which target more endophilic vector species.
authors.affiliation: Genesis Laboratories, P.O. Box 1195, Wellington, CO, 80549, USA. richard@genesislabs.com.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Poché
authors.affiliation: Genesis Laboratories, P.O. Box 1195, Wellington, CO, 80549, USA. dylanburruss@gmail.com.
authors.forename: Dylan
authors.initials: D
authors.lastname: Burruss
authors.affiliation: Genesis Laboratories, P.O. Box 1195, Wellington, CO, 80549, USA. larisap@genesislabs.com.
authors.forename: Larisa
authors.initials: L
authors.lastname: Polyakova
authors.affiliation: Genesis Laboratories, P.O. Box 1195, Wellington, CO, 80549, USA. davidp@genesislabs.com.
authors.forename: David M
authors.initials: DM
authors.lastname: Poché
authors.affiliation: Genesis Laboratories, P.O. Box 1195, Wellington, CO, 80549, USA. rajesh@genesislabs.com.
authors.forename: Rajesh B
authors.initials: RB
authors.lastname: Garlapati
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D001681:Biological Assay; D002417:Cattle; D007303:Insect Vectors / Q000187:drug effects*; D007306:Insecticides / Q000008:administration & dosage* / Q000494:pharmacology*; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D053208:Kaplan-Meier Estimate; D007630:Kenya; D008288:Malaria / Q000517:prevention & control*; D009032:Mosquito Control / Q000379:methods*; D011720:Pyrazoles / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D007306:Insecticides; D011720:Pyrazoles; D007559:Ivermectin; C101434:eprinomectin; C082360:fipronil