title: Assessment of the combination of spinosad and milbemycin oxime in preventing the development of canine Angiostrongylus vasorum infections.
abstract: Angiostrongylus vasorum is an increasingly reported parasite in Europe that develops in dogs after ingestion of infective third stage larvae (L3) that reside in gastropod molluscs which are needed to complete the parasite's life-cycle. Infection can produce a diversity of clinical signs, determined by involvement of the respiratory, neurological, and/or coagulation system, with a likely fatal outcome in the absence of treatment. Few drugs have been shown to reliably prevent infection, and data on treatment of infections is limited. A controlled, randomized, partially blinded laboratory study was therefore executed to evaluate the efficacy and safety of a combination tablet of spinosad/milbemycin oxime in dogs inoculated with approximately 250 A. vasorum L3. Sixteen healthy nematode free adult dogs were randomly allocated to two study groups of 8 dogs each. Thirty days post inoculation (dpi) all dogs in the fed state were treated: dogs in group B were treated with spinosad and milbemycin oxime at the dose rates of 45-60 mg/kg and 0.75-1.0mg/kg bodyweight, respectively, approximately the lower half portion of the expected full unit dose range; dogs in group A were treated with placebo tablets. All dogs were euthanized and necropsied 56-58 dpi. The heart and lungs were examined to determine the presence of A. vasorum. All placebo group dogs were infected at necropsy with counts ranging from 22 to 98 adult worms and a geometric mean worm count of 55.2. In contrast, the geometric mean worm count in the spinosad/milbemycin oxime group was 0.7 with worm numbers ranging from 0 to 8. The results of this study demonstrate that a single treatment with the tablet combination of spinosad and milbemycin oxime administered 30 dpi provided 98.8% preventive efficacy against development of adult A. vasorum infections. Monthly treatments with spinosad and milbemycin oxime have the potential to prevent the establishment of infections with A. vasorum in dogs.
authors.affiliation: Institut für Parasitologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Böhm
authors.affiliation: Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 266a, CH-8057 Zurich, Switzerland.
authors.forename: Manuela
authors.initials: M
authors.lastname: Schnyder
authors.affiliation: Institut for Veterinær Sygdomsbiologi, Københavns Universitet, Dyrlægevej 100, 2, 1871 Frederiksberg C, Denmark.
authors.forename: Stig Milan
authors.initials: SM
authors.lastname: Thamsborg
authors.affiliation: Elanco Animal Health, 2500 Innovation Way, Greenfield, IN 46140, USA.
authors.forename: Caryn M
authors.initials: CM
authors.lastname: Thompson
authors.affiliation: Elanco Animal Health, 2500 Innovation Way, Greenfield, IN 46140, USA.
authors.forename: Candace
authors.initials: C
authors.lastname: Trout
authors.affiliation: Institut für Parasitologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Wolken
authors.affiliation: Elanco Animal Health, Eli Lilly and Company Limited, Basingstoke, UK. Electronic address: schnitzler_beate@elanco.com.
authors.forename: Beate
authors.initials: B
authors.lastname: Schnitzler
mesh_terms: D000801:Angiostrongylus / Q000502:physiology; D000818:Animals; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004338:Drug Combinations; D006321:Heart / Q000469:parasitology; D008168:Lung / Q000469:parasitology; D018942:Macrolides / Q000008:administration & dosage*; D017206:Strongylida Infections / Q000188:drug therapy / Q000662:veterinary*; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; D018942:Macrolides; C078973:milbemycin oxime; C415329:spinosad
keywords: Angiostrongylus vasorum; Dog; Lungworm; Milbemycin oxime; Prevention; Spinosad