title: Anthelmintic resistance to ivermectin and moxidectin in gastrointestinal nematodes of cattle in Europe.
abstract: Anthelmintic resistance has been increasingly reported in cattle worldwide over the last decade, although reports from Europe are more limited. The objective of the present study was to evaluate the efficacy of injectable formulations of ivermectin and moxidectin at 0.2 mg per kg bodyweight against naturally acquired gastro-intestinal nematodes in cattle. A total of 753 animals on 40 farms were enrolled in Germany (12 farms), the UK (10 farms), Italy (10 farms), and France (8 farms). Animals were selected based on pre-treatment faecal egg counts and were allocated to one of the two treatment groups. Each treatment group consisted of between 7 and 10 animals. A post-treatment faecal egg count was performed 14 days (±2 days) after treatment. The observed percentage reduction was calculated for each treatment group based on the arithmetic mean faecal egg count before and after treatment. The resistance status was evaluated based on the reduction in arithmetic mean faecal egg count and both the lower and upper 95% confidence limits. A decreased efficacy was observed in half or more of the farms in Germany, France and the UK. For moxidectin, resistance was confirmed on 3 farms in France, and on 1 farm in Germany and the UK. For ivermectin, resistance was confirmed on 3 farms in the UK, and on 1 farm in Germany and France. The remaining farms with decreased efficacy were classified as having an inconclusive resistance status based on the available data. After treatment Cooperia spp. larvae were most frequently identified, though Ostertagia ostertagi was also found, in particular within the UK and Germany. The present study reports lower than expected efficacy for ivermectin and moxidectin (based on the reduction in egg excretion after treatment) on European cattle farms, with confirmed anthelmintic resistance on 12.5% of the farms.
authors.affiliation: Zoetis, Mercuriusstraat 20, 1930, Zaventem, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Geurden
authors.affiliation: LUNAM University, ONIRIS, Nantes-Atlantic College of Veterinary Medicine, Food Science and Engineering, UMR 1300 BIOEPAR, Nantes, F-44307, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chartier
authors.affiliation: Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Germany.
authors.forename: Jane
authors.initials: J
authors.lastname: Fanke
authors.affiliation: Department of Animal Medicine, Production and Health, University of Padua, Padua, Italy.
authors.forename: Antonio Frangipane
authors.initials: AF
authors.lastname: di Regalbono
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, 64100, Teramo, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Traversa
authors.affiliation: Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: von Samson-Himmelstjerna
authors.affiliation: Institute of Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Germany.
authors.forename: Janina
authors.initials: J
authors.lastname: Demeler
authors.affiliation: Zoetis, 333 Portage Street, Kalamazoo, MI, 49007-4931, USA.
authors.forename: Hima Bindu
authors.initials: HB
authors.lastname: Vanimisetti
authors.affiliation: Zoetis, 23/25 avenue du Docteur Lannelongue, 75668, Paris Cedex 14, France.
authors.forename: David J
authors.initials: DJ
authors.lastname: Bartram
authors.affiliation: Department of Large Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Denwood
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology*; D004351:Drug Resistance; D005060:Europe / Q000453:epidemiology; D005243:Feces / Q000469:parasitology; D007559:Ivermectin / Q000494:pharmacology / Q000627:therapeutic use*; D018942:Macrolides / Q000494:pharmacology / Q000627:therapeutic use*; D009348:Nematoda / Q000187:drug effects*; D009349:Nematode Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D010270:Parasite Egg Count
chemical_list: D000871:Anthelmintics; D018942:Macrolides; D007559:Ivermectin; C027837:moxidectin
keywords: Anthelmintic resistance; Cattle; Europe; Ivermectin; Moxidectin