title: Anthelmintic resistance and multidrug resistance in sheep gastro-intestinal nematodes in France, Greece and Italy.
abstract: Anthelmintic resistance (AR) in ovine gastro-intestinal nematodes has been reported to affect the health and productivity of sheep globally. The objective of the present study was to evaluate the efficacy of commonly used oral drenches in sheep in France, Greece and Italy. In each country, 10 farms were selected. On each farm, 50 animals were blocked based on the pre-treatment faecal egg count (FEC). Within each block, animals were randomly allocated to one of 5 treatment groups. In addition to an untreated control group, there were 4 groups treated per oral route: moxidectin (MOX) and ivermectin (IVM), both at 0.2mg/kg bodyweight, levamisole (LEV; at 7.5mg/kg bodyweight) and a benzimidazole (BZ; at 3.75-5mg/kg bodyweight). In France, animals were not treated with LEV, but with netobimin (NET; at 7.5mg/kg bodyweight). The FEC was monitored using a modified McMaster technique. Two weeks after treatment, individual faecal samples were taken from all animals and efficacy was calculated as the difference between arithmetic mean FEC of the control group versus each respective treatment group. The results of the present study indicate the high efficacy of treatment with oral formulations of MOX (99-100%) and IVM (98-100%) on all farms, except on 1 farm in Greece. On this farm, multi drug resistance (MDR) was identified involving 4 anthelmintics (efficacy MOX: 91%; IVM: 0%; BZ: 58% and LEV: 87%). In Greece and Italy, AR against LEV and BZ was observed on some farms, with MDR involving both anthelmintics on 3 farms in Greece and on 2 farms in Italy. In France, AR against BZ and NET was observed on all 10 farms included. In all countries, Teladorsagia sp. was the most common nematode larva identified after treatment, followed by Haemonchus sp. and Trichostrongylus sp., with differences among farms and treatments. The current study confirms the high efficacy of oral treatments with MOX and IVM, even on farms with worm populations resistant to BZ, LEV or NET. This study also reports MDR against 4 anthelmintics on one farm in Greece.
authors.affiliation: Zoetis, Veterinary Medicine Research and Development, Mercuriusstraat 20, 1930 Zaventem, Belgium. Electronic address: thomas.geurden@zoetis.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Geurden
authors.affiliation: Institut National de la Recherche Agronomique/UMT Maîtrise de la Santé des Troupeaux de Petits Ruminants/Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex, France.
authors.forename: Herve
authors.initials: H
authors.lastname: Hoste
authors.affiliation: Institut National de la Recherche Agronomique/UMT Maîtrise de la Santé des Troupeaux de Petits Ruminants/Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Jacquiet
authors.affiliation: University of Teramo, Faculty of Veterinary Medicine, Teramo, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Traversa
authors.affiliation: Veterinary Research Institute - Hellenic Agricultural Organization-Demeter (former NAGREF), Thessaloniki, Greece.
authors.forename: Smaragda
authors.initials: S
authors.lastname: Sotiraki
authors.affiliation: University of Padua, Department of Animal Medicine, Production and Health, Legnaro, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Frangipane di Regalbono
authors.affiliation: Veterinary Research Institute - Hellenic Agricultural Organization-Demeter (former NAGREF), Thessaloniki, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Tzanidakis
authors.affiliation: Veterinary Research Institute - Hellenic Agricultural Organization-Demeter (former NAGREF), Thessaloniki, Greece.
authors.forename: Despoina
authors.initials: D
authors.lastname: Kostopoulou
authors.affiliation: Institut National de la Recherche Agronomique/UMT Maîtrise de la Santé des Troupeaux de Petits Ruminants/Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex, France.
authors.forename: Christie
authors.initials: C
authors.lastname: Gaillac
authors.affiliation: Institut National de la Recherche Agronomique/UMT Maîtrise de la Santé des Troupeaux de Petits Ruminants/Ecole Nationale Vétérinaire de Toulouse, Toulouse cedex, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Privat
authors.affiliation: University of Foggia, Department of Science of Agriculture, Food and Environment, Foggia, Italy.
authors.forename: Annunziata
authors.initials: A
authors.lastname: Giangaspero
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Zanardello
authors.affiliation: Zoetis, Veterinary Medicine Research and Development, Mercuriusstraat 20, 1930 Zaventem, Belgium.
authors.forename: Laura
authors.initials: L
authors.lastname: Noé
authors.affiliation: Zoetis, Veterinary Medicine Research and Development, Kalamazoo, MI, USA.
authors.forename: Bindu
authors.initials: B
authors.lastname: Vanimisetti
authors.affiliation: Zoetis, 23/25 avenue du Docteur Lannelongue, 75668 Paris Cedex 14, France.
authors.forename: David
authors.initials: D
authors.lastname: Bartram
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000494:pharmacology*; D018432:Drug Resistance, Multiple; D005060:Europe; D005243:Feces / Q000469:parasitology; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D009348:Nematoda / Q000187:drug effects*; D009349:Nematode Infections / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D010270:Parasite Egg Count; D011897:Random Allocation; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy / Q000469:parasitology*
chemical_list: D000871:Anthelmintics
keywords: Anthelmintic resistance; Benzimidazole; Ivermectin; Moxidectin; Multidrug resistance; Sheep