title: Cross-resistance to moxidectin and ivermectin on a meat sheep farm in France.
abstract: Resistance to ivermectin and moxidectin was explored by a faecal egg count reduction test in two sheep flocks with suspected anthelmintic resistance. The FECRT confirmed one suspicion, with a mean percentage of reduction in egg excretion within the treated groups of 0% for ivermectin (CI 95%: -228 to 58) and 13% for moxidectin (CI 95%: -152 to 70). This was further explored by a controlled efficacy test. An experimental infection of 18 naïve lambs was set up using infective larvae isolated from this flock (5000 L3/lamb). Compared to the control group, abomasal worm burdens (Teladorsagia circumcincta) were reduced by 90% [CI 95%: 81.5-94.8] and 85% [CI 95%: 72.4-92.2] after ivermectin (p<0.05) and moxidectin (p<0.05) treatment respectively. Again, compared to the control group, there was a reduction for intestinal strongyles (Trichostrongylus colubriformis) of 100% and 99% [CI 95%: 97.5-99.7] for ivermectin and moxidectin respectively. No difference was found between the efficacy of moxidectin and ivermectin. Pharmacokinetic values indicated that the strongyles were submitted to anthelmintic concentrations usually lethal to them. This trial demonstrated the first multiple resistance of ovine strongyles in France.
authors: ANSES Niort Laboratory, 60 rue de Pied de Fond, CS 28440, 79024 Niort cedex, France. Electronic address: carine.paraud@anses.fr.
authors: C
authors: C
authors: Paraud
authors: VERDI R&D, Sadzot 11, 6997 Erezée, Belgium.
authors: T
authors: T
authors: Marcotty
authors: Institut National de la Recherche Agronomique, UMR 1331 INRA/INP, Toxalim Research Centre in Food Toxicology, 180 chemin de Tournefeuille-BP 93173, F-31027 Toulouse Cedex 3, France.
authors: A
authors: A
authors: Lespine
authors: Institut National de la Recherche Agronomique, UMR 1331 INRA/INP, Toxalim Research Centre in Food Toxicology, 180 chemin de Tournefeuille-BP 93173, F-31027 Toulouse Cedex 3, France.
authors: J F
authors: JF
authors: Sutra
authors: ANSES Niort Laboratory, 60 rue de Pied de Fond, CS 28440, 79024 Niort cedex, France.
authors: I
authors: I
authors: Pors
authors: Clinique Vétérinaire des Montagnes du Matin, route de Tarare, 42360 Panissières, France.
authors: I
authors: I
authors: Devos
mesh_terms: D000018:Abomasum / Q000469:parasitology; D000818:Animals; D000969:Antinematodal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002432:Cecum / Q000469:parasitology; D004351:Drug Resistance; D005243:Feces / Q000469:parasitology; D005260:Female; D005602:France; D007421:Intestine, Small / Q000469:parasitology; D007559:Ivermectin / Q000494:pharmacology* / Q000627:therapeutic use; D018942:Macrolides / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009349:Nematode Infections / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy* / Q000469:parasitology; D014251:Trichostrongyloidea / Q000187:drug effects* / Q000302:isolation & purification; D014252:Trichostrongyloidiasis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary; D014254:Trichostrongylus / Q000187:drug effects / Q000302:isolation & purification
chemical_list: D000969:Antinematodal Agents; D018942:Macrolides; D007559:Ivermectin; C027837:moxidectin
keywords: Efficacy test; FECRT; Ivermectin; Moxidectin; Pharmacokinetic parameters; Resistance; Sheep