title: The prevalence of anthelmintic resistance in nematode parasites of sheep in southern Latin America: Uruguay.
abstract: This survey was conducted on 252 farms randomly distributed over all the sheep raising areas in Uruguay. The study involved farms with more than 600 sheep, which represented 80% of the total sheep population of the country. Three anthelmintic groups were assessed, namely, benzimidazoles, levamisole and avermectins. Overall, the results showed 80% of sheep flocks had benzimidazole resistance, 71% had resistance to levamisole, and 1.2% of flocks showed resistance to avermectins. Approximately 28% of farms had resistance to one anthelmintic group, 64% to two anthelmintic groups, and 1% resistance to all three groups. Only 7.5% of farms had no detectable levels of anthelmintic resistance. More than 80% of farms had Trichostrongylus populations resistant to both benzimidazoles and levamisole. Resistance was recorded in all three anthelmintic groups for Haemonchus and resistance also occurred to benzimidazoles and levamisole in Ostertagia.
authors.affiliation: DILAVE, Miguel C. Rubino, Division of Parasitology, Montevideo, Uruguay.
authors.forename: A
authors.initials: A
authors.lastname: Nari
authors.forename: J
authors.initials: J
authors.lastname: Salles
authors.forename: A
authors.initials: A
authors.lastname: Gil
authors.forename: P J
authors.initials: PJ
authors.lastname: Waller
authors.forename: J W
authors.initials: JW
authors.lastname: Hansen
mesh_terms: D000383:Agriculture; D000818:Animals; D001562:Benzimidazoles / Q000627:therapeutic use; D003710:Demography; D018432:Drug Resistance, Multiple; D006189:Haemonchus / Q000187:drug effects; D007559:Ivermectin / Q000031:analogs & derivatives / Q000627:therapeutic use; D007978:Levamisole / Q000627:therapeutic use; D009348:Nematoda / Q000187:drug effects*; D009349:Nematode Infections / Q000188:drug therapy / Q000662:veterinary*; D010028:Ostertagia / Q000187:drug effects; D012756:Sheep / Q000469:parasitology*; D012757:Sheep Diseases; D013696:Temperature; D014254:Trichostrongylus / Q000187:drug effects; D014583:Uruguay
chemical_list: D001562:Benzimidazoles; D007978:Levamisole; D007559:Ivermectin; C019264:avermectin