RESISTÊNCIA AOS ANTI-HELMÍNTICOS BENZIMIDAZÓIS EM NEMATÓIDES GASTRINTESTINAIS DE PEQUENOS RUMINANTES DO SEMIÁRIDO NORDESTINO BRASILEIRO

Abstract

Resistance to benzimidazole anthelmintics is reported as an old and persistent problem in many parts of the world. Resistance development depends on the presence of resistance promoters and there are operational, genetic and bioecological factors. The objective of this work was to determine the prevalence of benzimidazole resistance and to study some variables associated with resistance development in small ruminant farms in the Brazilian northeastern semi-arid area. The work was accomplished in 25 sheep and goat farms in Limoeiro do Norte, Palhano, Jaguaruana, Itaicaba, Aracati, Alto Santo, Morada Nova and Jaguaribe municipalities, in the state of Ceara, Brazil. The procedure used to detect anthelmintic resistant nematodes was the fecal egg count reduction test. In addition, a questionnaire about management practices, infrastructure, anthelmintic usage, flocks sanitary state and veterinary assistance was applied. Data were analyzed using RESO statistical program. The questionnaires were analyzed using Spearman correlation and the simple GLM. In sheep farms, the prevalence of benzimidazole resistance was 88% and in goat farms, it was 87.5%. In sheep and goats farms, Haemonchus spp was the most prevalent genus, followed by Trichostrongylus spp and Oesophagostomum spp. Among variables studied, treatment in the dry season was statistically significant (P = 0.03), pasture rotation was not significant (P = 0.17) but has a predictable value in resistance development. KEY WORDS: Associated factors, benzimidazole, Ceara, resistance development.