Assessment of benzimidazole resistance in Haemonchus contortus in sheep flocks in Ontario, Canada: comparison of detection methods for drug resistance
| Autor: | Virginie Barrère, Roger K. Prichard, Andrew S. Peregrine, Paula I. Menzies, K.P. Shakya, Laura C. Falzon |
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| Rok vydání: | 2013 |
| Předmět: |
Benzimidazole
Veterinary medicine Drug Resistance Sheep Diseases Drug resistance Biology chemistry.chemical_compound Feces parasitic diseases medicine Animals Allele frequency Parasite Egg Count Anthelmintics Ontario Sheep General Veterinary General Medicine biology.organism_classification chemistry Genetic marker Larva Fenbendazole Pyrosequencing Parasitology Benzimidazoles Haemonchus Flock Haemonchiasis Haemonchus contortus medicine.drug |
| Zdroj: | Veterinary parasitology. 198(1-2) |
| ISSN: | 1873-2550 |
| Popis: | In 2011, a field study was conducted to assess drug resistance of gastro-intestinal nematodes in sheep flocks in Ontario, Canada. Benzimidazole resistance in Haemonchus contortus was assessed by genetic analysis of eggs; measurement of resistant allele percentages at codons 167, 198 and 200 in the β-tubulin gene was determined on pools of H. contortus eggs using pyrosequencing. Susceptibility to benzimidazoles in gastro-intestinal nematodes was also determined using a Faecal Egg Count Reduction Test (FECRT) and a Larval Development Assay (LDA). In total, 16 farms were assessed with the genetic test. Based on resistant allele frequencies, all of the farms (16/16) tested had benzimidazole resistance in H. contortus; the overall percentage of benzimidazole-resistant H. contortus (estimated prior to treatment using the Hardy–Weinberg formula) was 68.5%. The FECRT and LDA were performed on 11 and 13 farms, respectively. Resistance to fenbendazole was detected on 100% (11/11) of the farms where the FECRT was performed. The LDA revealed the presence of thiabendazole resistance in H. contortus in 92% (12/13) of the farms. Estimated percentages of resistant parasites in H. contortus populations obtained with the two biological tests and the genetic test were compared. The results of the genetic test were in agreement with the biological tests and confirmed that benzimidazole resistance in H. contortus is present in Ontario sheep flocks. Differences between the different methods of drug resistance detection are discussed in terms of cost, time and sampling. |
| Databáze: | OpenAIRE |
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