Abstract
The prevalence of anthelmintic resistance in nematodes of sheep was surveyed in 1994 on 70 farms in the Netherlands. An in vitro egg hatch assay, faecal egg count reduction (FECR) 14 days after treatment, and larval cultures were used as methods of investigation. Oxfendazole was tested on 69, ivermectin on 51, and levamisole on 36 farms. The median effective dose (ED50) of thiabendazole could be determined on 64 farms. On 60 farms (94%) the ED50 value was > or = 0.12 microgram ml-1, which is indicative of the presence of benzimidazole (BZ) resistance. On two farms egg output was too low to do a FECR test. Based on the results of the FECR test, BZ resistance was present on 56 farms (84%), on 2 farms there was a suspicion of resistance and on 9 farms no resistance could be found. No clear indications were found for the presence of resistance against ivermectin or levamisole. BZ resistance was demonstrated in Haemonchus contortus, Cooperia curticei, Ostertagia spp. and/or Trichostrongylus spp. No resistance was observed in species from the genus Nematodirus, Chabertia ovina and/or Oesophagostomum spp.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Anthelmintics / pharmacology*
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Anthelmintics / therapeutic use
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Benzimidazoles / pharmacology
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Benzimidazoles / therapeutic use
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Dose-Response Relationship, Drug
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Drug Resistance / physiology
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Feces / parasitology
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Female
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Haemonchiasis / drug therapy
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Haemonchiasis / epidemiology
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Haemonchiasis / veterinary
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Haemonchus / drug effects
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Haemonchus / isolation & purification
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Health Surveys*
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Ivermectin / pharmacology
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Ivermectin / therapeutic use
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Levamisole / pharmacology
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Levamisole / therapeutic use
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Nematoda / drug effects*
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Nematoda / isolation & purification
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Nematode Infections / drug therapy
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Nematode Infections / epidemiology
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Nematode Infections / veterinary*
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Netherlands / epidemiology
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Ostertagia / drug effects
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Ostertagia / isolation & purification
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Ostertagiasis / drug therapy
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Ostertagiasis / epidemiology
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Ostertagiasis / veterinary
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Parasite Egg Count / veterinary
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Prevalence
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Sheep
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Sheep Diseases / drug therapy*
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Sheep Diseases / epidemiology
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Sheep Diseases / parasitology
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Thiabendazole / pharmacology
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Thiabendazole / therapeutic use
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Trichostrongylosis / drug therapy
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Trichostrongylosis / epidemiology
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Trichostrongylosis / veterinary
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Trichostrongylus / drug effects
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Trichostrongylus / isolation & purification
Substances
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Anthelmintics
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Benzimidazoles
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Levamisole
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Ivermectin
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benzimidazole
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Thiabendazole
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oxfendazole