Comparison of three in vitro techniques to estimate benzimidazole resistance in Haemonchus contortus of sheep.
Three in vitro assays to detect benzimidazole resistance, namely, the egg-hatch assay, tubulin-binding assay, and a larval-development assay, were evaluated by estimating the level of benzimidazole resistance in three field isolates of Haemonchus contortus compared with a susceptible reference strain. Comparisons were also made with estimates of benzimidazole resistance of the three field strains obtained from an in vivo controlled anthelmintic efficacy test. All three in vitro tests showed similar, consistent results which also suggested greater sensitivity than the in vivo assay. These results indicate that selection of an in vitro technique to determine benzimidazole resistance should therefore be based on considerations other than precision, such as technical expertise, availability of equipment, cost and speed in which diagnosis is required.
Johansen
M V
MV
Institute of Hygiene and Microbiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
Waller
P J
PJ
D000704:Analysis of Variance; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology*; D004351:Drug Resistance; D006188:Haemonchiasis / Q000469:parasitology / Q000662:veterinary; D006189:Haemonchus / Q000187:drug effects*; D007814:Larva / Q000187:drug effects; D010063:Ovum / Q000187:drug effects; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology; D014251:Trichostrongyloidea / Q000187:drug effects*; D014404:Tubulin / Q000378:metabolism
D001562:Benzimidazoles; D014404:Tubulin