Further potential limitations of the undifferentiated faecal egg count reduction test for the detection of anthelmintic resistance in sheep

Authors: McKenna PB
Publication: New Zealand Veterinary Journal, Volume 45, Issue 6, pp 244-246, Dec 1997
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Alimentary system/gastroenterology, Animal remedies/veterinary medicines, Anthelmintics, Parasite control, Parasites - internal, Diagnostic procedures, Nematode, Treatment/therapy
Article class: Short Communication

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Abstract: Fifteen (36%) of 42 mixed gastro-intestinal nematode infections in sheep, identified as drench-susceptible by the undifferentiated faecal egg count reduction test, were found to harbour anthelmintic-resistant worms when analysed on the basis of changes in the egg counts of individual nematode genera. Most of these cases involved resistance in a single nematode genus, with Ostertagia and Trichostrongylus being implicated most frequently. The possible contributory role of larval culture results in helping to reduce the chances of the faecal egg count reduction test producing these and similar types of errors is discussed.

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