Morphological changes in trichostrongylid eggs after treatment with fenbendazole.
The influence of daily doses of 0.05-0.1 mg fenbendazole/kg body weight on egg development was tested in twenty-seven lambs artificially infected with Haemonchus contortus plus Trichostrongylus colubriformis or Ostertagia circumcincta, as well as in two additional sheep naturally infected with Nematodirus spp. Atypical eggs were detected before a reduction in the number of eggs. Atypical eggs had blastomeres of different sizes and shapes; knot-like, crater-like or bubble-like. In isolated cases eggs with atypical first larvae were recognizable. Morphologically changes eggs occurred in the reproductive organs of female O. circumcincta worms. None, or only a very small number of third stage larvae, could be cultured from the faeces of treated sheep.
D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology*; D005260:Female; D005273:Fenbendazole / Q000494:pharmacology*; D008297:Male; D010063:Ovum / Q000166:cytology*; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology*; D014251:Trichostrongyloidea / Q000187:drug effects / Q000502:physiology*; D014252:Trichostrongyloidiasis / Q000469:parasitology / Q000662:veterinary*
D001562:Benzimidazoles; D005273:Fenbendazole