Anthelmintic efficacy of low-dose phenothiazine against strains of sheep nematodes susceptible or resistant to thiabendazole, levamisole and morantel tartrate: effect on patent infections.
The anthelmintic efficacy of low-dose phenothiazine therapy, administered as a 1:40 phenothiazine: molasses mixture, was tested against patent infections of strains of Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia spp susceptible or resistant to thiabendazole (an other benzimidazoles), levamisole and morantel tartrate. Phenothiazine reduced faecal egg output for both susceptible and resistant strains of all three nematodes. In daily doses of 0.25 g per sheep per day and above it completely inhibited larval production in susceptible strains. Against resistant strains, there was a reduced efficiency with 82.3 per cent inhibition of egg hatch at the 0.25 g per sheep per day level. Phenothiazine treatment had no significant effect on worm numbers for either susceptible or resistant worms. It is suggested that benzimidazole-resistant strains may be cross-resistant to phenothiazine.
D000818:Animals; D004351:Drug Resistance; D006188:Haemonchiasis / Q000188:drug therapy / Q000662:veterinary; D007978:Levamisole / Q000494:pharmacology; D008297:Male; D009015:Morantel / Q000494:pharmacology; D010029:Ostertagiasis / Q000188:drug therapy / Q000662:veterinary; D010640:Phenothiazines / Q000008:administration & dosage* / Q000627:therapeutic use; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy*; D013827:Thiabendazole / Q000494:pharmacology; D014251:Trichostrongyloidea / Q000187:drug effects*; D014252:Trichostrongyloidiasis / Q000662:veterinary*; D014253:Trichostrongylosis / Q000188:drug therapy / Q000662:veterinary
D010640:Phenothiazines; D007978:Levamisole; D009015:Morantel; D013827:Thiabendazole