Anthelmintic activity of the macrocyclic lactone F28249-alpha in sheep.
The macrolytic lactone F28249-alpha was titrated in experimentally infected sheep and found to be highly effective against most of the common gastrointestinal nematodes as a single oral dose, given at a rate of 0.025, 0.05, or 0.1 mg/kg. Specifically, maximal activity was evident at even the lowest dosage against adult Haemonchus contortus, Ostertagia circumcinta, Trichostrongylus axei, and T colubriformis and L4 O circumcinta. Activity against Oesophagostomum columbianum was also high at all dosages, with a calculated ED95 of 0.029 mg/kg. Cooperia curticei was eliminated at 0.1 mg/kg, but control was erratic at the lower dosages. The greatest weakness of this compound was its activity against C oncophora. The activity against this parasite was weak (less than or equal to 85%) at all dosages, and the dosage-response curve was flat, suggesting dosages substantially higher than those given would be necessary for high-order control of this species.
Shoop
W L
WL
Merck Institute for Therapeutic Research, Rahway, NJ 07065-0900.
Egerton
J R
JR
Eary
C H
CH
Suhayda
D
D
D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D000969:Antinematodal Agents / Q000494:pharmacology*; D006189:Haemonchus / Q000187:drug effects; D018942:Macrolides; D009349:Nematode Infections / Q000188:drug therapy / Q000209:etiology / Q000662:veterinary*; D010028:Ostertagia / Q000187:drug effects; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy* / Q000209:etiology; D014254:Trichostrongylus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D000969:Antinematodal Agents; D018942:Macrolides; C056041:nemadectin