Efficacy of clorsulon against Fascioloides magna infection in sheep.
In a study to evaluate the efficacy of clorsulon against Fascioloides magna infection in sheep, 12 ewes were inoculated orally with 100 metacercariae of F magna, and 6 were treated with clorsulon (15 mg/kg of body weight) 8 weeks after inoculation. The sheep were euthanatized 16 weeks after inoculation, flukes were recovered, and the liver and other tissues were subjectively scored for the severity of lesions (0 to 4+). The number of flukes recovered from the clorsulon-treated group (3.8 +/- 1.2 flukes) was significantly (P = 0.025) lower than the number of flukes recovered from the group of untreated controls (10.0 +/- 6.6 flukes). The severity of lesions was significantly (P = 0.004) reduced (45.9%) in the treated group (2.0 +/- 1.1), compared with that in the untreated controls (3.7 +/- 0.5). In the untreated group, 3 sheep died and 1 became moribund 14 to 16 weeks after inoculation. The data suggested that a single treatment with clorsulon at a dosage of 15 mg/kg 8 weeks after inoculation was not effective in preventing F magna infection in sheep, because the survival of only a few F magna is potentially fatal in sheep within 6 months after infection.
Conboy
G A
GA
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St Paul 55108.
Stromberg
B E
BE
Schlotthauer
J C
JC
D000818:Animals; D000980:Antiplatyhelmintic Agents / Q000627:therapeutic use*; D001835:Body Weight; D005212:Fasciolidae / Q000254:growth & development; D005213:Fascioloidiasis / Q000188:drug therapy*; D005260:Female; D008099:Liver / Q000469:parasitology / Q000473:pathology; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy*; D013424:Sulfanilamides / Q000627:therapeutic use*
D000980:Antiplatyhelmintic Agents; D013424:Sulfanilamides; C015675:clorsulon