Controlled test and clinical evaluation of dienbendazole against naturally acquired gastrointestinal parasites in ponies.
A controlled test was performed to titrate the anthelmintic dosage of dienbendazole in 24 mixed-breed ponies naturally infected with Strongylus vulgaris, S edentatus, and small strongyle species, as determined by parasitic egg and larval counts in feces. Comparison of results of treatment was made among 3 dienbendazole dosages--2.5, 5, and 10 mg/kg of body weight--and a gum (excipient) mixture given by nasogastric intubation. All ponies were euthanatized and necropsied at 7 or 8 days after treatment. Trichostrongylus axei, Habronema muscae, S vulgaris, S edentatus, small strongyles, and Oxyuris equi were efficaciously eliminated in response to all doses of dienbendazole; Gasterophilus spp were not affected by any dose. There were not sufficient numbers of Draschia megastoma, Anoplocephala spp, or Parascaris equorum in the ponies to evaluate drug effect. Changes in the appearance of the intestinal lining were dose-dependent; in the ponies treated with 5 and 10 mg of dienbendazole/kg, the mucosa appeared clean and smooth, though in ponies given 2.5 mg/kg, it appeared clean, but was nodular and moderately reactive to embedded immature small strongyles. In the gum mixture-treated ponies, the large intestinal mucosa was inflamed, with edematous areas, in response to infections caused by large and small strongyles. A limited clinical titration was done in 12 ponies that were fecal culture negative for S vulgaris larvae, although other strongyles were detected. Two ponies in each of 6 groups were given the following dosages: 0 (gum mixture only), 0.5, 1, 2.5, and 5 mg of dienbendazole/kg. One group of 2 ponies was given 5 mg of fenbendazole/kg as a standard treatment control.(ABSTRACT TRUNCATED AT 250 WORDS)
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Sandhill Equine Center, Southern Pines, NC 28387.
D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology / Q000627:therapeutic use*; D001562:Benzimidazoles / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary*; D007413:Intestinal Mucosa / Q000187:drug effects; D008297:Male
D000871:Anthelmintics; D001562:Benzimidazoles; C062729:dienbendazole