Controlled test and clinical evaluation of dienbendazole against naturally acquired gastrointestinal parasites in ponies.

The study seeks to understand the effectiveness of varying dosages of the anthelmintic drug dienbendazole on ponies naturally infected with certain gastrointestinal parasites. The primary goal of the study was to identify the optimal dosage for eliminating these parasites while minimizing side-effects, specifically changes in the appearance of the horses’ intestinal lining.

Research Methodology

• The researchers conducted a controlled test on 24 mixed-breed ponies naturally infected with various parasites as determined by parasitic egg and larval counts in their feces.
• Three different dienbendazole dosages were tested: 2.5, 5, and 10 mg/kg of body weight. A control group was given a gum mixture (excipient) via nasogastric intubation.
• All ponies were euthanized and necropsied 7 or 8 days after treatment to assess the effects of the drug on the parasites and the condition of the intestinal lining.

Research Findings

• The anthelmintic drug dienbendazole successfully eliminated various types of parasites across all dosage levels.
• However, the drug didn’t affect Gasterophilus spp, and there weren’t enough Draschia megastoma, Anoplocephala spp, or Parascaris equorum present in the ponies to evaluate the drug’s effect on such parasites.
• Treatment with dienbendazole also led to dose-dependent changes in the intestinal lining. The highest doses (5 and 10 mg/kg) resulted in a clean and smooth mucosa. The lowest dose (2.5 mg/kg), although effectively cleaning the mucosa, led to a nodular and moderately reactive response to the presence of immature small strongyles.
• In contrast, the control group showed inflamed and edematous regions in the large intestinal mucosa resulting from parasite infection.

Limited Clinical Titration

• Additionally, a limited clinical titration was conducted on 12 ponies that tested negative for certain parasites. These ponies were given varying dosages of dienbendazole, including a control group given a standard anthelmintic compound. However, the abstract does not provide the results of this clinical titration.

Conclusion

• The study proved that dienbendazole is efficacious against a range of parasites in ponies at a range of dosages, although the reaction of the intestinal lining to the drug was dose-dependent. The effect of the drug on Draschia megastoma, Anoplocephala spp, or Parascaris equorum parasites remains unknown due to their insufficient population in the sample groups.