Controlled test evaluation of the benzimidazole anthelmintic VET 220-S alone or with concomitant trichlorfon treatment against naturally acquired gastrointestinal parasites in ponies.

This research evaluates the efficiency of the drug VET 220-S, with or without the addition of trichlorfon, in treating gastrointestinal parasites in ponies. The study demonstrated that all doses of VET 220-S effectively eliminated a range of parasites, with trichlorfon adding effectiveness against another. However, both VET 220-S and trichlorfon were not effective against certain parasites.

Methodology

• The study involved 30 ponies that were naturally infected with gastrointestinal parasites.
• The ponies were divided into five groups for treatment. One group was left untreated, one group was given just VET 220-S, one group just trichlorfon, and two different groups were given combinations of VET 220-S and trichlorfon.
• All drugs were administered by nasogastric intubation, a process involving a tube passed through the nose and down into the stomach.
• The ponies were later euthanized and necropsied seven or eight days after treatment to examine the exact effects of the drugs.

Findings

• VET 220-S, in all doses, effectively treated several forms of parasites including Draschia megastoma, Oxyuris equi, Strongylus vulgaris, S. edentatus, and small strongyles.
• Neither VET 220-S nor trichlorfon were effective in treating for Habronema muscae and microfilariae of Onchocerca cervicalis.
• Trichlorfon was found to be 97.9% effective against Gasterophilus intestinalis.
• Pregnant mares were not adversely affected by treatment, except one mare that had diarrhea after treatment with TCF.
• The findings from analyzing parasite eggs per gram and larval culture data agreed with the results of the necropsies.

Conclusion

• This controlled test suggests that the anthelmintic drug VET 220-S is effective in treating a range of gastrointestinal parasites in ponies. Use of VET 220-S in combination with trichlorfon appeared to increase the range of parasites treated effectively.
• However, further investigation is recommended to explore strategies for handling parasites that were resistant to both drugs.