Critical tests in equids with fenbendazole alone or combined with piperazine: particular reference to activity on benzimidazole-resistant small strongyles.

The research carried out tests on fenbendazole, a medication used for treating parasitic worm infections, to evaluate its effectiveness when administered alone or in combination with piperazine, another anti-parasitic drug. The study emphasized on its activities against small strongyles-resistant to benzimidazole, another class of anti-parasitic drugs, with results showing varying levels of efficiency in the removal of the resistant parasites.

Study Process

• The research team conducted seven critical tests in equids (horses and ponies) using single doses of fenbendazole, either alone or combined with piperazine. They used two different forms: paste and suspension.
• The primary objective was to evaluate the activity of these treatments against small strongyles resistant to benzimidazole, a common anti-parasitic medication-represented by five species (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus).
• The researchers examined natural infections in two different strongyle populations referred to as population B (in two horses) and population S (in five ponies).

Results of the study

• For the horses (population B) treated with fenbendazole paste alone, the removal of the five identified species was between 49-91%. However, the animal treated with the combination of drugs achieved a 100% removal for four out of the five species.
• For the ponies (population S), one animal treated with fenbendazole paste alone had two of the five resistant species which were completely removed while a pony treated also with fenbendazole but as a suspension, yielded a removal rate of 0-70% for the five benzimidazole-resistant species.
• The treatment was also evaluated for removing other parasitic worms such as large strongyles (Strongylus vulgaris and Strongylus edentatus) and Oxyuris equi, in which it achieved a removal rate of 92-100%.

Insights and Conclusion

• The study indicated that fenbendazole, both in its solo administration and in combination with piperazine, showed no activity against bots, tapeworms, and the parenteral stages of Strongylus vulgaris and Strongylus edentatus.
• The combination treatment might have demonstrated some activity against immature Habronema species and mature abronema muscae.
• The research suggests that the combination of fenbendazole and piperazine displayed superiority over fenbendazole alone for the treatment of benzimidazole-resistant small strongyles. However, not all parasite species responded to the combination treatment, which indicates a need for further investigation and more versatile anti-parasitic treatments.