Strongyle infections in ponies. I. Response to intermittent thiabendazole treatments.

The study examines the efficacy of thiabendazole in treating ponies naturally infected with large numbers of small strongyles over a three-year period. The results showed that while the treatment was effective at eliminating worms, reinfection occurred, suggesting that regular deworming is necessary.

Methodology

• The researchers enlisted seven ponies that were naturally infected with a significant quantity of small strongyles. They were able to ensure the conditions minimized the chance of reinfection.
• The ponies underwent repeated treatment with thiabendazole at a rate of 44 mg/kg body weight over a continuous span of three years.

Findings

• It was observed that the absence of worm eggs in the pony feces signified the removal of the adult strongyles from the system with each round of treatment.
• However, the adult worm population would be replenished over time as inhibited larvae matured.
• Elimination or significant reduction of the worm infestation required four to five treatment sessions.
• Worm eggs began to reappear in the feces approximately six weeks following each treatment.
• Though the mean egg counts increased following the first treatment reaching almost to pretreatment levels, it was noticed that with successive treatments, the interval for worm eggs to manifest in the feces lengthened and the mean egg counts never reached the immediate pretreatment levels.

Hematological Changes

• In addition to parasitological effects, the study also indicates minor hematological changes in the ponies, including a steady but small increase in mean hemoglobin values, and a commensurate decrease in mean eosinophil counts after each treatment round.

Conclusion

• The study validates the concept of regular deworming treatment for horses. As it shows, the absence of reinfection does not prevent a new wave of adult worm burdens from developing after treatment.