Evaluation of ivermectin for larvicidal effect in experimentally induced Parascaris equorum infections in pony foals.

The research covers the effectiveness of ivermectin in controlling the infestation of Parascaris equorum, a parasitic worm in pony foals. It shows that both liquid and paste forms of ivermectin administered at a specific dosage eradicated the parasite larvae with no side-effects observed.

Study Design and Implementation

• The study was conducted on 15 pony foals which were intentionally infected with an average of 1500 Parascaris equorum eggs each.
• The foals were divided into three groups- two were treated with ivermectin (one with a paste formulation, the other with a liquid formulation, both at a dose of 0.2mg per kg body weight), while the third group was left untreated as a control.
• The ivermectin treatments were administered on the 11th day after the purposeful inoculation of the parasite eggs.

Assessment and Findings

• The foals were euthanized on the 25th day after the inoculation for a detailed examination of larvae presence in their small intestine, lungs, and liver.
• Both groups of foals that were treated with ivermectin (liquid or paste) were found to be free from the parasite larvae.
• In contrast, the untreated control group had a significantly higher average number of 4th stage larvae (approximately 960.9 per foal, ranging from 379 to 1736).
• Regardless of the treatment, all the foals exhibited similar levels of pathologic changes in their lungs and livers, implying that these changes were caused by the parasitic migration itself and not the treatment.

Conclusions

• The study demonstrates the efficacy of ivermectin, in both its paste and liquid forms, in controlling Parascaris equorum infections in pony foals by eliminating the larvae.
• No adverse reactions to the treatment with ivermectin were observed, suggesting its safety for use.