Controlled tests of activity of ivermectin against natural infections of migratory large strongyles and other internal parasites of equids.

The research was about testing the effectiveness of ivermectin in treating infections of various internal parasites in horses, focusing on large strongyles.

Objective and Methodology

• The research was designed with four controlled tests labelled A, B, C, and D. These tests aimed to evaluate the effectiveness of ivermectin, a known anti-parasitic drug, against various internal parasites in horses. The particular focus was on the action of ivermectin against two types of large strongyles, Strongylus vulgaris and S edentatus, located in different parts of the horses’ body.
• Each experiment involved a small number of horses, most of which were mixed-breed yearlings. In all experiments, the horses were grouped into treated and non-treated, with the treated group receiving ivermectin.
• The treated and non-treated horses were subsequently examined or necropsied after certain intervals, which ranged from 35 to 53 days, depending on the experiment.

Results and Findings

• The treatment with ivermectin proved effective against S edentatus located in the ventral abdominal wall of the horses. In all four experiments, only dead worms or worm fragments were found in the treated horses, while living worms were found in the non-treated ones.
• A similar killing effect was observed against S vulgaris in the cranial mesenteric arteries in two of the experiments (B and D). In these experiments, living S vulgaris worms were found in the non-treated horses, while a single dead worm was found in one of the treated horses in experiment B.
• The research thus concluded that ivermectin was effective in killing the targeted parasites in horses. However, due to the small sample size of the experiments, further research might be necessary for generalizable conclusions.