Anthelmintic efficacy of ivermectin given intramuscularly in horses.

This research article investigates how effectively ivermectin, administered intramuscularly, treats parasitic infections in female horses, finding it highly effective against several parasites and without observed adverse reactions.

Introduction and Methodology

• The study aims to evaluate the anthelmintic activity of ivermectin, a medicine used to treat many types of parasite infections, specifically in female horses.
• The study used 18 female horses, all of which had naturally acquired parasitic infections.
• These horses were treated once via intramuscular injection (IM) with three different methods: six horses received only a vehicle (a substance used to administer the drug), six were treated with 200 micrograms per kilogram of body weight of ivermectin, and a final six were treated with 300 micrograms per kilogram.

Efficacy of Ivermectin

• The researchers analyzed the efficacy or effectiveness of the ivermectin treatment in combating various parasites, comparing the results of both dosages (200 and 300 micrograms/kg).
• Ivermectin proved highly effective against several types of parasites. The efficacy was over 99% against Gasterophilus species, 100% against Trichostrongylus axei, Habronema muscae, H majus, and Draschia megastoma, about 98% to 99% against adult cyathostomes, 86% to 97% against 4th-stage cyathostomes, and 100% against adult large strongyles.

Incomplete Activity and Side Effects

• Despite its high efficacy against most parasites, ivermectin was not fully effective against the arterial stages of the parasite Strongylus vulgaris.
• However, it was effective against the microfilariae (early stage larvae) of the Onchocerca species.
• Importantly, there were no adverse local or systemic reactions observed in the horses due to the treatment with ivermectin, suggesting it is a safe treatment option.