In vitro evaluation of ivermectin, moxidectin, albendazole and pyrantel against cyathostomins of horses.

The research article focuses on comparing the effectiveness of four deworming drugs – Ivermectin, Moxidectin, Pyrantel, and Albendazole – against a common type of parasitic nematode in horses, Cyathostomins, using an experimental process known as the larval migration on agar test (LMAT). The study identifies Ivermectin and Moxidectin as the most consistent and effective drugs.

Study Objective and Methodology

• The primary objective of the study was to assess the consistency and effectiveness of four drugs – Ivermectin, Moxidectin, Pyrantel, and Albendazole – in combating cyathostomin larvae using the LMAT technique.
• This was carried out across five repetitions of the test for each drug, with the concentrations ranging across eight different values.

Larval Migration on Agar Test (LMAT)

• LMAT is a test used to measure the effectiveness of a drug in killing cyathostomin larvae.
• It involves observing the movement or migration of the larvae in the presence of the drug under study. Reduction in larval migration indicates drug effectiveness.

Results and Findings

• The test showed a strong correlation (R2 > 0.91) between the repetitions, suggesting excellent consistency.
• The average 50% effective concentration (EC50), the concentration at which 50% of the cyathostomins were affected by the drug, was calculated for each drug. Ivermectin and Moxidectin were found to have the lowest EC50, suggesting they were the most effective, followed by Pyrantel and Albendazole.
• The EC50 for Albendazole showed the greatest variation, implying its effectiveness was less consistent compared to the other three drugs. Ivermectin and Moxidectin showed the least variations, making them the most consistent across tests.

Implications and Future Research

• The findings from the study contribute to our understanding of multidrug resistance in cyathostomins and provide a critical comparison between commonly used deworming drugs. Especially, with Ivermectin and Moxidectin proving to be more effective, it can inform treatment decision-making.
• In future, internationally certified susceptible isolates could be used for screening potential drug candidates or detecting any changes in drug efficacy among field populations. Such patterns can aid in dealing with the multidrug resistance issue in cyathostomins.