Identification of strongyle eggs from anthelmintic-treated horses using a PCR-ELISA based on intergenic DNA sequences

Area of Science:

• Veterinary Parasitology
• Equine Health
• Anthelmintic Resistance

Background:

• Benzimidazole-resistant cyathostomins pose a significant threat to equine health.
• Effective control strategies for these resistant parasites are urgently needed.

Purpose of the Study:

• To evaluate the efficacy of a five-day fenbendazole (FBZ) treatment against benzimidazole-resistant cyathostomins in horses.
• To monitor the re-emergence of cyathostomin infections post-treatment.

Main Methods:

• Horses (n=13) received pyrantel embonate followed by a five-day course of FBZ.
• Faecal egg counts were used to assess treatment efficacy.
• PCR-ELISA identified six cyathostomin species pre- and post-treatment.

Main Results:

• Pyrantel embonate achieved 98% faecal egg count reduction.
• All horses were negative for faecal eggs 7 days after FBZ treatment.
• Positive egg counts reappeared by 28 days, with all horses positive by 77 days.
• Cyathostomum catinatum and Cylicostephanus longibursatus were the most prevalent species post-treatment.

Conclusions:

• A five-day fenbendazole treatment offers only transient efficacy against benzimidazole-resistant cyathostomins.
• Parasite populations rapidly re-established post-treatment, indicating resistance.
• Further research into alternative anthelmintics and resistance management is crucial for equine parasite control.