Evaluation of the myoelectrical activity of the equine ileum infected with Strongylus vulgaris larvae.

The article explores how the invasion of Strongylus vulgaris larvae, a type of horse parasite, affects the electrical activity of the pony’s small intestine (ileum). The study reveals significant changes in the intestine’s myoelectrical patterns after invasion, which could potentially lead to colic, a common equine abdominal pain issue.

Experiment Setup

• The research study included five young ponies. The researchers first implemented a 6-week deworming program on the ponies to ensure they were parasite-free.
• Four Ag-AgCl bipolar electrodes were then surgically infused on the lower part of the small intestine (ileum) in each pony for conducting the study.
• For over 5 days, the ileal myoelectrical activity was recorded for three hours per day under three conditions: pre-inoculation, post-ingestion of 1,000 killed Strongylus vulgaris larvae, and post-ingestion of 1,000 live S vulgaris larvae.

Data Analysis

• The researchers analyzed the recordings in terms of slow wave frequency, distribution of phases I, II, and III of the migrating myoelectrical complex (MMC), and the frequency of distinct action-potential complexes during phase 2 of the MMC.
• Noteworthy changes were observed in both scenarios where the ponies were administered with either killed or live S. vulgaris larvae.
• These changes involved an increase in the number of disrupted phase III complexes, and a significant rise in the number of migrating action-potential complexes.

Results and Interpretation

• Post-inoculation of live 3rd-stage S. vulgaris larvae led to a major increase in the instances when the MMC registered extended periods without any spike activity, also called phase I.
• The substantial alteration in the ileal myoelectrical activity indicates that the intrusion and submucosal movement of S. vulgaris larvae potentially leads to significant changes in the intestinal movement patterns.
• This disturbance in the ileal motility could be a potential cause of colic, a common abdominal discomfort encountered by horses.
• Even the presence of only the antigen of the parasite within the intestinal lumen seems to affect ileal motility.