Sequential mesenteric arteriography in pony foals during repeated inoculations of Strongylus vulgaris and treatments with ivermectin.

The research aims to study the effects of repeated inoculations of Strongylus vulgaris larvae on pony foals, and the effects of ivermectin treatment on these arteriographic lesions. The control group remained healthy, the untreated inoculated group developed significant arteritis, and the ivermectin-treated group revealed milder symptoms and no sign of worsening arteriographic conditions.

Study Design and Participants

• The study involved a total of 10 pony foals, all raised to be parasite-free.
• The ponies were divided into three groups: Three ponies received ivermectin treatment, four pony foals were only inoculated with Strongylus vulgaris larvae, and two ponies acted as uninoculated controls.

Process of Inoculation and Treatment

• Semi-selective mesenteric arteriography, an imaging test used to view the arteries in the abdomen, was performed regularly at defined periods (every 7 to 13 weeks).
• The inoculated groups received fifty infective larvae of Strongylus vulgaris. They were administered weekly for one month and then every two weeks through the 20th week.
• The ivermectin-treated group received an oral paste (0.2mg/kg of body weight) treatment at three separate intervals — at 8th, 16th and 24th week.

Findings and Observations

• The control group of ponies, which wasn’t inoculated with the larvae, did not show any signs of arteriographic lesions or gross abnormalities, asserting their healthy state.
• The untreated inoculated group displayed distinctive arteriographic lesions and clear signs of verminous arteritis, a disease caused by parasitic worms.
• Theponies treated with ivermectin showed less severe arteriographic symptoms compared to the untreated inoculated group. Further, there was either a partial resolution or a lack of progression of arteriographic lesions in all treated ponies, indicating the positive effect of ivermectin treatment.
• Interestingly, one pony in the untreated inoculated group did not follow the expected trend. Unlike the others in its group, it did not develop progressive arterial lesions, suggesting a likely natural resistance to the parasite.