Ninety-one equine aortic and cranial mesenteric arterial segments were evaluated ultrasonographically in a water bath. On the basis of pathologic evidence of verminous arteritis, arterial segments were classified into 4 categories, and the ultrasonographic characteristics of each group were evaluated. Normal arteries (class 1) were ultrasonographically characterized by a smooth luminal surface layer and uniform wall thickness and echogenicity. Arteries with only histopathologic evidence of verminous arteritis (class 2) were ultrasonographically characterized by a smooth luminal surface layer, uniform thickness, uniform echogenicity, and the presence of a hyperechoic luminal layer. Arteries with both gross and histopathologic evidence of verminous arterities (class 3) were characterized ultrasonographically by an irregular luminal surface layer, varying wall thickness, varying wall echogenicity, and the presence of a hyperechoic luminal layer. The ultrasonographic characteristics of arteries with luminal thrombosis (class 4) were an irregular luminal surface, varying wall thickness, and nonuniform echogenicity.

Strongylus vulgaris, ponies (exper.), diethylcarbamazine did not prevent clinical or pathological changes due to migrating larvae, fewer adults recovered at necropsy from treated vs. untreated ponies

techniques to locate lesions and recover developmental stages of helminths from equine arteries, subperitoneum, liver, and lungs postmortem

Semiselective mesenteric arteriography was performed at regular intervals (inoculation weeks [IW] 0, 18, and 24) in 9 of 10 pony foals raised to be free of parasites. Fifty infective larvae (L3) of Strongylus vulgaris were administered weekly for 4 weeks, then every 2 weeks through the 20th week. Three ponies were given ivermectin (oral paste, 0.2 mg/kg of body weight) treatment at IW 8, 16, and 24. Four ponies were inoculated, but did not receive ivermectin, and a third group of 2 ponies acted as uninoculated controls. Control ponies did not have gross or arteriographic lesions, whereas the inoculated untreated ponies had gross and progressive arteriographic lesions typical of verminous arteritis. Arteriographic lesions in the ivermectin-treated inoculated ponies were not as severe those in the untreated inoculated group, and there was either a partial resolution or a lack of progression of arteriographic lesions in all treated ponies. One untreated inoculated pony did not have progressive arterial lesions as did the 3 others in the group, and may develop resistance to the parasite.

helminths of Thoroughbred horses with emphasis on stomach worms and tapeworms, numbers and infection rates according to host age and month of necropsy

Strongylus vulgaris, pony foals (nat. and exper.), effectiveness of fenbendazole against later fourth stage larvae assessed by larval motility and studies of cranial mesenteric, ileocolic, and celiac arteries

Strongylus spp. and other parasites of equids (natural infections), controlled tests with fenbendazole in multiple doses at two dose levels

nematodes of ponies, efficacy of oxibendazole in paste formulation, 1-group critical test compared with 2-group control test

Strongylus vulgaris, massive infections of nonimmune and immune ponies, pathogenesis characterized, blood chemical and peritoneal fluid values as possible diagnostic aids

Strongylus vulgaris (larvae), Trichostrongylus axei (adults), ponies (exper.), efficacy of ivermectin, controlled tests