Strongylus vulgaris Induced aneurysm of mesentric artery complicated with ileal volvulus in a horse

An eight-year-old gelding presented with signs of colic to the Madras Veterinary College Hospital and treated for the same but collapsed and sent to the Department of Veterinary Pathology for post mortem examination. On necropsy examination cranial mesenteric artery found to be dilated and thin walled and on incision thrombus occluding the lumen along with live strongyle worms observed. Multiple varying sized nodules with round worms also noticed. Ileal volvulus involving 180O rotation of ileum about its mesentery and encircling the caecum also observed. On histopathological examination of the artery strongyle worms found in the lumen along with presence of abundant collagen fibers and small aggregates of smooth muscle cells. Mononuclear cell infiltration also noticed in the intimal and medial layer of the cranial mesenteric artery. Thrombus occluding the lumen of the artery were evident on microscopic examination. Based on necropsy and microscopic examination the case was diagnosed as verminous aneurysm complicated with ileal volvulus.