Which vascular change was reported in the pathology of the diseased fish?

• A. Arteriosclerosis
• B. Atherosclerosis
• C. Vasculitis
• D. Hemangioma

Answer: (A)

Arterial stiffening from thickened vessel walls is a classic vascular change seen in diseased fish. This arteriosclerotic remodeling involves smooth muscle proliferation and increased connective tissue in the tunica media and/or intima, which narrows the lumen and reduces arterial elasticity. The result is impaired blood flow and can contribute to circulatory limitations or ischemic effects in the fish.

Atherosclerosis would imply focal lipid-rich plaques forming in the vessel walls, a pattern more typical of lipid metabolism issues seen in some mammals rather than a general arterial stiffening described here. Vasculitis would present with inflammation of the vessel walls, often with inflammatory cells and wall damage rather than the concentric thickening and loss of elasticity characteristic of arteriosclerosis. Hemangioma is a benign tumor of blood vessels, a localized vascular growth, not a systemic change described as arteriosclerosis.