Degeneration of capillary endothelial cells in M. suis -infected pigs. Representative small intestinal venule of an M. suis-infected pig (histological analysis). Massive cytoplasmic swelling of ECs, accompanied by progressive cellular necrosis and detachment of ECs from the underlying basement membrane, is evident. Arrowheads indicate areas of cellular denudation of the luminal surface; Arrows indicate immunoreactive M. suis cells. Scale bar = 20 μm.