Figures 1–4.

Microscopic changes of Streptococcus equi subsp. zooepidemicus septicemia in a feeder pig and sow. Figure 1. Acute suppurative nephritis of a feeder pig from the Ohio buying station, comprised of mostly neutrophils and fewer macrophages, with scattered karyorrhectic and karyolytic cellular debris admixed with scant fibrin. Note the large colonies of bacteria (arrows) within the inflammatory focus. H&E. 400×. Figure 2. Cardiac muscle of the feeder pig is effaced by similar suppurative inflammatory infiltrates with degeneration and necrosis of cardiac myofibers. H&E. 200×. Figure 3. The spleen from sow 3 from the Tennessee abattoir is covered by fibrinosuppurative exudate characterized by aggregates of degenerate neutrophils and necrotic cellular debris admixed with fibrin. H&E. 200×. Figure 4. Intracellular and extracellular gram-positive, paired cocci (arrows) are scattered within the fibrinous exudate on the splenic capsule; sow 3. Gram. 1,000×.