Seasonal Mortality of Wild Atlantic Menhaden (Brevoortia tyrannus) Is Caused by a Virulent Clone of Vibrio (Listonella) anguillarum; Implications for Biosecurity along the Atlantic Coastal United States

Figure 4

Histopathology in the internal organs of moribund B. tyrannus with V. anguillarum. (a) Severe degeneration of hematopoietic cells in the kidney. Bar = 50 µm. (b) Higher magnification of pyknotic and degenerated hematopoietic cells in the kidney. Bar = 20 µm. (c) Kidney with severe infiltration of eosinophilic granule cells and degenerated hematopoietic cells. Bar = 50 µm. (d) Higher magnification of eosinophilic granule cells, some of which appear degranulated, and hematopoietic cells that are enlarged and have pyknotic nuclei. Bar = 20 µm. (e) Spleen with severe degeneration of leukocytes. Bar = 50 µm. (f) Liver with an inflammatory infiltrate, predominantly eosinophilic granule cells, surrounding a blood vessel. Bar = 50 µm. (g) Liver perivascular inflammatory infiltrate with degenerative changes, including swelling and pyknosis. Bar = 50 µm.