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 3

Brain histopathology of moribund B. tyrannus with V. anguillarum. (a) Optic tectum with congestion and hemorrhage within the stratum periventriculare layer and dilated blood vessels with perivascular fibrin deposition. Bar = 500 µm. (b) Hemorrhagic encephalitis containing mainly eosinophilic granule cells. Bar = 50 µm. (c) Hindbrain with cell degeneration and hemorrhage. Red blood cells and degenerated cells have sloughed into the fourth ventricle (). Bar = 50 µm. (d) Hemorrhagic meningitis; inset shows large numbers of eosinophilic granule cells. Bar = 100 µm; inset bar = 25 µm. (e) Hindbrain with hemorrhage and massive amounts of bacteria surrounding a blood vessel (). Bar = 20 µm.