Figure 6.

Heart sections from a muskellunge (Esox masquinongy) exposed at the medium dose (4 × 10³ plaque forming units mL⁻¹), 28 days post-infection. (a) Severe mononuclear infiltration between necrotic cardiac myocytes. (b) Positive riboprobe staining of myocardium. Note the lack of staining in the endo and pericardial layers. (c) Focally diffuse cardiac myositis. (d) Positive riboprobe staining in cardiac myocytes surrounding the area of inflammation and necrosis (scale bar a,b = 110 µm; c,d = 75 µm).