Ultrastructure of Lymphocystis in the Heart of the Silver Perch, Bairdiella chrysura (Lacépède), Including Observations on Normal Heart Structure

Abstract

The fine structure of normal heart muscle from the silver perch, Bairdiella chrysum (Lacdp\ede), is similar to that previously reported for marine and freshwater teleosts. Cardiac lymphocystis is a viral disease manifested by single, giant-cell lesions variously located in the epicardium, trabecular spaces, and subendocardium-in direct apposition to myocardial cells. Occasionally, the hyaline capsule of lymphocystis cells partially surround myocardial cells but cause no pathological changes or inflammatory reaction. The lymphocystis cells contain typical cellular organelles, including the viroplasmic net unique to these cells. Annulate lamellae, often continuous with the rough endoplasmic reticulum, are present, usually along the periphery of the cell. Some elements of the rough endoplasmic reticulum are dilated and contain a finely granular material, but others contain cross-banded fibrils, each having a periodicity of 30 nm. Similar fibrils are present in the perinuclear cisternae.