Viral Nature of Piscine Erythrocytic Necrosis (PEN) in the Blood of Atlantic Cod (<i>Gadus morhua</i>)

Abstract

Piscine erythrocytic necrosis (PEN), a degenerative disease of erythrocytes of Atlantic cod (Gadus morhua), is described at the electron microscope level and compared with light microscope findings. PEN infection is found associated with a cytoplasmic pool of hexagonal particles reminiscent of large icosahedral cytoplasmic deoxyriboviruses (ICDV). Fibrillar strands appear associated with the infection. PEN is compared with other possible ICDV infections in various poikilotherm vertebrates and is considered to be included in a distinct ICDV subgroup which also contains virions associated with infections of Pirhemocyton, Toddia, rock blenny infections, and perhaps lymphocystis.