Erythrocytic Necrosis Virus (ENV) - MMFS

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Fish Virus

Erythrocytic Necrosis Virus (ENV)

Pale gills of a herring with VEN

Pale gills of a herring with VEN (top) compared to those of an uninfected, healthy herring (bottom). Credit: Paul Hershberger, USGS - Western Fisheries Research Center. (Public domain)

Viral erythrocytic necrosis (VEN) is a condition characterized by the presence of viroplasmic inclusion bodies within the cytoplasm of affected erythrocytes. The condition is cause by a putative iridovirus, referred to as erythrocytic necrosis virus (ENV). In the eastern North Pacific, VEN frequently occurs in Pacific herring, and it has been associated with recurring epizootics among wild herring in Alaska and Washington. These epizootics can occur over the period of several months and can be geographically localized events among cohorts of juvenile herring.  The disease can cause severe anemia, characterized by pale gills and lethargy, in affected fishes.