[2] Megalocytiviruses are an emerging group of closely related dsDNA viruses which cause systemic infections in a wide variety of wild and cultured fresh and saltwater fishes.

[3] Considerable effort has been expended to understand the transmission and epizoology of megalocytiviruses because of the economic importance of commercial fisheries and aquaculture operations.

[2] There is already substantial evidence of this problem: megalocytiviruses which are genetically identical or extremely similar to ISKNV have been isolated from ornamental fishes (gouramis) that were being traded internationally.

[2] Furthermore, an Australian outbreak of megalocytivirus among farmed Murray cod (Maccullochella peelii) was linked to imported gouramis in pet shops.

Clinical signs associated with infection are nonspecific and may include appetite loss, uncoordinated swimming, lethargy, coelomic distention, darkening skin color, petechiae, fin erosion, and death.

[2] The hypertrophied cells are frequently perivascular in distribution and are greatly enlarged due to large granular to foamy basophilic cytoplasmic inclusion bodies.