White Sturgeon Iridoviral Disease (WSIV) is a major cause of mortality among farm-raised white sturgeon in North America, Russia, and Europe. WSIV is an epitheliotropic virus, which infects the skin, gills, and upper alimentary tract. Infection of oral mucosa and olfactory organ epithelium causes the fish to stop feeding. This leads to emaciation, which is a principal clinical sign of disease. Transmission routes of WSIV are unknown, however horizontal transmission in water has been demonstrated in hatcheries and laboratory experiments. Diagnostic methods for WSIV include microscopic observation of characteristic infected cells in tissue sections of oral mucosa, gills, and skin. This virus is not transmissable to humans.