Disease | Causative Agent | Susceptible Species | Clinical Signs and Pathology | Temperature Range | Status in US |
---|---|---|---|---|---|
Viral hemorrhagic septicemia (Egtved disease) | Novirhabdovirus Family: Rhabdoviridae | Primary: salmonids (Oncorhynchus spp), turbo, herring and spat (Clupea spp), Japanese flounder Secondary: grayling, whitefish, pike, Atlantic and Pacific cod, haddock, and many freshwater, marine, and estuarine species | Acute form: nonspecific hemorrhaging (eyes, fins, or skin), darkening, exophthalmia, ascites Chronic form: few signs Neurologic form: spinning or flashing Gross: enlarged spleen, ascites, necrotic kidney Histologic: focal necrosis of kidney liver, spleen; hemorrhage in muscle | 48°–54°F (9°–12°C) optimal | Present in wild populations, sporadic, limited distribution; endemic in Pacific Northwest and Alaska (wild salmonids, haddock, and cod); emerging disease in Great Lakes region in a wide variety of fishes. |
Infectious hematopoietic necrosis | Novirhabdovirus Family: Rhabdoviridae | Primary: cultured salmonids (Oncorhynchus spp); lake trout and char (Salvelinus spp) are resistant | Rapidly increasing mortality (fish < 1 year), lethargic but sporadic bursts of rapid swimming occur, protruding vent, fecal casts, exophthalmic, pale gills, darkening, abdominal distention or ascitic fluid (possibly bloody) | 50°–54°F (10°–12°C) optimal; rare >15°C (59°F) | Present in western US, sporadic, limited distribution; endemic in Pacific Northwest and Alaska (wild salmonids); also present in parts of Europe and Asia |
Spring viremia of carp | Vesiculovirus Family: Rhabdoviridae | Primary: carp (including koi, goldfish), sheatfish (European catfish), orfe, tench | Nonspecific: darkening, exophthalmic, pale gills, distended abdomen, ascites, hemorrhage (gills, skin, or eye), petechiae in organs (including swim bladder), protruding vent with thick mucoid fecal cast Coinfection with Aeromonas or other bacteria common | 54°–72°F (12°–22°C) | US is free (last occurred in captive fish in 2004, wild fish in 2007); occurs in eastern Europe, Russia, China, and Middle East |
Epizootic hematopoietic necrosis | Ranavirus Family: Iridoviridae | Primary: redfin perch Secondary: rainbow trout (wild and farmed fish) | Acute and high mortality of redfin perch; darkening, ataxia, lethargy, hemorrhage around nares; morbidity and mortality of rainbow trout less severe; Histologic: necrosis, renal hematopoietic tissues | Redfin perch: 54°F (>12°C) Rainbow trout: 52°–63°F (11°–17°C) Experimental: 46°–70°F (8°–21°C) | Has never occurred in US; endemic in Australia Endemic in Australia |
Red sea bream iridoviral disease | Megalocytivirus Family: Iridoviridae | Red sea bream, many other estuarine species, other marine species | Severe anemia, lethargic, pale gills, enlarged spleen | Has occurred in imported tropical marine fish in US; occurs in Japan and Taiwan | |
Infection with HPR-deleted or HPR0 Infectious salmon anemia | Isavirus Family: Orthomyxoviridae | Atlantic salmon Brown trout, sea trout, rainbow trout | Pale gills, severe anemia (PCV < 10%), swollen liver (black or brown color), ascites, petechiae of viscera, mesenteric fat, swim bladder | In vitro: Maximum replication 59°F (15°C) No replication 77°F (25°C) | Present in northeast US, sporadic, limited distribution; endemic in Maine, New Brunswick, Scotland, and Norway Endemic in Maine, New Brunswick, Scotland, and Norway |
Infection with salmonid alphavirus (pancreas disease or sleeping disease) | Alphavirus Family: Togaviridae | Atlantic salmon, rainbow trout, brown trout | Necrosis of exocrine pancreas, heart and skeletal muscle changes | 54°–59°F (12°–15°C) | Has not occurred in US; detected in Ireland, UK, France, Germany, Italy, Spain, Switzerland, Poland, and Norway |
Koi herpesvirus | Cyprinid herpesvirus-3 Family: Alloherpesviridae | Common carp and hybrids, including koi and ghost carp | Severe necrosis gill tissue | 72°–78°F (22°–25.5°C) optimal* | Present in US, sporadic, widely distributed |
Epizootic ulcerative syndrome (mycotic granulomatosis) | Aphanomyces invadans Oomycetes (water mold) | Atlantic menhaden, striped mullet, many other freshwater and estuarine species; snakeheads, barbs (Puntias spp) sensitive; gouramis, goldfish and other ornamentals susceptible; tilapia resistant | Necrotizing deep ulcers (penetrate body wall), granulomatous tissue response; deep ulcers with red centers, white rims; invasive nonseptate hyphae (culture possible but difficult) | 77°F (< 25°C) (reduced salinity also contributes in brackish systems) | Present in US, sporadic, limited distribution; reported in North America, Africa, Asia, and Australia |
Gyrodactylus (Gyrodactylus salaris only) | Monogenea Gyrodactylus salaris only | Atlantic salmon, rainbow trout, brook trout, North American lake trout, brown trout, grayling arctic char | Has never occurred in US | ||
*Mortalities stop at 86°F ( >30°C) , but survivors remain carriers. |