Exotics - Fish 3

pbhati17's version from 2017-03-08 23:17

Viral Dzs!!

Question Answer
*What was the 1st viral dz described/recovered from fish. Czs necrosis of pancreatic acinar cells & mesenteric fat & enteritis. What do you expect to see in the pyloric cecae?Infectious Pancreatic Necrosis (IPN), expect brightly eosinophilic protein casts in pyloric cecae
**What virus is primarily a dz of restocking hatcheries that czs acute necrosis of all cell types in renal intersitium/portal endothelium/tubules & spleen → later, pancreas/liver.Infectious Hematopoietic Necrosis (IHN)
*What type of virus is Infectious Hepatic Necrosis? What zoonotic dz is in this family?Rhabdovirus, rabies is also a Rhabdovirus
*What is usually a ↓ temperature dz & can lead to 100% mortality in young trout seen in the great lakes region of the US & in Europe. Lesions incld necrosis of renal interstitium, hemorrhage in muscle, choroid gland of eye & gills → hemosiderin accumulation.Viral Hemorrhagic Septicemia (VHS), aka Egtved dz, also a Rhabdovirus
What 1⁰ lesion do you think of w/ rhabdoviruses?Hemorrhage
*What is a reportable dz in the US & commonly affects carp in the spring when water temperatures are low? Signs incld hemorrhage to incld the eye → exopthalmia, necrotic enteritis.Spring Viremia of Carp (SVC), czd by Rhabdovirus carpio
*Name 3 notifiable dzs of fish czd by Rhabdoviruses?(1) IHN - Infectious Hematopoeitic Necrosis
(2) VHS - Viral Hemorrhagic Syndrome
(3) SVC - Spring Viremia of Carp
*What virus affects trout <6 mos of age w/ 50-100% mortality? Syncytia (multinucleate cells) in pancreatic acinar tissue are pathognomonic for this dzHerpesvirus salmonis
*What virus czs plaque-like epidermal hyperplasia in carp? What kind of virus is this?Carp pox czd by Herpesvirus!!
*What orthomyxovirus czs hepatocellular necrosis & anemia, plus renal tubular necrosis.Infectious Salmon Anemia Virus (ISAV)
*What is a variant on Infectious Salmon Anemia that affects the kidney?Hemorrhagic Kidney Dz
*What is a recently emerging problem of cultured carp & koi, w/ major lesions in gills & skin. inclusion bodies seen. What other dz is it often seen w/?Koi herpesvirus, often seen w/ Columnaris dz
*What dz other than Koi Herpesvirus are we concerned w/ in koi fish?Costia (aka Ichthyobodo necator, see protozoal dz)
*If you see large cells/cytomegaly, what family of infectious agents do you think of?Viruses!


Question Answer
*What virus replicates in dermal fibroblasts of higher fish czing extreme cytomegaly? Not usually a fatal dz, but easily spread & looks bad. Common in aquarium & wild fish.Lymphocystis, an Iridovirus
*What family of viruses can cz systemic infxn & severe mortality? Which 1 effects cichlids? Infected cells are easily recognized bc they show cytomegaly & often blue/purple inclusionsIridoviruses
Cichlids: orange chromide cichlid iridovirus
*What dz (not to be confused w/ infectious pancreatic necrosis) is an infxn of farmed atlantic salmon in seacages. Produces necrosis & loss of exocrine pancreas w/ rhabdomyopathy (heart, skeletal m., esophagus). This dz is associated w/ ↓ levels of what vitamin?Pancreas dz, associated w/ ↓ levels of Vit E leading to oxidative dmg
*What is the equivalent of this Pancreas dz in freshwater? What fish are effected? What part of the body does this dz target?Sleeping dz of rainbow trout . Targets red muscle fibers, fish can’t maintain water position, have trouble breathing & die quickly
What are the other 2 major differentials for pancreas dz?Heart & skeletal muscle inflammation (HSMI), Cardiomyopathy Syndrome of Salmon (CMS)
***This family of viruses is the cz of Viral Encephalopathy & Retinopathy (VER), czing vacuolar degeneration of brain & retina. Gross changes are pigmentation & abnormal swimming. What organ will give you the most definitive diagnosis?Nodaviruses. Dx in the retina
*This dz is a tumor in the swimbladdar of Atlantic salmon?Atlantic Salmon Swimbladder Leiomyosarcoma
*These are creamy white tumors found anywhere in the body?Lymphosarcoma of pike/muskellunge
*These are severe disfiguring fibrosarcomas in wild walleye. What type of virus are these possibly associated w/?Walleye Dermal Fibrosarcoma, possibly associated w/ Retrovirus
What are diffuse plaques of epidermal hyperplasia seen in young fish, that quickly clear up?Atlantic Salmon Papillomatosis
*This is the major differential for pancreas dz & cardiomyopathy syndrome in Atlantic salmon. Czs marked necrosis of spongy fibers. Dr. Ferguson saw heart regeneration w/ this one!! Sexy. What virus is it associated w/? How do you tell the difference between it & the others?Heart & skeletal muscle inflammation (HSMI), associated w/ a Reovirus. HSMI has heart & skeletal muscle involvement like pancreas dz, but no pancreatic lesions
What syndrome of salmon is czd by the same viral group that cz myonecrosis in shrimp? How do you differentiate it from HSMI & pancreas dz?Cardiomyopathy Syndrome of Salmon (CSS). Heart involvement like HSMI & pancreas dz, but no skeletal muscle involvement like HSMI & no pancreatic involvement like pancreas dz
What agents proliferate w/in cells & can lead to hyperplasia & death esp. in carp in the winter? “Epitheliocystis” or “mucophilosis” czd by chlamydia
What leads to severe granulomatous inflammation in Salmonids/Bass as well as CNS lesions? What virus do they need to be differentiated from?Rickettsia
Need to be differentiated from Nodaviral infxns

Protozoal Dzs!!

Question Answer
*What dz is common in many freshwater fish & produces white spots that can be seen w/ the naked eye?“Ich” or “White Spot” czd by Ichtyophthirius multifilis
**What is the characteristic feature of Ichtyophthirius multifilis? What is the pathology of the dz?Characteristic horseshoe-shaped macronucleus, dark brown granular cytoplasm
Pathology: organism invades epithelium, can cz a break in osmotic integrity of tissue. Severity depends on if basement membrane is reached. If yes, severe inflammation/necrosis can occur
*What dz is found in saltwater, although the parasite is from freshwater & has a jerky spiralling motion on wet smears? (Found on skin beneath the operculum/around dorsal fin & gills.) What fish in particular does this affect that we care about for the test?Ichthyobodo necator (formerly costia). 2nd most important dz in koi behind koi herpesvirus
How does the organism infect the cells?Attaches by means of cystostome which injects into host cell like a hypodermic needle
*What organisms are commensals & do not harm fish?Colonial peretrichs
What organisms are responsible for red tides? What are the dangers of red tides?Dinoflagellates (amyloodinium, crepidoodinium, ichthyodinium). Consume oxygen, some produce toxins
What is the free-swimming form of Dinoflagellates called? Which form attaches? What might these organisms also have?Dinospore free swimming, Trophont attaches
May have chloroplasts
Which specific dinoflagellate czs “velvet dz”, which is a major problem in marine aquaria & fish farms? (Affects gills & sometimes skin, see hyperplasia/necrosis)Amyloodinium oellatum
What organism opposes itself to host cell surface rather than penetrating, has chloroplasts & is less dmging than A. ocellatum?C. cyprinodontum
**What is the cz of “Nodular Gill Dz”? Describe the dz.Amoebae. Severe epithelial proliferations often obliterating entire arches
What organisms are found on skin, gills & GI tract & cz granulomas possibly in combination w/ “Cichlid Bloat” (clostridium hastiforme)?Cryptobia
What specific organism is endemic in wild fish populations, czs anemia, exopthalmia, multifocal necrosis in spleen, kidney & liver plus arteritis?Crytptobia (trypanoplasma) salmonsitica
What dz shows proliferation (merogony) in leukocytes/RBC’s of host, czing a severe multifocal nodular granulomas, anemia & monocytosis?Haemogregarines (ex. h. bigemina, not host specific)

GI Tract

Question Answer
*What agent infects pyloric caeca/intestine of young farmed Salmonids, as well as captive Siamese fighting fish & Angel fish? CS are exopthalmia, distended abdomen, lethargic, spiraling in water. Proteinaceous casts seen, as well as severe multifocal Bilateral & Symmetrical Ulcerative Dermatitis.Hexamita/Spironucleus
What is crucial to dx of Hexamita/Spironucleus? Where will you see the parasite/what does it look like? What is this dz also commonly associated w/?Need to do a whole mount, easy to miss. Parasites closely apposed to brush border, show “blebbing” of mucosa. Often associated w/ bacterial dz → granulomatous peritonitis
These are common organisms that can produce diffuse or nodular lesions. These can infect fish & birds & may use intermediate hosts like crustaceans.“Nodular coccidiosis”, czd by coccidian (inclds eimeria, cryptosporidiae)
*What is the difference between the histozoic & coelozoic types of myxozoa? Which type is more dmging?Histozoic: W/in tissue, more dmging
Coelozoic: W/in cavities/lumens (ie urinary tract or bile ducts
What is the major finding w/ the histozoic type? What species is often effected?Kudoa, marine species affected. Dz czs muscle fibres to be replaced by spores & when parasites are killed they release proetolytic enzymes that liquefy uninfected muscles
*What czs Whirling Dz of trout. What is the intermediate host?Myxobolus cerebralis
Intermediate host: Tubifex (worm)
*What are the lesions of Whirling Dz? What age of fish are much less susceptible? Why? Where are the spores? How can you protect your fish?Cartilage of head/spine invaded by parasites → whirling/spinal deformities. Spores are extracellular. Fish > 6 months are much less susceptible bc of ossification of cartilage (infected but don’t get dz). Protect young fish by raising in concrete ponds, bc avoid contact w/ tubifex intermediate host
*What gram (+), acid fast, intracellular parasites have an extremely wide host range?Microsporidia (so spores are intracellular compared w/ Whirling dz which is extracellualr)
What species of microsporidia czs “Neon Tetra Dz”?Pleistophora hyphenessobryconis
*Which parasites have no intermediate host, are ectoparasites of skin/gills/fins & feed on mucus/ epithelium/blood.Monogenea (flukes)
Phylum: Platyhelminthes
What are the most common monogeneans in freshwater fish & have an undivided haptor w/o paired suckers/ clamps on haptor?Gyrodactylida, dactylogyrida
What is the most significant feature of gyrodactylids that enables fish to reproduce extremely quickly underfavorable conditions?Viviparous!
What actually dmgs the fish?Feeding activity (anterior end) by attachment process of hooks (posterior end)
*Which parasites can be found as both adult & larval (metacercarial) stages in fish? Can be zoonotic. ***What is the most dmging stage?Digeneans, larval stage is most dangerous
*What Digenean czs Blackspot Dz & uses molluscs as 1st intermediate host, fish as 2nd & pisciverous birds/mammals as final hosts.D. scudderi
*What Digenean is the “Eye Fluke”, found in many freshwater fish? Czs opacity of lens & blindness.F. diplostomidae
Which zoonotic Digenean is found in Cyprinids in Thailand, associated w/ cancer in humans.Opisthorchis viverrini
Name another zoonotic Digenean found in Asia that czs laryngo-tracheitis in man.Clinostomum complanatum
Which cestode can cz comression/distortion of viscera & inhibit gonadal maturation bc of pressure necrosis. How can you control this pest?F. ligulidae. Control by removal of piscivorous bird final host
Which parasite in fish is also the broad tapeworm of man (zoonotic)F. diphyllobothrium
*Which 2 nematoads are zoonotic?Cod worm & Herring worm
*What crustacean is extremely dmging to fish. Wounds inflicted by hooks/suckers are found on the skin & fins. Can infect most freshwater fish.Argulus (aka Fish Louse)
*What copepod is a very dangerous parasite, esp. to young fish? Even a few parasites can cz death.Lernae (aka Anchor Worm)
*Which freshwater parasitic copopod can be found attached to gills, branchial cavity, skin & fins of Salmonids?Lepeophterios salmonis (aka Salmon Louse)

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