Fish (MC) Flashcards by Linde Saunders

Damage to the dermis/epidermis leads to damage of what underlying structure?

scales

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**Response to insult - impact upon what 4 things

Ammonia excretion Gas exchange Acid-Base balance Salt Regulation

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***Where would you want to look for pathogens that are systemic or affect the tail? Why?

Look at the kidney
- Sinusoids of anterior kidney and peritubular capillaries are lined by renal portal MOs
  - which pick up most of the pathogens in the body and from the tail

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Which heart layer contains coronary blood vessels? What types of fish is it best developed for?

Compact layer Fast-swimming, active fish

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Spongy heart does not contain coronary blood vessels so it uses venous blood instead of oxygenated blood. Which metabolic pathway does it use?

Glycolytic

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In fish, Cardiac Output is more of a fnx of ___________

more a fnx of stroke volume than heart rate

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***Does ammonia by itself damage gills?

NO fish can adjust to increase ammonia levels; can lead to coma

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***Why is it best to have a hospital tank set up to tx fish instead of treating the tank they are in most of the time?

B/c when you treat the tank –> treat filtration system –> fish may survive dz but then die from water quality problems

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***What are the levels of free vs. ionized ammonia dependent upon

Dependent upon temp & pH

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How can you remove chlorine from water

Aeration Zeolites (clays) Activated charcoals

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What are melanomacrophages? Where are they found?

“cellular trashcans” –> lock away AG, dead cells Found in places w/high cellular turnover (spleen, kidney, liver, ovary hematopoietic tissue)

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What is the function of retinal pigmented epithelium

Controls the amt of light (photoreceptors encased in melanin –> protects during day)

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How can you tell if a fish dies in the day? night?

Day - photoreceptors will be tall Night - photoreceptors will be short

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Fish tissues that regenerate

Muscle & Cardiac Myocytes CNS Retina

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When does supersaturation of water occur?

Rapid increase in water temp or decrease pressure

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What causes gas bubble dz? Tx?

Water is supersaturated w/gas Oxygen or Nitrogen –> bubbles of gas in blood cause emboli in vessels of gills, pseudo branch, &choroid gland Tx: Vigorous aeration or agitation

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Nitrite causes _______

suffocation by irreversibly binding Oxygen (via methhemaglobin)

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What agent is responsible for characteristic “hole in head”/white spot dz

Edwardsiella ictaluri

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What agent is responsible for gas filled dermal & muscular lesions; emphysematous = putrid

Edwardsiella tarda

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Atypical bacterial gill dz is a condition commonly affecting _____.

C/S? Lesions?

salmonids in low water temperatures
C/S: Lethargy/”Sleepy”, decreased fright response, will still eat
Lesions: atrophied/”stumpy” lamellae covered in Pseudomonas

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Why is nitrite not as big of a concern in salt water fish?

Cl- competes w/nitrite in gills

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What causes respiratory distress syndrome

In warm or polluted waters, where O2 levels are low, the cost of extraction by the gills may be too high (the energy required for ventilation exceeds that released by the O2 so obtained)

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What happens if there is a build up of CO2

Acidiosis–> increased gas levels (swim bladder & choroid) Exophthalmia Distended swim bladder Won’t submerge properly

What agent is responsible for Hemorrhagic Septicemia Dz

Aeromonas hydrophila

What agent is responsible for Furunculosis

Aeromonas salmonicidia

Pathognomonic for Furunculosis

Cardiomyopathy (will see bact. in spleen, kidney, and heart)

Function of gills

Respiration Osmoregulation Acid-Base balance Excretion of Nitrogenous Waste Salt Regulation

\*\*\*Where is a good place to look for inflammation in gills?

Central venous sinus of filaments (can see neutrophils pouring out)

What is unique about the endocardial cells lining the trabecular

They increase surface area, highly phagocytic & have CYP-450

Most common cause of cataracts

zinc deficiency

#2 most important dz affecting Koi

Costia (Icthyobodo neator)

Parasites restricted to GI --\> PLE --\> protein casts

Hexamitids salmonis

What does histozoic & coelozoic mean? Which is more damaging?

Histozoic --\> w/in tissue --\> more damaging Coelozoic --\> w/in cavities & lumens

\*\*\*What feature allows Gyrodactylids to multiply fast?

Some are viviparous --\> they give live birth --\> can multiply fast

\*\*\*Which is more problematic: adult cestodes or larval cestodes?

larval cestodes

What causes coffee ground nucleus w/dark cytoplasm w/in skin/gill epithelium and affected fish seem agitated and exhibit flashing? What is the major issue with this?

Ichthyophthirius multifillis/Ich/White spot Breaks osmoregulation of tissue

\*\*\*Fish tumors do NOT metastasize EXCEPT \_\_\_\_\_\_\_\_

Aflatoxin induced hepatic carcinoma

Reportable dz that invades the cartilage of head & spine --\> labyrinth involvement --\> whirling & spinal deformities

Myxobolus cerebralis (Whirling Dz)

What measures can be taken to prevent Whirling Dz?

parasites are mud dwelling --\> keep young fish in concrete pond until \>6m & cartilage ossifies to bone

What can occur if O. pseudophyllidea cestodes get too large?

pressure necrosis of visceral organs & parasitic castration

Causes gastric granulomas in people

Anisakis and Pseudoterronova

Viruses reportable to OIE

IHN (Infectious Hematopoietic Necrosis) VHS (Viral Hemorrhagic Septicemia) ISA (Infectious Salmon Anemia) EHN (Epizootic Hematopoietic Necrosis) SVC (Spring Viremia of Carp) Oncorrhynchus Masou Virus (Herp 2) Koi Herpes

Infectious Pancreatic Necrosis (IPN) path.

Necrosis of pancreatic acinar cells & mesenteric fat

IPN C/S

Anorexia, darkening, distended abdomen , exophthalmia NO myocarditis

Infectious Hematopoietic Necrosis (IHN) causes

acute necrosis of all cell types in the kidney and spleen Classic lesion - Melanomacrophages are totally necrotic in kidney

Causes viral encephalopathy vacular degeneration in brain and retina

Nodavirus (like BSE)

Causes hemorrhage in muscle as well as other places like choroid gland and heart --\> exophthalmia and vascular damage

Viral Hemorrhagic Septicemia (VHS)

Carp Pox agent? Koi Herp agent?

Carp pox - Herp 1 Koi herp - Herp 3

1 of 2 top dz in Koi; high mortality

Koi Herp

Very common, doesn't kill; iridovirus is the agent

Lymphocytosis

Lymphocytosis pathogenesis --\> C/S

fibroblast replicate in dermis --\> cytomegaly - grapelike clusters of cysts on skin

Alphavirus cause what dz in salt water fish? What is the "equivalent" in fresh water fish?

Pancrease Dz Sleeping Dz - freshwater

Alphavirus in pancreas dz causes

loss exocrine pancreas rhabdomyopathy - heart and skeletal muscle

Low Vit E associated with alpha virus leads to

oxidative stress

The difference b/w pancreas dz and sleeping dz beside salt vs fresh water is that sleeping dz has really severe \_\_\_\_

red muscle necrosis (heart and skeletal)

Infectious Salmon Anemia causes

hepatonecrosis, interstitial hemorrhage, & acute coagulative kidney tubular necrosis