Zebrafish Flashcards by Cassandra Cullin

Etiology?

Gas bubble disease

Caused by gas supersaturation of water

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Etiology? Location in body?

Pseudocapillaria tomentosa

Found in lumen and wall of intestine

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GIT from a zebrafish. Etiology? Treatment?

Pseudocapillaria tomentosa

Treat with emamectin-medicated diet or fenbendazole in Artemia suspension

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Etiology? Treatment?

Ichthyophirius multifilis (Ich)

Treat with removal of affected fish + increasing temperature to accelerate lifespan of motile form; formaldehyde immersion, salt treatment

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Etiology and 2 sequela of infection

Piscinoodinium sp. (velvet disease)

Sequela

(1) damage to host cell leading to osmoregulatory impairment and secondary bacterial infection
(2) Inflammation and hyperplasia of gill epithelium lead to hypoxia

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Etiology and 2 predisposing factors.

Saprolegnia in fry.

Predisposing factors–>skin wounds, handling, crowding, heavy feeding rates, immunosuppressionn, high organic loads in tanks

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Most likely etiology and how it is transmitted.

Pseudoloma neurophilia

transmitted by ingestion, gets into tank via infected live/dead fish, splashing/aerosolization between tanks, debris, vertical transmission via ovaries, ova, and embryos spawned from infected adults

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Most likely etiology and expected clinical signs

Pseudoloma neurophilia

Expect emaciation (aka ‘skinny dz’), lordosis, scoliosis, reduced growth, reduced female fecundity

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Etiology and species most affected by this disease

Columnaris caused by Flavobacterium

Affects salmonids

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Etiology and other species that may be affected.

Edwardsiella ictaluri

Causes ‘hole in the head’ in catfish

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Primary differential for the zebrafish shown and predisposed strains.

Mycobacterium.

Tubingen (TU) and TAB5 more susceptible

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Common name for this clinical sign?

Dropsy (edema)

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Reason for this behavior in zebrafish

Hypoxemia

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Disease model shown in the fish on the right and the mutation associated with this phenotype

melanoma casued by BRAF gene

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Mutation shown? Ortholog in mice?

No tail (ntl)

In mice, see brachyury (T)

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Scientific name of the zebrafish

Danio rerio

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What is it called when adult male fish are treated with chemical mutagen and the F3 generation is examined for developmental abnormalities?

Saturation mutagenesis

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What family are zebrafish in?

Cyprinidae (includes danios and barbs)

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What is the ntl mutation

no tail–>embryos fail to develop a proper notochord and caudal structures

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what is the spt mutation?

spadetail, mesodermal cells fail to gastrulate properly

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What is the standard temp for zebrafish maintenance?

28.5C

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When does the first cleavage occur for zebrafish embryos?

45min after fertilization

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What is epiboly?

when embryonic cells spread over the yolk

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When do embryos hatch from the chorion?

3-4dpf

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When do zebrafish start eating?

4-5dpf

What type of tumors does ENU usually produce?

epidermal papillomas

What does the c-myc gene induce in zebrafish?

T-cell acute lymphoblastic leukemia

What muscular dystrophy is seen in zebrafish?

Duchenne muscular dystrophy

If the distal part o the zebrafish fin is amputated, how long will it take to regenerate?

10-12d

Disease and infection are a result of interaction between what 3 aspects?

host, environment, pathogen

Poor health in zebrafish is a general indicator of what?

marginal to poor environmental values

T/F: zebrafish aren't territorial.

F- they are

What housing density is recommended by the Guide for zebrafish?

No more than 5 fish/L

Tight/cohesive shoaling, frequent or constant aggression, erratic bursts of activity, freezing and bottom-dwelling are examples of what type of behaviors?

Abnormal/maladaptive behaviors

What is the acclimated thermal tolerance range of zebrafish?

6.7-41.7C

When changing the temperature of a zebrafish tank, what is the highest amount it should change per day?

1.5C

What is the optimal growing/breeding temperature for zebrafish

75-82F (24-28C)

How warm should an aquatic room be kept to minimize condensation of water on surfaces?

1-2 degrees above that of the water

What are signs of oxygen deprivation in tanks?

fish clustered around aerators, gasping/sipping at the top of the water

Supersaturation of water with oxygen leads to what disease?

gas bubble disease -air emboli in tissues

What is the optimum pH for zebrafish systems?

8-Jul

What is the effect on ammonia in a tank when the pH is increased?

higher unionized toxic ammonia

What is the effect on ammonia in a tank when the pH is decreased?

inhibits activity of nitrifying bacteria which will increase the overall ammonia level

What does conductivity measure in relation to fish tanks?

indicator of the total amount of dissolved ions in a solution, direct measure of the amount of electric current a particular soulution can conduct

What salinity should zebrafish be kept at?

125-2500 microseimens (uS)

What elements are measured in water hardness?

calcium, magnesium salts

What is the ideal water hardness for zebrafish?

80-200ppm

What can be used to replace the minerals in RO water used for fish tanks?

calcium carbonate, crushed coral, aragonite

What should be a consideration in the composition of housing rooms for aquatic species?

exposure to high humidity and/or water

When sealing aquatic tanks, what compound should be used?

food-grade silicon sealer

How much light is recommended for zebrafish?

5-30 ft candles or 54-354 lux

What type of outlet should be used in aquatic rooms?

ground fault interrupted (GFI) with covers

How much does 1 gallon of water weigh?

8.3lb/3.75kg

T/F: Wood is safe to use long-term to support aquatic systems when it is treated.

F- even if treated, don't use it!

What is the best source of water for fish?

deep wells- few infectious agents or toxic chemicals

How should municipal tap water be treated prior to use in aquatic systems?

Remove chlorine, chloramines, copper

What material is best to make zebrafish tanks from?

Polycarbonate

how much of the total water volume should be replaced in recirculating water systems?

1-10% of water volume

What biological algae control can be used in zebrafish but can be vectors of certain pathogens?

snails (Planorbella spp)

What fatty acid should be provided to zebrafish in high amounts?

linoleic acid

What diet promotes high growth rates and survival for zebrafish larvae and fry?

zooplankton (rotifers, Artemia)

What is the best way to introduce imported fish lines into a colony?

To only allow the progeny to enter the colony

What is a quarantine model called that only allows progeny from previously imported surface disinfected embryos that were reared to adults in the quarantine facility to enter the colony?

refined quarantine

What is a quarantine model called that allows surface disinfected embryos from adult fish housed in the quarantine facility the facility

traditional quarantine

How should embryos be disinfected?

dilute bleach 20-50ppm buffered to pH 7.0

How long should sentinel fish be maintained in a system to detect chronic infections?

3 months

What is the primary hematopoietic organ in adult zebrafish?

Head kidney

What are 2 methods of terminal blood collection?

decapitation through the pelvic girdle, draw from the dorsal aorta

What are survival blood collection techniques in fish?

dorsal aorta draw

What is special about zebrafish RBCs?

They are oval and nucleated

How much solution an be gavaged safely to a zebrafish?

5uL

What are the four stages of sedation?

I-sedation, II- excitation, III- anesthesia, IV-overdose

What is commonly used to induce anesthesia in zebrafish?

MS-222 (tricaine methanosulfonate)

What must be added to eugenol to make it water soluble?

ethanol

What are the two pathogenic species of mycobacterium in fish?

M. haemophilum, M. marinum

What is the most commonly identified mycobacterium in zebrafish?

M. chelonae

Where do aquatic mycobacterium reproduce in fish?

host macrophages

What strains of zebrafish are more susceptible to mycobacterium?

Tubingen (TU), TAB5

Lethargy, decreased fecundity, emaciation, skin ulceration, edema, and coelemic distension are associated with what disease?

Mycobacterium

How is mycobacterium in fish diagnosed?

Acid-fast stain of lesions, PCR, culture

What is the only species of mycobacterium that has a neurotropic form in fish?

M. haemophilum

How is mycobacterium treated in fish?

It's not- rederive the system

What is the causative agent of fish tank granuloma in people?

Mycobacterium marinum

What is the causative agent of hole in the head disease in catfish?

Edwardsiella ictaluri

How are zebrafish infected with Edwardsiella?

immersion in infective water

What two syndromes are present in catfish affected by Edwardsiella ictaluri?

septicemia, hole in the head

What are the clinical signs associated with Edwardsiella in zebrafish?

lethargy, raised scales, skin ulceration and hemorrhage, ascites

What are the two organs most severely affected by Edwardsiella in zebrafish?

kidney, spleenn

What protozoan parasite is associated with Aeromonas hydrophila in zebrafish?

Tetrahymena pyriformis

How is Aeromonas diagnosed?

culture isolation of kidney

What is the causative agent of bacterial gill disease?

Flavobacterium branchiophilum

What is the causative agent of columnaris disease?

Flavobacterium columnare

What is the characteristic lesion of columnaris disease?

saddleback lesion- loss of pigment and scales around dorsal fin

How is columnaris disease diagnosed?

wet mount microscopy

T/F: columnaris is a low mortality disease

False- high mortality, especially in salmonids and zebrafish

What two microsporidian parasites most commonly infect zebrafish?

Pseudoloma neurophilia, Pleistophora hyphessobryconis

What is the most common zebrafish disease?

Microsporidiosis due to Pseudoloma neurophilia

Where does Pleistophora hyphessobryconis develop in the zebrafish?

Skeletal muscle

Where does P. neurophilia develop in the host?

CNS tissues, muscle, ovary

What are clinical signs associated with P. neurophilia in zebrafish?

emaciation, lordosis, scoliosis, reduced growth

How is P. neurophilia diagnosed?

direct visualization of spores on wet mount, histologic visualization with acid-fast, H&E, Gram, Luna, PAS, or Fungi-Fluor stains

What is the causative agent of velvet disease or gold dust disease?

Piscinoodinium sp.

What age category of zebrafish has the highest mortality due to Piscinoodinium?

young fish

How is Piscinoodinium diagnosed?

Wet mount of skin or gills with oval opaque nonmotile trophonts

How is Ich diagnosed?

pathognomonic horseshoe shaped macronucleus seen on wet mount

What is the lethal amount of ammonia for fish

0.5mg/L

Some zebrafish present with pale tan and brown gills, lethargy, tachypnea and surface swimming. What is the most likely diagnosis?

nitrite toxicity

What is the lowest toxic concentration of nitrite for zebrafish?

0.1mg/L

How should chloramine be removed from an aquarium before fish are added?

activated carbon filter, chemical neutralization with sodium thiosulfate, near-boiling of water

How is chlorine/chloramine toxicity treated?

New water source and supersaturating with O2 for several days

How is chlorine removed from a water source?

24h aeration or dechlorinating agent

High CO2 levels (\>12mg/L) are associated with what condition in zebrafish?

nephrocalcinosis

What is the most common spntaneous tumor in male zebrafish?

seminoma

How is egg-associated inflammation prevented in females?

prevent egg retention by spawning females in a timely manner