Zebrafish Flashcards
Etiology?
Gas bubble disease
Caused by gas supersaturation of water
Etiology? Location in body?
Pseudocapillaria tomentosa
Found in lumen and wall of intestine
GIT from a zebrafish. Etiology? Treatment?
Pseudocapillaria tomentosa
Treat with emamectin-medicated diet or fenbendazole in Artemia suspension
Etiology? Treatment?
Ichthyophirius multifilis (Ich)
Treat with removal of affected fish + increasing temperature to accelerate lifespan of motile form; formaldehyde immersion, salt treatment
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
Etiology and 2 predisposing factors.
Saprolegnia in fry.
Predisposing factors–>skin wounds, handling, crowding, heavy feeding rates, immunosuppressionn, high organic loads in tanks
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
Most likely etiology and expected clinical signs
Pseudoloma neurophilia
Expect emaciation (aka ‘skinny dz’), lordosis, scoliosis, reduced growth, reduced female fecundity
Etiology and species most affected by this disease
Columnaris caused by Flavobacterium
Affects salmonids
Etiology and other species that may be affected.
Edwardsiella ictaluri
Causes ‘hole in the head’ in catfish
Primary differential for the zebrafish shown and predisposed strains.
Mycobacterium.
Tubingen (TU) and TAB5 more susceptible
Common name for this clinical sign?
Dropsy (edema)
Reason for this behavior in zebrafish
Hypoxemia
Disease model shown in the fish on the right and the mutation associated with this phenotype
melanoma casued by BRAF gene
Mutation shown? Ortholog in mice?
No tail (ntl)
In mice, see brachyury (T)
Scientific name of the zebrafish
Danio rerio
What is it called when adult male fish are treated with chemical mutagen and the F3 generation is examined for developmental abnormalities?
Saturation mutagenesis
What family are zebrafish in?
Cyprinidae (includes danios and barbs)
What is the ntl mutation
no tail–>embryos fail to develop a proper notochord and caudal structures
what is the spt mutation?
spadetail, mesodermal cells fail to gastrulate properly
What is the standard temp for zebrafish maintenance?
28.5C
When does the first cleavage occur for zebrafish embryos?
45min after fertilization
What is epiboly?
when embryonic cells spread over the yolk
When do embryos hatch from the chorion?
3-4dpf
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