Fish Disease Flashcards
Opportunistic infection Spp: Channel Catfish, Japanese eels, Occurs at high temp and organic pollution Uncommon zoonosis 3-5mm red cutaneous foci on flanks and peduncle (Catfish); supparative coelomic infection (Jap. eels).
Obligate pathogen Spp. Channel catfish Open ulcer on frontal bone (encephalitic form), peritoneal effusion (Acute septicemic form)
“red sore disease” aeromonas hydrophilum
Pathogenesis: Opportunistic pathogen, polluted water, high temps, overcrowding; found with water molds, and epistylis protozoan
Zoonotic (low risk) -exposure of wounds, ingestion of infected fish
CS: White or hemorrhagic masses on skin, mouth, or gills
Assoc. with GN infection
Dx: Isiolation from the kidneys.
Tx: formalin (), Pot. permanganate, Salt water, antibiotics
Leech “Myzodbella”
tx: Organophosphate
“Cyclops” Free living
“Ergasalid” FW and MAR- cephalothorax and abdomen “Lernaeidae”- Anchored female- Koi, goldfish Tx: Organophosphate prolonged immersion( x amount q 7d for 28 days) Or Diflubenzuron prolonged immersion
“Argulus” Focal red lesions, erratic behavior Cyprinids, centrarchids, salmonids 2 month life-cycle Tx: Organophosphate prolonged immersion; Formalin bath; Potassium permanganate May serve as intermediate host for fish nematodes
Isopods
“Flabellifera-Cymothoids”- 6cm “Gnathiidae”- larvae are infected, live in anemones Tx: Organophosphate, biologic control (cleaner fish),
Monogeneans
Monopisthocotlea (dactogyrids (ovip), gyrodactylids (Vivip), capsalids “benedenia- 2 pairs of anchors”, “Neopenedeia-3 pairs anchors” (Ovip))- centralized hooks -Oviparous- free swimming stage is infective Polypisthocotyleans-Sucking clamps CS: Mucus production, pruritis, anemia Tx: FW bath (for small species) - 1 hour Formalin (25ppm prolonged immersion EOD x 3tx) Organophosphate bath (resistance in some monogeneans)-2-5ppm trichlorfon for 60 minutes) Reduce crowding (for viviparous monos which transmit fish to fish) Potassium Permanganate (5ppm x 1 hour) Copper (Prolonged immersion) 0.15-0.2mg/L Chloramine T
“Ergasalid”
- similar to free- living but with antennae for grasping
- ~2mm long
- cephalothorax and abdomen
Species: FW >MAR
-Life-cylce- 1-5 free living nauplius stages, 105 free living copepod statges, 1 pre-adult, then adult
Lernaeids “Anchor worms”- Lernae
Dx- Scope, wet mount
Locaton- gill arches, oral cavity
Species: common in Koi, but can affect any fish
Life-cycle: lay larvae every 2weeks for 16 weeks, hundred of larvae
Female penetrates skin
Can cause hemorrhage or secondary bacterial infection at att. site
Tx: Manual removal, Potssium permanganate
*Organophosphates* “Diflubenzuron” q 7 d x for 4 weeks- not legal in farmed fish
*Sodium chlorite (20-40ppm) prolonged immersion with EOD water changes for 2 weeks.
Found on skin and gills
Viviparous- Feeds for 6 days on host, falls off, continues growing T
x: Formalin (Except lookdown turbs); Organophosphate
Monopisthocotlea
Oviparous “Live bearer”
Tx:
Monopisthocotlea
Viviparous
Infx skin and gill in MAR and FW species
Tx: FW bath (for small species) - 1 hour Formalin (25ppm prolonged immersion EOD x 3tx) Organophosphate bath (resistance in some monogeneans)-2-5ppm trichlorfon for 60 minutes) Reduce crowding (for viviparous monos which transmit fish to fish) Potassium Permanganate (5ppm x 1 hour) Copper (Prolonged immersion) 0.15-0.2mg/L Chloramine T
Monopisthocotlea
“benedenia- 2 pairs of anchors”
“Neopenedeia-3 pairs anchors”
Oviparous, centralized hooks, free swimming stage is infective CS: Mucus production, pruritis, anemia Tx: FW bath (for small species) - 1 hour Formalin (25ppm prolonged immersion EOD x 3tx) Organophosphate bath (resistance in some monogeneans)-2-5ppm trichlorfon for 60 minutes) Reduce crowding (for viviparous monos which transmit fish to fish) Potassium Permanganate (5ppm x 1 hour) Copper (Prolonged immersion) 0.15-0.2mg/L Chloramine T
Polypisthocotyleans-Sucking clamps
CS: Salt dusting
Tx: Formalin- 25ppm q EOD for 2 weeks with a water change on alternate days- variable success (most effective if administered late at night as this is when Tomites excyst)
Leteux-Meyer-25ppm formalin and 0.1ppm
Hyposaliity- < 16ppt for 14d, or <10ppt for 3h q 3d x 4 tx
MW or FW fish
Location: S/G, somtimes repro or GI
CS: Skin erosions, anorexia
Tx:
Water change- correction of water quality abnormalities
Formalin Bath or prolonged immersion
Potassium permanganate prolonged immersion
Acetic acid bath (FW only)
SW bath (FW only) vs. FW bath (SW only)
Copper prolonged immersion
Chilodonella piscicola and hexasticha
Cilliate (cilia on ventral surface)
30-80 x 20-60um
Location: SG
CS: tattered skin, blue sheen on body
Tx: Formalin bath or prolonged formalin immersion
“Marine velvet disease”
Marine analogue of cholodonellosis
causes acute mortalities in troical fish
Oval shape wiht numerous ciliary rows
56-86 x 32-50um
Tx: Formalin Bath 50ppm
Free living ciliate that can be lethal
causes mucus production and epithelial damage
30-60 x 50-100um
Tx: Formalin
Scuticociliatosis
Uronema marinum
MAR fish
Found on skin, gills
CS: ulceration/depigmentation of skin, Dyspnea
Tx: FW bath followed by a 24 hr formalin prolonged immersion
Amyloodinium “Marine velvet disease”
Dinoflagellate
Warm water, MAR fish
CS: Golden/dust sheen on scales, flashing
Tx: Tx free swimming dinospore (trophonts and tomonts are resistant)
Copper - 0.15mg/L (using 1mg/ml Copper stock solution)
FW dip- removes
Found on skin and gills
Very small (5-8 x 10-15um)
two forms: detached mobile form (2-4 flagella) or adhered pyriform
Tx: Formalin tx; saltwater (for FW fish only)
FW Ciliate
C- shaped maconucleus seen in trophonts
Catfish and loaches particularly susceptible
Tx: Formalin 25-50ppm x 3tx with water change on alternate days; Copper (pond fish), Formalin and Malachite green
Found on gills of FW or MAR fish
Found in polluted FW or MW
Attaches to gills via recurrent flagellum
Tx: Formalin bath or prolonged immersion
Gills
Found in salmonids
Tx: 2-6hr FW bath
Found on wet mount of F or G
Sessile/solitary = Apisoma, Ambiphyra, Riboscphidia
Caprinana- tentacles that emanate- can cause mechanical blockage of the gills
reproduce by binary fision
Tx: Formalin bath, prolonged immersion; Copper prolonged immersion
“Red sore disease”
“Epistylis”
Often assoc. with a mixed Gram negative bacteria known as “Red-sore disease”
Common in pond-raised fish
Reproduce by binary fision
Can be free-living , colonizing debilitated fish
Produces wite or hemorrhagic lesions on the flanks or tips of bony prominences such as the fins, jaws or gill operculum
May also become invaded by water molds
Spp. Centrarchids, ictalurids
Dx: wet mount of S/G
CS: amorphous masses on skin or mouth
Tx:
Formalin bath or prolonged immersion
K permanganate
Salt bath 3 x weekly
Salt prolonged immersion
“Saproleniosis, oomycete infection”
CS: Cottony proliferations
Class: oomycetes
Orders: Saprolegnia, Letomitale, peronosporales
Opportunistic, called “winterkill” during cold months
Tx: Prolonged salt immersion; Copper prolonged immersion; Malachite green (Leutex Meyer)
- Aphoanomyces invadans* “Epizootic Ulcerative Syndrome”
- Atypical water mold infection- containing broad Aseptate hyphae
CS: Causes deep penetrating ulcers
Issue in estuarine fish in the w atlantic and astralo-pacific and S. Asia
Dx: Culture with Glucose-yeast medium
Tx: NO known treatment. Can try malachite green or leteux meyer.
Effects skin and gills “saddleback” disease
FW fish
Dx: wet mounts (long, thin rods ~0.5-1.0 C 5-10um, gliding motions
CS: EPithelial disease–> erosive, necrotic skin and gill lesions (witish plaques with red periphery), or fins (especially caudal fin)
Gill infection less common but more serious
pathogenesis: Opportunistic; Found at increasing temperatures
Mineral content is important (less pathogenic in soft water)
Tx:
Potassium permanganate
Copper sulfate
3ppt salinity can preven tdisease
“Bacterial Cold water disease”
Dx: Wet mounts of skin , with long, thin rods
Opportunistic
CS: spring, temps < 50F; subacute to acute infection in young fish (distended abdomen, exophthalmia, severe anemia); scoliosis, lordosis in older fish
Associated with erythrocyte includion syndrom
Spp: FW salmonids (problem in hateries), esp. Coho salmon; cyprinids, and eels, Rainbow trout
Tx: Quaternary ammonium, chloramine-T or copper sulfate;often fish require systemic antibiotics
Virus of MW antd FW fish
CS: salt-like dusting on the body, may coallesce to masses
Spp: does not effect salmonids, catfish or cyprinidsTx/Pathogenisis: Chronic (usually many weeks)- self limiting, no tx.
Glochidia-producing FW bivalve molluscs
Pathogenesis- Infective larvae are released by adult clams and dispersed passively to gills and skin of fish using sharp hooks
Photobacterium Damselae ssp piscida
Causes chronic mortalities.
Small hemorrhages on operculum or base of skin.
Causes anemia, skin ulcers
Tx: TFM (3-trifluoromethyl-4-nitrophenol
