Fish Health ProtocolsFish Health Protocols

Chris MacWilliams, DVMChris MacWilliams, DVM

Principles of DisinfectionPrinciples of Disinfection

Disinfection: process that reduces or eliminates pathogenic Disinfection: process that reduces or eliminates pathogenic microorganismsmicroorganisms

Cleaning is the most important step in the Cleaning is the most important step in the cleaning and disinfection processcleaning and disinfection process

Cleaning process has 5 steps:Cleaning process has 5 steps:Dry cleanDry cleanWet washWet washRinseRinseDry Dry InspectInspect

Methods of DisinfectionMethods of Disinfection

PhysicalPhysical– Moist heatMoist heat– UV lightUV light– DryingDrying– Exposure to sunlightExposure to sunlight

ChemicalChemical– Chlorines (bleach)Chlorines (bleach)– Iodines (Ovadine)Iodines (Ovadine)– Quaternary ammonium compounds (Diquat, Roccal)Quaternary ammonium compounds (Diquat, Roccal)– Oxidizing agents (Virkon, Ozone)Oxidizing agents (Virkon, Ozone)

Chemical DisinfectantsChemical Disinfectants

Considerations:Considerations:– Proven efficacy against pathogens of interest:Proven efficacy against pathogens of interest:

Bacteria, virus, protozoans, fungus, sporesBacteria, virus, protozoans, fungus, spores

– SafetySafetyFish, user, equipment, environmentFish, user, equipment, environment

– AffordableAffordable– Other:Other:

Presence of organic matter Presence of organic matter

Effects on metals/fabrics/rubberEffects on metals/fabrics/rubber

Iodophors Hypochlorites Oxidizers Quaternary ammonium compounds

Brand Name Ovadine Chlorine Bleach (12%)

Virkon/Peroxigard (7%)

Roccal, benzalkonium chloride

Bactericidal +++ ++ +++/+++ +++

Virucidal ++ +++ +++/+++ _

Lipophilic virucidal

+++ +++ +++/+++ +

Sporicidal +++ +++ ++/++ _

Fungicidal +++ + ++/++ ++

Effectiveness inpresence of organicmatter

+ + +++/++ ++

Mechanism of action

Iodophors

Oxidizes proteins and interferes with metabolic reactions

Hypochlorites

Free hypochlorous acid attacks sulfur bonds and general structure in microbial enzymes, other proteins

Oxidizers

O2 release alters protein structure

Quat Ammonium

Cationic detergents. act against cell wall lipids in bacteria

Usage notes for working solutions (not accurate for concentrate)

Safe for skin contact, mild odor, color fades as potency declines, not effective if prepared with seawater

Corrosive to skin and metal, strong odor, high risk to fish, volatile, not effective if prepared with seawater

Safe for skin contact, mild odor/few volatiles, color fades as potency declines (Virkon), marked drop in efficacy if prepared with seawater

Safe for short or occasional skin contact, odorless, some risk to fish, not effective if prepared with seawater

Ovadine Egg Disinfection Ovadine Egg Disinfection

Why?Why?– Vertically transmitted diseasesVertically transmitted diseases

On the surface of the eggOn the surface of the egg

Within an eggWithin an egg

– Disinfecting eggs significantly decreases Disinfecting eggs significantly decreases pathogen loadspathogen loads

When?When?– During water hardeningDuring water hardening– After egg shocking and pickingAfter egg shocking and picking– After eyed eggs are transferred to a site After eyed eggs are transferred to a site

Ovadine Egg DisinfectionOvadine Egg Disinfection

How?How?

100 ppm = 10 mls of Ovadine per litre of water100 ppm = 10 mls of Ovadine per litre of water

– Determine volume of heath trayDetermine volume of heath tray– Add appropriate amount of Ovadine to tray full of waterAdd appropriate amount of Ovadine to tray full of water– Gently pour rinsed, fertilized eggs into tray preloaded Gently pour rinsed, fertilized eggs into tray preloaded

with Ovadine solution with Ovadine solution – After 10 minutesAfter 10 minutes without disturbance, restore water flow without disturbance, restore water flow

Ovadine Egg DisinfectionOvadine Egg Disinfection

1 volume of eggs : 10 volumes of 1 volume of eggs : 10 volumes of disinfectant solutiondisinfectant solution

Solution colour indicates efficacySolution colour indicates efficacy Brown = active Brown = active

Yellow = inactive and should be refreshedYellow = inactive and should be refreshed

Make a fresh Ovadine solution for each lot Make a fresh Ovadine solution for each lot of eggsof eggs

Ovadine Egg DisinfectionOvadine Egg Disinfection

Spent solution disposalSpent solution disposal– Dilution is standard, combined with hatchery effluent, Dilution is standard, combined with hatchery effluent,

or can be disposed to groundor can be disposed to ground

Neutralize:Neutralize:

Sodium thiosulfateSodium thiosulfate

0.78 X grams of iodine x 2 (safety factor)0.78 X grams of iodine x 2 (safety factor)

or 0.15 gm per litre of 100ppm solutionor 0.15 gm per litre of 100ppm solution

Water should be colourless before discharge to groundWater should be colourless before discharge to ground

Managing Egg Fungal InfectionsManaging Egg Fungal Infections

Egg pickingEgg picking– By handBy hand– Mechanical pickersMechanical pickers

Chemical treatmentsChemical treatments– Formalin (Parasite-SFormalin (Parasite-STMTM))– Hydrogen PeroxideHydrogen Peroxide– SaltSalt– Bronophol (EDR)Bronophol (EDR)– Malachite GreenMalachite Green

Egg PickingEgg Picking

Dead eggs are food for fungusDead eggs are food for fungus

After shocking eyed eggs – observe eggs After shocking eyed eggs – observe eggs for mortalitiesfor mortalities

remove dead eggs promptlyremove dead eggs promptly

Early – remove affectedEarly – remove affected

Grape cluster – remove clumpsGrape cluster – remove clumps

Beyond treatment – discard trayBeyond treatment – discard tray

Formalin Egg DisinfectionFormalin Egg Disinfection

1670 ppm for 15 – 20 minutes1670 ppm for 15 – 20 minutes

Static bath till last few weeks till hatchStatic bath till last few weeks till hatch– Then keep water flow >11 lpmThen keep water flow >11 lpm

Hanging IV bags or chicken feedersHanging IV bags or chicken feeders

Hydrogen peroxide (Perox-Aid)Hydrogen peroxide (Perox-Aid)

500ppm for 30 – 35 minutes daily500ppm for 30 – 35 minutes daily

Comparatively environmentally benign Comparatively environmentally benign

Will Will notnot work on established fungal work on established fungal infections – only preventativeinfections – only preventative

OthersOthers

Salt – Robertson Creek every 2 – 3 daysSalt – Robertson Creek every 2 – 3 days

Bronophol – no benefits vs approvedBronophol – no benefits vs approved

Malachite Green – absolutely not!Malachite Green – absolutely not!

Sample Shipping to a Diagnostic Sample Shipping to a Diagnostic FacilityFacility

Mortalities are unexpectedMortalities are unexpected

Clinical signs are suggestive of a disease Clinical signs are suggestive of a disease of concern (eg. popeye and/or swollen of concern (eg. popeye and/or swollen abdomens at a facility with a history of abdomens at a facility with a history of recurrent BKD infection)recurrent BKD infection)

Daily mortality rate exceeds 0.5% of the Daily mortality rate exceeds 0.5% of the populationpopulation

Selecting the samplesSelecting the samples

Moribund fish preferredMoribund fish preferred

There may be a need to randomly There may be a need to randomly sample apparently healthy fish from the sample apparently healthy fish from the populationpopulation

Ask Fish Path Lab staff re: sample type, Ask Fish Path Lab staff re: sample type, numbers and shipping infonumbers and shipping info

Before shippingBefore shipping

Collect fish history:Collect fish history:– population sizepopulation size– clinical signsclinical signs– mortality and morbidity ratemortality and morbidity rate– diet and feed consumptiondiet and feed consumption– water quality conditionswater quality conditions– records of recent stressful events (e.g. low water event, records of recent stressful events (e.g. low water event,

marking)marking)– vaccination statusvaccination status– disease and treatment historydisease and treatment history

Fill out a submission formFill out a submission form

Shipping Live FishShipping Live Fish

Line a cooler with ice paks or double bagged iceLine a cooler with ice paks or double bagged iceCover ice with newspaperCover ice with newspaperLive fish are added to heavy duty plastic bag filled ¼ to Live fish are added to heavy duty plastic bag filled ¼ to 1/3 full of aerated ambient water1/3 full of aerated ambient waterOxygen is pumped into the bag to refill it. Oxygen is pumped into the bag to refill it. The bag is securely closed off using elastic bands or The bag is securely closed off using elastic bands or tape. Double bag and placed in the Styrofoam cooler. tape. Double bag and placed in the Styrofoam cooler. Each bag is clearly marked with information identifying Each bag is clearly marked with information identifying contents. contents. The remaining space in the cooler is filled with cubed The remaining space in the cooler is filled with cubed ice to keep the fish and water cool.ice to keep the fish and water cool.The lid is placed on the Styrofoam cooler and securely The lid is placed on the Styrofoam cooler and securely fastened with duct tape to prevent accidental spillage. fastened with duct tape to prevent accidental spillage.

ShippingShipping

Include a Include a pathology laboratory submission formpathology laboratory submission form or an accompanying letter with more detailor an accompanying letter with more detail

Include copy of mortality records if availableInclude copy of mortality records if available

Clearly mark sample bagsClearly mark sample bags

The container is addressed to the laboratory at The container is addressed to the laboratory at PBS and is clearly labeled with information as to PBS and is clearly labeled with information as to originating site.originating site.

Contact lab with estimated time of sample arrival Contact lab with estimated time of sample arrival

Shipping fresh dead fishShipping fresh dead fish

Fresh morts (red gills, firm flesh) should Fresh morts (red gills, firm flesh) should be placed in labeled, sealed double be placed in labeled, sealed double plastic bags without water. plastic bags without water.

Ship dead fish in a container on ice as Ship dead fish in a container on ice as described above for live fish. described above for live fish.

Fish should not come in contact with the Fish should not come in contact with the ice or freezer packs.ice or freezer packs.