Post on 16-Dec-2015
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
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.