biosecurity and fish health management for recirculating systems

Biosecurity and Fish Biosecurity and Fish Health Management for Health Management for Recirculating SystemsRecirculating Systems

Julie Bebak-Williams, VMD, PhDJulie Bebak-Williams, VMD, PhD

Freshwater Institute Freshwater Institute

Shepherdstown, WVShepherdstown, WV

Why are infectious disease outbreaks Why are infectious disease outbreaks more likely to occur in the RAS?more likely to occur in the RAS?

Fish loading densities greater than those Fish loading densities greater than those used in pond or serial reuse systemsused in pond or serial reuse systems

Continuous production strategiesContinuous production strategies Prolonged water retention in system Prolonged water retention in system

provides extended residence time that provides extended residence time that allows for growth of opportunistic and allows for growth of opportunistic and overtly virulent pathogensovertly virulent pathogens

Relatively more stressful environment Relatively more stressful environment

Why does it matter (costs)?Why does it matter (costs)? CostsCosts

Diagnosis, response, diversion of management Diagnosis, response, diversion of management and labor, underutilization of production facilityand labor, underutilization of production facility

Direct losses from mortalityDirect losses from mortality Reduced quality of survivorsReduced quality of survivors Inability to replace stockInability to replace stock Restricted market for healthy stock because of Restricted market for healthy stock because of

damage to reputation and missed marketsdamage to reputation and missed markets Restriction of movement ordersRestriction of movement orders Facility closure ordersFacility closure orders

What is biosecurity?What is biosecurity?

Hazard reduction through Hazard reduction through environmental manipulationenvironmental manipulation

(Plumb, 1992)

Biosecurity

(Operating costs are reduced by minimizing the number and severity of disease outbreaks.)

Effective BiosecurityEffective Biosecurity

Reduces risk of pathogen introductionReduces risk of pathogen introduction Reduces risk that pathogens will spread throughout Reduces risk that pathogens will spread throughout

the facilitythe facility Reduces conditions that increase susceptibility to Reduces conditions that increase susceptibility to

infection and disease (e.g., reduce stress)infection and disease (e.g., reduce stress)

What is one strategy What is one strategy for “making up” for for “making up” for

losses?losses?

100,000 at Start100,000 at Start

<0.11 <0.11 lbs/gallbs/gal

0.11-0.210.11-0.21

lbs/gallbs/gal0.22-0.340.22-0.34

lbs/gallbs/gal

1 Inf1 Inf 76,06276,062 31,59531,595 25,79025,790

2 Inf2 Inf 37,38937,389 27,44927,449 24,48824,488

3 Inf3 Inf 26,70326,703 30,20130,201 22,46622,466

Starting Fish Density

Path

og

en

D

ose

Effect of Pathogen DoseEffect of Pathogen Dose

0

2

4

6

8

10

12

14

16

0 5 10 15 20 25 30 35 40 45 50 55 60

Time (days)

Dea

th r

ate

(%/d

ay) 1 Inf

2 Inf

3 Inf

All Inf

0 Inf

Rule of ThumbRule of Thumb

Every producer that transports fish Every producer that transports fish directly from a pond into a recirculating directly from a pond into a recirculating

system will experience catastrophic system will experience catastrophic losses from infectious disease outbreakslosses from infectious disease outbreaks

Opportunistic vs. Obligate Opportunistic vs. Obligate PathogensPathogens

Obligate pathogensObligate pathogens Require animal host to replicate Require animal host to replicate Viruses (IPNV, IHNV, VHSV and OMV in salmonids); bacteria Viruses (IPNV, IHNV, VHSV and OMV in salmonids); bacteria

(bacterial kidney disease, furunculosis?, enteric redmouth (bacterial kidney disease, furunculosis?, enteric redmouth disease)disease)

Opportunistic pathogensOpportunistic pathogens Do not require animal host to replicate – nutrition from organic Do not require animal host to replicate – nutrition from organic

materialmaterial Naturally occur in soil and waterNaturally occur in soil and water May also be part of the natural microbial population in the fish May also be part of the natural microbial population in the fish

(e.g., the gastro-intestinal tract)(e.g., the gastro-intestinal tract) Includes the species associated with bacterial gill disease, Includes the species associated with bacterial gill disease,

coldwater disease, columnaris disease, and the motile coldwater disease, columnaris disease, and the motile aeromonads. Opportunistic parasites include aeromonads. Opportunistic parasites include TrichodinaTrichodina, , ChilodonellaChilodonella, , Ichthyobodo?Ichthyobodo?, , EpistylisEpistylis and and AmbiphyraAmbiphyra. The fungi . The fungi can also be considered opportunistic pathogens. can also be considered opportunistic pathogens.

Biosecurity planning starts at the Biosecurity planning starts at the facility design stagefacility design stage

Includes consideration ofIncludes consideration of Placement of doorsPlacement of doors Placement of disinfection areasPlacement of disinfection areas

Ventilation – to control insects, dust and Ventilation – to control insects, dust and aerosol transfer (also can use barriers)aerosol transfer (also can use barriers)

Facility designFacility design

Reduce noise and vibrationReduce noise and vibration Arrange tanks so that they are easily accessibleArrange tanks so that they are easily accessible Ability to take individual tanks and unit processes Ability to take individual tanks and unit processes

off line for cleaning or chemical treatmentoff line for cleaning or chemical treatment Construction materials – non-porous and easy to Construction materials – non-porous and easy to

clean and disinfect (plastic, metal, PVC)clean and disinfect (plastic, metal, PVC) Avoid use of wood (consider disposable)Avoid use of wood (consider disposable) Never transfer equipment to or from another siteNever transfer equipment to or from another site

Circular Tanks & Solids Circular Tanks & Solids RemovalRemoval

Advantages:Advantages: self cleaningself cleaning rapid solids rapid solids

fractionationfractionation uniform environmentuniform environment optimum rotational optimum rotational

velocityvelocity for swimming fishfor swimming fish

flow distributes feed flow distributes feed & fish& fish

Circular Tanks w/o Circular Tanks w/o RotationRotation

Solids must be “mucked-out” of Solids must be “mucked-out” of tank.tank.

Design features should be easy Design features should be easy and convenient to useand convenient to use

White River NFH

Clean Outs and Cone-bottom Unit Clean Outs and Cone-bottom Unit ProcessesProcesses

Solids should not build up Solids should not build up in any part of systemin any part of system:: Easy to cleanEasy to clean Unit processes (COUnit processes (CO22

stripper, LHO, biofilter) stripper, LHO, biofilter) designed to be cleaned designed to be cleaned (e.g., cone-bottom, ability (e.g., cone-bottom, ability to drain)to drain)

Include features to ease Include features to ease solids removal from system solids removal from system (e.g., clean outs)(e.g., clean outs)

Clean-Outs for Ozone ContactingClean-Outs for Ozone Contacting

sedimenttrap

sedimenttrap

Floor drainto culture tanks

ozon

ated

inle

t

StrippingColumn

13-40 min O3

Destruct

6-20 min O3

Contact

Foam & O3

Off-GasSeparator

Fan

Lamar NFH (PA)

Clean-Out Locations in all Clean-Out Locations in all SumpsSumps

COCO22 & O & O22 Control Control(Summerfelt et al., 2000)(Summerfelt et al., 2000)

LHO

cascade aeration column

Isolation of system componentsIsolation of system components

Tanks and unit processes that can be Tanks and unit processes that can be taken off linetaken off line & drained out of system & drained out of system For cleaning while the rest of the system is For cleaning while the rest of the system is

operating, then discharge out of the systemoperating, then discharge out of the system For chemical treatment of individual tanks, For chemical treatment of individual tanks,

discharge to a chemical draindischarge to a chemical drain

Bypass PipingBypass Piping Drain piping should Drain piping should

be plumbed to allow be plumbed to allow drum filter bypass to drum filter bypass to direct flow to:direct flow to: Drain (away from Drain (away from

RAS)RAS) during cleaning during cleaning

eventsevents Pump sumpPump sump

When servicing drum When servicing drum filterfilter

drain

drum filterpump sump

Bypass PipingBypass Piping Clean-outs with valves were installed Clean-outs with valves were installed

at the end of every pipe run.at the end of every pipe run. Discharge tank & pipe cleaning flows Discharge tank & pipe cleaning flows

into floor trench.into floor trench.

MCRA Hatchery, Delbarton, WV

Sump DesignSump Design

Sump design with no standing waterSump design with no standing water

White River Nat’l Fish Hatchery

Fish health monitoring allows Fish health monitoring allows early detection of a problemearly detection of a problem

Tank windowsTank windows Two locationsTwo locations

where healthiest fish where healthiest fish would bewould be

where sick fish would where sick fish would congregatecongregate

Mort RemovalMort Removal

Design features to remove dead fishDesign features to remove dead fish ““Mort Flush”Mort Flush”

Quantify mortalityQuantify mortality Reduce pathogen load on systemReduce pathogen load on system Remove weak/moribund fish for examinationRemove weak/moribund fish for examination

Unit processes in separate Unit processes in separate buildingbuilding

White River NFH

Avoid use of wood, unless Avoid use of wood, unless disposabledisposable

Equipment used for Equipment used for sequential cohortssequential cohorts

PVC sheets instead of PVC sheets instead of wood sheetswood sheets

MetalMetal

PlasticPlasticInexpensive & Easy to DisinfectInexpensive & Easy to Disinfect

I. Practices to Reduce the Risk I. Practices to Reduce the Risk of Pathogen Introductionof Pathogen Introduction

Water SupplyWater Supply

Specific-pathogen free (SPF) groundwater supplySpecific-pathogen free (SPF) groundwater supply For both well and spring waterFor both well and spring water

Investigate possibility of surface water input (depends on Investigate possibility of surface water input (depends on surrounding geology and depthsurrounding geology and depth

Test both before purchase of the propertyTest both before purchase of the property

Should be constructed to protect from surface Should be constructed to protect from surface water input and entry of animals (e.g., water input and entry of animals (e.g., invertebrates, amphibians, reptiles, mammals, invertebrates, amphibians, reptiles, mammals, birds) that could be carriers of pathogensbirds) that could be carriers of pathogens

If surface water must be used, then it must be If surface water must be used, then it must be disinfected disinfected

Eggs and FishEggs and Fish

Specific-pathogen-free certified eggs/fishSpecific-pathogen-free certified eggs/fish Eggs disinfected upon arrivalEggs disinfected upon arrival Quarantine new fish, certified or notQuarantine new fish, certified or not Avoid introduction of delivery waterAvoid introduction of delivery water

FeedFeed

Live foodLive food Presents a serious risk of contamination with Presents a serious risk of contamination with

pathogens -should be cultured as specific-pathogen-pathogens -should be cultured as specific-pathogen-free, never used directly from the natural environmentfree, never used directly from the natural environment

Commercial dry feedsCommercial dry feeds Steam-pelleted – 160-180 F (71-82 C)Steam-pelleted – 160-180 F (71-82 C) Expanded – 180-200 F (82-93 C)Expanded – 180-200 F (82-93 C) Extruded – 220-350 F (104-177 C)Extruded – 220-350 F (104-177 C)

Lyophilized feedLyophilized feed Many microorganisms survive lyophilization wellMany microorganisms survive lyophilization well

People ManagementPeople Management

Frequent washing of hands and arms with Frequent washing of hands and arms with antibacterial soap should be standard antibacterial soap should be standard practicepractice

Strategically schedule culture activities Strategically schedule culture activities (work on most vulnerable stages first, (work on most vulnerable stages first, minimize number of personnel working minimize number of personnel working on a group of fish, leave sick for last)on a group of fish, leave sick for last)

Disinfect vehicles before driving up to Disinfect vehicles before driving up to facilityfacility

People Management (cont.)People Management (cont.)

Visitor parking at periphery of facility groundsVisitor parking at periphery of facility grounds Restrict facility access to a minimum number of Restrict facility access to a minimum number of

peoplepeople Minimize number of tours and limit to small, Minimize number of tours and limit to small,

easily managed groupseasily managed groups Maintain log bookMaintain log book Visitors (not at aquaculture facility w/in past 48 Visitors (not at aquaculture facility w/in past 48

hours) – coveralls over clothing, disinfected hours) – coveralls over clothing, disinfected boots, wash with antibacterial soap for 30 boots, wash with antibacterial soap for 30 secondsseconds

Visitor ControlVisitor Control

People Management (cont.)People Management (cont.)

Visitors (at aquaculture facility w/in past Visitors (at aquaculture facility w/in past 48 hours) – remove clothes, put on 48 hours) – remove clothes, put on coveralls and disinfected boots, wash coveralls and disinfected boots, wash with antibacterial soapwith antibacterial soap

Instruct visitors not to touch, or lean on, Instruct visitors not to touch, or lean on, anything in culture roomanything in culture room

Change footbaths and disinfect floors Change footbaths and disinfect floors after every tourafter every tour

FootbathFootbath

QuarantineQuarantine Planned early in the design of the facilityPlanned early in the design of the facility Separate building, room or area with Separate building, room or area with

independent, isolated culture systemindependent, isolated culture system Q period accounts for incubation and Q period accounts for incubation and

development times for targeted pathogensdevelopment times for targeted pathogens Water temperature kept at upper end of Water temperature kept at upper end of

fish species optimum range to speed up fish species optimum range to speed up pathogen life cyclespathogen life cycles

Quarantine (cont.)Quarantine (cont.)

Observe new arrivals for abnormalities in Observe new arrivals for abnormalities in appearance and behavior, sample and appearance and behavior, sample and examineexamine

Throughout Q period, sample normal and Throughout Q period, sample normal and abnormal fish, examineabnormal fish, examine

Hold fish at culture densities they will Hold fish at culture densities they will encounter in production systemencounter in production system

Quarantine (cont.)Quarantine (cont.)

Wash hands and arms before going between Wash hands and arms before going between quarantine and production area. Disinfect quarantine and production area. Disinfect footware. Change clothing.footware. Change clothing.

Save work in Q area as last element of the work Save work in Q area as last element of the work dayday

Use Q equipment only in the Q areaUse Q equipment only in the Q area Acclimate fish to production system water by Acclimate fish to production system water by

introducing it to quarantine before transfer out introducing it to quarantine before transfer out of quarantineof quarantine

II. Practices to Reduce II. Practices to Reduce Pathogen SpreadPathogen Spread

Meticulous husbandryMeticulous husbandry

HusbandryHusbandry

Install deep foot baths, clean and change Install deep foot baths, clean and change frequentlyfrequently

Wash hands and arms before entering Wash hands and arms before entering fish culture area and as change work with fish culture area and as change work with groups of fishgroups of fish

Easily accessible disinfectant and rinse Easily accessible disinfectant and rinse areas (e.g., for buckets, nets, meters)areas (e.g., for buckets, nets, meters)

Disinfection areaDisinfection area

Husbandry (cont.)Husbandry (cont.)

Store clean equipment in a clean areaStore clean equipment in a clean area Meticulous husbandry proceduresMeticulous husbandry procedures Even for recycle loop, treat each tank as Even for recycle loop, treat each tank as

a discrete rearing unit, minimize a discrete rearing unit, minimize potential for cross-contaminationpotential for cross-contamination

Disinfect tanks and equipment before use Disinfect tanks and equipment before use with a different group of fishwith a different group of fish

Husbandry (cont.)Husbandry (cont.)

Regard floor as contaminated, manage Regard floor as contaminated, manage accordinglyaccordingly

Clean floors frequentlyClean floors frequently Inspect and clean all parts of system Inspect and clean all parts of system

frequentlyfrequently Exclude pets, rodents, birds, other Exclude pets, rodents, birds, other

vertebrates and insects from culture areavertebrates and insects from culture area

DefinitionsDefinitions Surfactant – 'SURFace ACTive AgeNT' - a molecule that Surfactant – 'SURFace ACTive AgeNT' - a molecule that

lowers suface tension; contain both hydrophobic and lowers suface tension; contain both hydrophobic and hydrophilic components so are semi-soluble in both organic hydrophilic components so are semi-soluble in both organic and aqueous solvents; the hydrophobic component sticks to and aqueous solvents; the hydrophobic component sticks to grease and dirt while the hydrophilic section sticks to the grease and dirt while the hydrophilic section sticks to the water; active ingredient in soapwater; active ingredient in soap

Disinfectant – eliminates virtually all recognized pathogenic Disinfectant – eliminates virtually all recognized pathogenic microorganisms; an agent that kills or inactivates >99.99% microorganisms; an agent that kills or inactivates >99.99% of disease causing microorganisms, may not kill sporesof disease causing microorganisms, may not kill spores

Sanitizer – an agent that decreases the load of Sanitizer – an agent that decreases the load of microorganisms (not necessarily pathogenic)microorganisms (not necessarily pathogenic)

Surfactant ExampleSurfactant Example ““Simple Green”Simple Green”

Cleaner and degreaserCleaner and degreaser Listed as nonhazardous, non-mutagenic, non-Listed as nonhazardous, non-mutagenic, non-

carcinogeniccarcinogenic On a scale of 1 to 4, ranked as 1 for slight health On a scale of 1 to 4, ranked as 1 for slight health

hazard because it can be a mild eye irritant (mucous hazard because it can be a mild eye irritant (mucous membrane irritation concentrate mist)membrane irritation concentrate mist)

No special ventilation is required during useNo special ventilation is required during use Meets EPA and OECD recommendations for ready Meets EPA and OECD recommendations for ready

biodegradability; practically non-toxic per EPA’s biodegradability; practically non-toxic per EPA’s aquatic toxicity scaleaquatic toxicity scale

Components on TSCA Chemical Substance InventoryComponents on TSCA Chemical Substance Inventory

DisinfectantsDisinfectants

Factors affecting disinfection processFactors affecting disinfection process TypeType ConcentrationConcentration TemperatureTemperature Contact TimeContact Time pHpH Presence of soil/organic matterPresence of soil/organic matter Number of organismsNumber of organisms Type and growth phase of organismType and growth phase of organism

IodophorIodophor

Broad spectrum Broad spectrum (inactivates IPNV)?(inactivates IPNV)?

NoNo

Inactivated by soil/organic Inactivated by soil/organic matter?matter?

Yes, but turns yellow & is more stable Yes, but turns yellow & is more stable than chlorinethan chlorine

Non-toxic fish?Non-toxic fish? Depends on dilutionDepends on dilution

Non-toxic humans?Non-toxic humans? Skin and eye irritationSkin and eye irritation

Corrosive?Corrosive? SlightlySlightly

Surfactant activity?Surfactant activity? NoNo

Leaves active residue?Leaves active residue? YesYes

Stable?Stable? Dissipates slowlyDissipates slowly

Tests for active chemical Tests for active chemical residues?residues?

Test stripsTest strips

Safe for environmentSafe for environment RegsRegs

Quaternary Ammonium Compounds Quaternary Ammonium Compounds (QACs)(QACs)


NoNo

Inactivated by Inactivated by soil/organic matter?soil/organic matter?

Moderately stableModerately stable


Non-toxic humans?Non-toxic humans? Corrosive to skin and eyes; Irritation of Corrosive to skin and eyes; Irritation of respiratory tract; headache, drowsinessrespiratory tract; headache, drowsiness

Corrosive?Corrosive? NoNo

Surfactant activity?Surfactant activity? YesYes

Leaves active Leaves active residue?residue?

YesYes

Stable?Stable? YesYes

Tests for active Tests for active chemical residues?chemical residues?


Safe for environmentSafe for environment RegsRegs

Hypochlorite (HTH)Hypochlorite (HTH)Broad spectrum Broad spectrum (inactivates IPNV)?(inactivates IPNV)?

YesYes


YesYes

Non-toxic fish?Non-toxic fish? Extremely toxic at low concentrationsExtremely toxic at low concentrations

Non-toxic humans?Non-toxic humans? Dust causes skin, eye, digestive tract and Dust causes skin, eye, digestive tract and respiratory burnsrespiratory burns

Corrosive?Corrosive? Yes, to metals and plasticsYes, to metals and plastics

Surfactant activity?Surfactant activity? V. slightV. slight

Leaves active residue?Leaves active residue? NoNo

Stable?Stable? No, dissipates rapidlyNo, dissipates rapidly



Safe for environmentSafe for environment Regs (must be neutralized with sodium Regs (must be neutralized with sodium thiosulfate)thiosulfate)

Virkon-SVirkon-S(potassium monopersulfate)(potassium monopersulfate)


YesYes


??


Non-toxic humans?Non-toxic humans? As powder can be respiratory and eye As powder can be respiratory and eye irritantirritant

Corrosive?Corrosive? To metals but not nettingTo metals but not netting

Surfactant activity?Surfactant activity? Yes (including bacterial biofilms)Yes (including bacterial biofilms)

Leaves active residue?Leaves active residue? ??

Stable?Stable? Dissipates Dissipates veryvery slowly slowly


??

Safe for environmentSafe for environment Regs., breaks down to harmless organic Regs., breaks down to harmless organic saltsalt

CullingCulling

An important strategy to reduce An important strategy to reduce transmission of pathogenstransmission of pathogens

Should include sick (as long as cause is Should include sick (as long as cause is infectious) as well as dead fishinfectious) as well as dead fish

Cull at least once per dayCull at least once per day Fish should be killed humanely, not Fish should be killed humanely, not

allowed to die from suffocationallowed to die from suffocation

Additional StrategiesAdditional Strategies

Changing flow to increase turnover Changing flow to increase turnover ratesrates

Density manipulationDensity manipulation

Culture ActivitiesCulture Activities

Minimize the number of different Minimize the number of different personnel working with a group of fishpersonnel working with a group of fish

Unaffected tanks should be worked on Unaffected tanks should be worked on before affected tanksbefore affected tanks

Care for young fish before older fishCare for young fish before older fish Equipment touching the floor should not Equipment touching the floor should not

contact fish culture watercontact fish culture water Fish that jump from tank to floor should Fish that jump from tank to floor should

be humanely killed, not returned to tankbe humanely killed, not returned to tank

III. Practices to Reduce III. Practices to Reduce Susceptibility to Infection and Susceptibility to Infection and

DiseaseDisease

Strategies for a Strong Immune Strategies for a Strong Immune SystemSystem

Optimum nutritionOptimum nutrition Fish should be from Fish should be from

optimum year class optimum year class brood stockbrood stock

Gentle handling to Gentle handling to reduce stress and reduce stress and injuryinjury

VaccinationVaccination

IV. MonitoringIV. Monitoring

Set up a Set up a monitoring and monitoring and response planresponse plan

Record KeepingRecord Keeping

Used to track changesUsed to track changes Used to improve biosecurity protocolsUsed to improve biosecurity protocols Includes water quality, feed fed, feed lot Includes water quality, feed fed, feed lot

numbers, visitors, number of dead and numbers, visitors, number of dead and culled fish, observations of abnormalities, culled fish, observations of abnormalities, laboratory results, results of treatmentlaboratory results, results of treatment

Monitor Water Quality!Monitor Water Quality!

Know normal vs. abnormal Know normal vs. abnormal behavioral and physical signs for behavioral and physical signs for

stress and illnessstress and illness

Behavioral and Physical Signs for Behavioral and Physical Signs for Stress/IllnessStress/Illness

MovementMovement Weak, erratic, lethargic swimmingWeak, erratic, lethargic swimming Abnormal reaction to external stimuli such as Abnormal reaction to external stimuli such as

noise or movementnoise or movement Scratching, flashing, rubbing against tank walls Scratching, flashing, rubbing against tank walls

or bottomor bottom Twitching, darting, spinning or jumping out of Twitching, darting, spinning or jumping out of

waterwater Crowding at inflent water supplyCrowding at inflent water supply Swimming upside downSwimming upside down Gasping at water surfaceGasping at water surface


FeedingFeeding Not feedingNot feeding Reduced feeding (detected by system TAN Reduced feeding (detected by system TAN

and growth curves as well as observation)and growth curves as well as observation) BreathingBreathing

Decreased or increased rate of opercular Decreased or increased rate of opercular movementmovement


Physical ConditionPhysical Condition Visible lesions or soresVisible lesions or sores Cloudy eyes, Cloudy eyes,

protruding eyesprotruding eyes GillsGills swollen, white, swollen, white,

pink or pale red, pink or pale red, eroded, puffy, bloody, eroded, puffy, bloody, brownbrown

Scale lossScale loss Swollen abdomenSwollen abdomen DiarrheaDiarrhea

Excess mucus on Excess mucus on skin/gills (check for skin/gills (check for excess mucus on tank excess mucus on tank screens)screens)

Spots, fungus on skinSpots, fungus on skin Unusual coloration on Unusual coloration on

body surfacebody surface Flared operculaFlared opercula Frayed fins or tailFrayed fins or tail Bubbles in eyes, skin, Bubbles in eyes, skin,

gillsgills

Submersible Biomass ScannerSubmersible Biomass Scanner

VAKI DNG VAKI DNG ((Kópavogur, IcelandKópavogur, Iceland))

Used to track Arctic char size & growth at CFFI.

V. DiagnosisV. Diagnosis

Supplies/Equipment for Fish Supplies/Equipment for Fish Health LaboratoryHealth Laboratory

Compound microscope (with 10X ocular Compound microscope (with 10X ocular and 4X, 10X, and 40X objectives)and 4X, 10X, and 40X objectives)

Slides, cover slipsSlides, cover slips Dissecting kit (for large and small fish)Dissecting kit (for large and small fish) Anesthetic (e.g., tricaine methane Anesthetic (e.g., tricaine methane

sulfonate (MS-222))sulfonate (MS-222))

DiagnosisDiagnosis

Keep accurate records so that an Keep accurate records so that an accurate history can be compiledaccurate history can be compiled

Learn normal and abnormal appearance Learn normal and abnormal appearance and behaviorand behavior

Evaluate water qualityEvaluate water quality Learn skin scrape and gill biopsy Learn skin scrape and gill biopsy

techniques to identify parasitestechniques to identify parasites Find an aquaculture veterinarianFind an aquaculture veterinarian

DiagnosisDiagnosis

An accurate diagnosis is essentialAn accurate diagnosis is essential Determines treatment regimen (whether, and Determines treatment regimen (whether, and

which, chemotherapeutants should be used)which, chemotherapeutants should be used) Treatment based on hunches results in Treatment based on hunches results in

wasted time and money and further wasted time and money and further degradation of the fishdegradation of the fish

Incorrect diagnosis prevents development of Incorrect diagnosis prevents development of an effective strategy to prevent recurrencean effective strategy to prevent recurrence

TreatmentTreatment Disease from water quality more likely in a Disease from water quality more likely in a

biosecure recirculating system (slow turnover biosecure recirculating system (slow turnover rate)rate)

If chemical treatment is necessary, effect on If chemical treatment is necessary, effect on biofilter must be considered (Table 13.3) (design biofilter must be considered (Table 13.3) (design system for biofilter bypass during treatment)system for biofilter bypass during treatment)

When treating the whole system, slow turnover When treating the whole system, slow turnover rate means chemical might need to be applied at rate means chemical might need to be applied at a lower concentration for a longer perioda lower concentration for a longer period

Take individual tanks off-line for bath or flow-Take individual tanks off-line for bath or flow-through treatment through treatment

Case Study #1Case Study #1

Recirculating salmonid facilityRecirculating salmonid facility Specific-pathogen-free eggsSpecific-pathogen-free eggs

Biosecurity recommendations included disinfection of Biosecurity recommendations included disinfection of eggs with iodophor upon arrival from suppliereggs with iodophor upon arrival from supplier

Specific-pathogen-free water supplySpecific-pathogen-free water supply Design criteria included clean outsDesign criteria included clean outs

Attention to biosecurity appeared to be Attention to biosecurity appeared to be excellent but after one year, saw system-wide excellent but after one year, saw system-wide fungal infections and upon routine inspection fungal infections and upon routine inspection fish were infected with fish were infected with Aeromonas Aeromonas salmonicidasalmonicida (furunculosis) (furunculosis)

Case Study #1 (cont.)Case Study #1 (cont.)

RecommendationsRecommendations Fungi growing on solids substrates, so system Fungi growing on solids substrates, so system

maintenance is overdue – it’s time to get into the maintenance is overdue – it’s time to get into the cleanouts and get the solids out of the system, also, use cleanouts and get the solids out of the system, also, use formalin to treat affected fish.formalin to treat affected fish.

Some of the clean outs were not installed, others were concreted Some of the clean outs were not installed, others were concreted in. As a result, needed to try to access the pipes from hard-to-in. As a result, needed to try to access the pipes from hard-to-reach areas – continually coping with chronic, low-level fungal reach areas – continually coping with chronic, low-level fungal infections in the system – install cleanouts after system builtinfections in the system – install cleanouts after system built

Regarding the furunculosis bacteria – recommendations Regarding the furunculosis bacteria – recommendations to disinfect eggs upon arrival were not followed because to disinfect eggs upon arrival were not followed because “the supplier disinfected them before shipping” – they are “the supplier disinfected them before shipping” – they are now disinfecting eggs upon arrivalnow disinfecting eggs upon arrival

Case Study #2 Case Study #2 (or, if we do everything you say, (or, if we do everything you say,

will we experience disease will we experience disease outbreaks?)outbreaks?)

FI research system – a biosecure systemFI research system – a biosecure system Spring water supplySpring water supply No infectious disease problems except No infectious disease problems except

chronic, recurring respiratory diseasechronic, recurring respiratory disease A “new” pathogen – chlamydia-like/rickettsia-A “new” pathogen – chlamydia-like/rickettsia-

like bacteria that infects gill cellslike bacteria that infects gill cells Identification of organism, development of Identification of organism, development of

prevention and control strategies are in prevention and control strategies are in progressprogress

Current/Future Issues in Current/Future Issues in Biosecurity of Recirculating Biosecurity of Recirculating

SystemsSystems The safety of “disease-free” ground water The safety of “disease-free” ground water

suppliessupplies Opportunistic pathogens present in Opportunistic pathogens present in

recirculating systems that come from the recirculating systems that come from the fish or from the environmentfish or from the environment

Biosecurity programs should be dynamic, re-evaluate and

change as necessary

biosecurity and fish health management for recirculating systems

Documents

columnaris disease

coldwater disease

bacterial gill disease

severity of disease

fish health management

individual tanks

vibrationarrange tanks

catastrophic losses