PROPOSED IHNV BROODSTOCK SAMPLING PROGRAM FOR IDFG STEELHEAD

PROPOSED IHNV BROODSTOCK SAMPLING PROGRAM FOR IDFG

STEELHEAD

DOUG MUNSON And

DR. PHIL MAMER

LSRCP MEETING 2012

CONVERSATIONS WITH EXPERTS

• MOVE EGGS NOT FISH…SCOTT LAPATRA• IF YOU HAVE IHN, YOU HAVE A BIO-SECURITY

PROBLEM…SCOTT LAPATRA AND GAEL KURATH

• TO DATE THERE IS NO EVIDENCE OF VERTICAL TRANSMISSION OF IHN, THE PROBLEM IS YOU CANNOT PROVE A NEGATIVE…SCOTT AND GAEL

SUSCEPTABLE SPECIES(to natural infection)

All Pacific Salmon (Sockeye, Chinook, Coho, Pink, Chum, (Masu & Amago)Steelhead/rainbow troutAtlantic salmonBrook trout*Brown trout*Cutthroat trout*

*More resistant to clinical disease

“U” cladeSockeye Salmon

“M” cladeSteelhead/Rainbow

“L” cladeChinook Salmon

INFECTIOUS HEMATOPOIETIC NECROSIS VIRUS (IHNV)

• Native to salmonids in NW North America.

• Rhabdovirus (bullet-shaped, ssRNA).

• Attacks the hematopoietic tissues of the kidney.

• Transmission fish-to-fish and via egg surface contamination.

TRANSMISSION• CLINICALLY INFECTED AND COVERT CARRIERS

– CULTURED, FERAL, AND WILD• VIRUS IS SHED

– URINE, OVARIAN FLUIDS, EXTERNAL MUCUS– KIDNEY, SPLEEN, OTHER INTERNAL ORGANS– GILL AND BRAIN

• VECTORS– INSECTS, ANNELIDS, CRUSTACEANS– WATER DROPLETS (FOMITE) AND EQUIPMENT

• CLINICAL OUTBREAKS AT 10⁰C– NOT NATURALLY ABOVE 15⁰C

LethargyDarkened colorPop-eye (exophthalmia; often with hemorrhage)

Anemia (loss of red color in gills and internal organs)

Spleen normal size Mortality rate often

exponential

CLINICAL SIGNS OF IHN

DIAGNOSTIC TOOLS

DIAGNOSTIC TOOLS

PCR CONFIRMATION

OregonIdaho

Washington

Salm

onR

.

Snake R.

Columbia R.

0 25

50 75 100 km

Paci

fic O

cean

SA

OX

RR

MC SF PA

POCW

DW

RRCR

EF

OregonIdaho

Washington

Salm

onR

.

Snake R.

Columbia R.

0 25

50 75 100 km

Paci

fic O

cean

SA

OX

RR

MC SF PA

POCW

DW

RRCR

EF

Management for IHN

• Avoidance– Broodstock sampling• Test all parent females at spawning and cull eggs from

positive individuals.– Egg disinfection• Iodophor is an effective surface disinfectant for both

water hardening and eyed stages.– Isolation/Quarantine• A pathogen-free water source is critical!• Do not bring a source onto your hatchery.

Management for IHN

• Successful example:– Clearwater Hatchery: test 100% brood, disinfect,

and quarantine.– Water source without anadromous fish.

• Moderate success:– Niagara Springs Hatchery: test and disinfect, but

isolation is not always complete.– IHN outbreaks usually in fry shipments.

Culture Opportunities• Bio-Security/Integrated Fish

Health Management

• Disease free water supply

• Disinfection and quarantine

• Compartmentalization: spread the risk within and between facilities

• Hatchery personnel charged with decision to destroy infected groups

CLEARWATER STEELHEAD

• RECEIVE ONLY EGGS FROM IHN NEGATIVE FEMALES

• IODOPHOR GREEN EGGS AT SPAWNING• IODOPHOR EGGS UPON ARRIVAL AT

CLEARWATER• TO DATE, NO DETECTIONS OF IHN IN

JUVENILE STEELHEAD

BIO-SECURITY

• BROODSTOCK TESTING• IODOPHOR DISINFECTION OF EGGS

– ADDITIONAL DISINFECTION IF EGGS ARE MOVED• TRANSPORT EGGS• CERTIFICATION TESTING BEFORE TRANSPORT OF FISH

– Phase out• DISINFECTION OF EQUIPMENT AND RACEWAYS

– FOOT BATHS AND HAND SANITIZER• PERIODIC JUVENILE INSPECTION• BIO-SECURITY AUDITS

PREDICTIONSVirus will become widely established in the basinAdditional host species will become involvedVirus will persist in low-level carriers much of the yearStressors will exacerbate latent infections and diseaseDisease will occur on periodic basis – especially in the spring Recovered fish will become immune, leading to disease occurring primarily in younger age classesDisease will have population-level effects for some speciesDisease will become less explosive in most yearsDisease will impact both management and commercial activitiesIt will be important to prevent the spread of the virus to other freshwater systems in the U.S. and Canada, as well as to the commercial aquaculture industry

CONCLUSIONS

• APPLY CLEARWATER PLAN THOUGHOUT IDFG– MORE FISH TO SAMPLE AND SPAWN– MORE HOURS SPAWNING, SAMPLING, PROCESSING– MORE $ (INCREASE COST OF DOING BUSINESS)

• MOVE EGGS – CAN DISINFECT EGGS– CANNOT DISINFECT FISH

• MAINTAIN HIGH LEVEL BIO-SECURITY

MORE HEALTHY FISH TO RELEASE

MORE HEALTHY FISH RETURNING

SO MANY, EVEN TRAVIS WILL BE SUCCESSFUL

NO EXOTIC IHNV TYPES INTO HAGERMAN VALLEY