Infectious Salmon Anemia (ISA)

Development and application of a national contingency plan for emergencies in aquaculture – Experience of a country

Michael David, MS, VMD, MPH USDA APHIS Veterinary Services

Mazatlán, Mexico November 11-12, 2008

Acknowledgements

• Dr. Gary Egrie – Aquaculture Specialist, APHIS/VS, Maryland

• Dr. Steve Ellis – VMO, APHIS/VS, Maine

• Ms. Teresa Robinson – Biologist, APHIS/VS, Maine

• Other State and Industry

Maine

Isolated Broodstock

Lethal spawning

Collecting Eggs & Milt

Broodstock Sampling

Disinfection & Hardening

Egg trays

Hatchery Tanks

Smolt fieldHatch house

Smolt Transport

SmoltTransfer

Harvesting

Infectious Salmon Anemia

Epidemiology• Virus shed in body excretions (feces, urine, mucus)• Transmission

– Ingestion of contaminated tissues/fluids– Physical contact– Sea lice

• If uncontrolled, it will spread from site to site• Onset of clinical disease affected by:

– Length of time fish have been in saltwater– Water temp– Vx status– Sea lice (copepod) load– Nutrition– Immune system status– Site management procedures

Clinical signs

• lethargy • protruding eyes • pale gills

•severe anemia   • swelling of the spleen• swelling and hemorrhaging in the kidney and other organs• darkening of the posterior gut  • fluid in the body cavity 

and Gross pathology

Cobscook Bay: 2001 detection

•2001: detection of ISA and 1 M fish depopulated•Jan 2002: ISA program implemented•Feb 2002: 1.6 M add’l fish depop

•Completes depop in Cobscook Bay

Cleaning & Disinfection

Management of outbreak

Outbreak and its response

• May 2002: restock sites

• May 2002 – May 2003: 13 months of negative monthly samples

• June 9 2003: Site - samples collected 1st cage

• June 12 2003: positive test results confirming ISAV infection (i.e. 2

fish by 2 tests in one cage)

• June 18 2003: completion of fish removal 1st cage

• June 25 2003: samples collected 2nd cage

• July 1 2003: positive test results confirming ISAV infection in 2nd

cage

• July 6 2003: completion of fish removal 2nd cage

ISA outbreak (2002-2006)

ISA Confirmed Cages 2002 - 2006

0

1

2

3

4

Month & Year

# o

f c

ag

es

0

1

2

3

4

Jun-

03

Sep-0

3

Dec-03

Mar

-04

Jun-

04

Sep-0

4

Dec-04

Mar

-05

Jun-

05

Sep-0

5

Dec-05

Mar

-06

# o

f ca

ges

2006YC - 1-3 month fallow for

the sites in ME & NB

Spring 2002, new smolts stocked in

lower part of bay

Spring 2003, smolts

stocked in upper part of

bay

March 2004, all 2002YC confirmed sites out of

water

First confirmed ISA positive cage of the

2002YC

First confirmed ISA positive cage of the

2003YC

First confirmed ISA positive cage of the

2004YC

Timeline of ISA Confirmed Cages 2002 - 2006

August 2005, all 2003YC confirmed sites out of

water

March 2006, all 2004YC

sites out of water

No 2005YC fish in Cobscook Bay

No ISA confirmed cages in the 2006YC fish

Spring 2004, smolts

stocked in lower part of

bay

Response and actions taken

• Increased sampling frequency to weekly on affected sites, biweekly on other sites in the bay

• Collected viral samples from fish in cages with a previous PCR+ result

• Removed cages with positive test results, whether or not confirmed

Example of aggressive cage removal

• Positive PCR results Aug7, Aug11, Aug12 & Aug15/2003

• No corroborating IFAT tests

• Clinical signs of disease observed

• Cage removed voluntarily on Aug22/2003

• Cage was confirmed positive on Sep12/2003 due to positive results of viral samples taken Aug12 & Aug15

• Three weeks less viral exposure to other cages

Chronology of events

• 1996: detected in New Brunswick, Canada• 2001: first identified in Cobscook Bay, Maine

– Industry voluntarily depopulates affected sites– Sites allowed to fallow for 3 months

• 2002: May – new smolts stocked• 2003: June – two cages positive at two sites• Sep 2003 – Feb 2006: 40 more cages positive• Mar 2006 – Apr 2006: USA-Canada coordinated fallowing• 2006: May – new smolts stocked

– No infection/disease for more than 2 years– Fish to be harvested Feb 2009

• 2009: Spring – new smolts to be stocked

Biosecurity

Biosecurity Practices• Implement mandatory third-party biosecurity audits of

farms and vessels• Have dedicated site-specific personnel, equipment &

vessels• Disinfect all aquaculture equipment after use• Disinfect crew and visitor gear before and after transport

to a site• Disinfect mort divers between cages and at the end of

the dive– Have dedicated site-specific gear for each diver and cage-

specific dive bags• Disinfect boat and mort tender gear at the end of each

dive• Clean and disinfect vessels before being moved between

zones or across the border

Iodophor scrub station

Disinfection after a dive

Boot disinfection on vessel

Disinfection of diver between cages

Management Practices• Establish management zones

– 2006: new management zones established based on hydrographic models of tidal exchange between sites on both sides of the border

• Fallow all sites in a management zone for one to three months

• Restrict movement of vessels, equipment and personnel between sites and management zones

• Prohibit movement of fish between sites• Selective age-grouping of fish by zone• Monitor sea lice periodically• Conduct monthly surveillance for ISAV• Depopulate affected cages

Bay Management Zonation

From this… … to this

Canadian standards

USA standards

Industry

• Held regular meetings between USDA APHIS and authorities from New Brunswick, Canada (starting in 2003) to discuss infection status, program goals and collaboration strategies. – Also held meetings with state government officials,

industry managers and veterinarians. • Visited sites, processing plants, and feed

companies• Result of meetings:

– Improved ISA control efforts on both sides of the border.– Improved communication, data-sharing and cooperation.– Improved management strategies.

Collaboration & Program Harmonization

Infectious Salmon Anemia Program

• ISA was the first aquatic disease triggering USDA/APHIS intervention– Resulted in establishment of an aquatic health program

• Formed small committee to establish the ISA Program Standards – (USDA, State, industry and aquatic health professionals)– Used Canadian policies and experience and Norwegian

epidemiologic findings as basis of ISA standards

• Shared resources– Funding: USDA ISA emergency funding (December 2001)

• No appropriated funding

– Personnel: State partner, DMR, lease site and quarantine authority, vessel movement control and enforcement capabilities

Seven Components

• Surveillance• Testing• Disease reporting• Disease control and

biosecurity• Quarantine• Depopulation• Partial compensation

Next steps …

•Common management practices

•Common biosecurity procedures

•Common database

•Health and production data

Muchas Gracias