Download ISA Virus Regional Contingency Plan - NWIFC Access

Contingency Plan in Response to the Confirmed Finding of Infectious Salmon
Anemia Virus in the Pacific Region of the United States
States of Washington and Alaska, the Northwest Indian Fisheries Commission, and U.S.
Departments of Agriculture (APHIS), Interior (USFWS), and Commerce (NOAA)
February 2013
Background
Infectious salmon anemia (ISA), caused by the virus of the same name, is a serious infectious
disease of farmed Atlantic salmon (Salmo salar). The disease is known to occur in Maine, parts
of Atlantic Canada, Europe, and Chile. Molecular evidence of infectious salmon anemia virus
(ISAV) was reported from wild juvenile sockeye salmon (O. nerka) in marine waters near Rivers
Inlet, British Columbia, Canada. This report was made through the Canadian media on October
17, 2011. Further, a report was made on October 29, 2011 in the New York Times of a similar
finding in a wild, adult coho salmon (O. kisutch) from the Fraser River system.
These suspect findings are of special concern because it would be the first finding of this virus in
the Northeast Pacific Ocean. The Canadian Food Inspection Agency (CFIA), the competent
federal authority in Canada, has investigated these ISAV reports and was unable to confirm the
presence of ISAV in the samples mentioned above. To date, there is no confirmed finding of
ISAV in the Pacific Ocean by either the US or Canada. ISA is a serious infectious disease of
farmed Atlantic salmon and is highly contagious within farmed settings. Historic outbreaks in
farms have resulted in massive mortalities in that species. However, ISAV has never been
known to cause disease in wild Pacific salmon anywhere in the world. The epidemiology of ISA
is now better understood and timely action has been shown to reduce or prevent significant
mortality in an infected farm population.
Currently, there are no confirmed findings of either virulent (HPR deleted) or avirulent (nondeleted HPR0) strains of ISAV in the Pacific Coast of North America. Surveillance is currently
underway in both countries to determine the presence/absence of either strain of ISAV. The
purpose of this plan is to reach consensus on the response by management entities should ISAV
be confirmed in the Pacific region of the U.S.
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Responses to various scenarios of ISAV detections (both virulent and avirulent strains) in
Pacific Salmon in the Pacific Northwest
West Coast Pacific salmon and trout are being collected to survey for Infectious salmon anemia
virus (ISAV). Samples collected for this screening program are not associated with disease in the
fish. A highly sensitive laboratory technique called polymerase chain reaction (PCR) is being
used to screen for molecules associated with ISAV. PCR tests can give false positive results and
so additional testing (including sequencing and virus isolation) will be required to confirm any
PCR finding. Any fish population testing positive for ISAV molecules will be subjected to
enhanced surveillance. The following is a brief description of the various testing outcomes for
samples:
 Suspect sample: A screening test has been performed by approved methods at one of the
participating laboratories, but the results of the testing cannot confidently be classified as
either a positive or negative for ISAV. A "suspect" result means that this sample will have
additional tests performed on it. This situation is similar to many cancer screening tests
performed as part of a preventive medicine program on individuals with no signs of the
disease. A suspect finding on the screening test identifies which individuals need more
thorough testing to determine if the condition is actually present in the individual or not.
 Presumptive positive sample: Further analysis has occurred on this sample at the U.S.
Department of Agriculture National Reference Laboratory using additional tests. A
presumptive positive finding means results from all the tests performed on the sample
indicate that viral molecules are present but the virus has not been isolated from the sample.
 Confirmed positive sample: The ISA virus has been detected on a molecular basis and the
virus cultured from the sample in the laboratory. This meets the internationally-recognized
criteria for a positive finding of this virus.
The following are definitions for “hatchery” and “wild” salmonid stocks:
 Hatchery stock – fish in fresh or seawater that are either captive or free ranging and have a
pedigree of an artificially cultured fish that may be distinguished by genetic markers, fin clip,
otolith mark, scale growth patterns, coded wire or other type tag.
 Wild stock – a stock of fish that is free ranging in fresh or seawater that has not been captive
or propagated artificially and has no anthropogenic mark of identification but can usually be
distinguished by genetic methods.
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Management Responses to the various testing outcomes:
1. Hatchery or wild population is suspect for ISAV:
a. Criteria: A tissue sample from at least one fish in a wild or hatchery population
has had a “suspect” screening test result using the validated ISAV real time RTPCR screening assay but confirmatory PCRs and virus isolation in cell culture
have not yet been done. The finding is not associated with any clinical disease or
mortality in the population.
b. Response:
i. The U.S. Department of Agriculture Animal and Plant Health Inspection
Service (APHIS) Area Veterinarian In-Charge (AVIC) and the submitter
will be notified by the approved screening laboratory.
ii. Additional testing will be done on that sample at the approved screening
laboratory and at the National Veterinary Services Laboratories (NVSL).
iii. The duplicate sample from the suspect fish will be sent to NVSL for
additional testing.
iv. Remaining duplicate samples from other fish in the population that tested
negative will be sent to the Western Fisheries Research Center to test for
other viruses including some closely related to ISAV.
v. No control action will be taken on the population until confirmatory
testing determines whether some form of ISAV is present in the sample
(see presumptive or confirmed sections).
c. Rationale: The highly sensitive PCR screening assay used in the ISAV
surveillance effort can give false positive results so additional tests are required to
confirm the presence of ISAV in the sample
2. Hatchery population is presumptive for the HPR0 strain of ISAV:
a. Criteria: The HPR0 strain of ISAV is identified by PCR and sequencing (cannot
isolate this strain in cell culture) in at least one fish in a hatchery population. No
clinical disease or increased mortality is associated with this finding.
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. No control action to be taken on the population.
iii. Increased surveillance of the hatchery population will occur.
c. Rationale: An avirulent presumed ancestral strain of ISAV that cannot be
cultured and that is not causing any mortality poses low risk to native fish
populations. This strain may exist in various wild stocks of salmonids and
possibly is an indigenous virus.
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*Note: HPRO strains will not replicate or grow in cell culture so the final criteria of
confirmed cannot be achieved.
3. Hatchery population is presumptive for a HPR deleted strain of ISAV but there is
no associated mortality or clinical disease signs in the population:
a. Criteria: An HPR deleted strain of ISAV is identified by PCR and sequencing (but
no virus isolation) in at least one fish in a hatchery population. No clinical disease
or mortality is associated with this finding.
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. No control action to be taken on the hatchery population.
iii. Increased surveillance of the hatchery population will occur.
c. Rationale: Detection of the virus by only molecular methods and the absence of
any clinical disease in the population would indicate that there is a minimal
disease risk to the hatchery population. Increased surveillance will help us better
understand the source and evolution of this isolation.
4. Hatchery population has a confirmed detection of a HPR deleted strain of ISAV but
no evidence of disease in the population.
a. Criteria: An HPR deleted strain of ISAV is isolated in cell culture and confirmed
by PCR and sequencing in at least one fish in a hatchery population. However,
there is no clinical disease or mortality associated with this finding.
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. Hatchery to implement temporary bio-security measures that may include
quarantine of all stocks of fish at that hatchery to contain the spread of the
virus.
iii. Emergency meeting of federal, state, and tribal fishery resource managers
to assess the risks this finding poses to the resource and whether further
management actions including continuation of the quarantine should be
taken. If the confirmed detection is from private sector facilities, that
meeting will also include representatives from the affected company.
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iv. Increased surveillance of the hatchery and wild populations in the
watershed will occur.
c. Rationale: Many hatchery stocks come from wild stocks which certainly mix with
other wild stocks both in the ocean, estuarine and freshwater environments.
Further research will be necessary to determine if this virus is confined to one
stock and potentially exotic or widespread and possibly indigenous.
5. Hatchery population has a confirmed detection of a HPR deleted strain of ISAV
that is causing clinical disease in the population:
a. Criteria: An HPR deleted strain of ISAV is isolated and confirmed by PCR and
sequencing in at least one fish in a hatchery population. The virus is determined to
be clearly causing associated clinical disease (pathology, immuno-histopathology)
and mortality.
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. Hatchery to implement bio-security measures including quarantine of all
stocks of fish at that site to contain the spread of the virus.
iii. Emergency meeting of federal, state, and tribal fishery resource managers
to assess the risks this finding poses to the resource and to determine
further management actions that should be taken. Strong consideration
should be given to quarantining of the hatchery, destruction of the infected
hatchery population, and hatchery disinfection. If the confirmed detection
is from private sector facilities, that meeting will also include
representatives from the affected company.
iv. Further epidemiological investigation and research is necessary in a
controlled laboratory setting to determine salmonid species susceptibility
and pathogenicity of virus and increased surveillance at facility and
exposed populations.
v. Increased surveillance for the virus in hatchery and wild populations in the
watershed will occur.
c. Rationale: This situation demonstrates that a previously thought to be exotic
pathogenic virus is present in Pacific salmon and all appropriate measures should
be taken to contain its spread until surveillance and research efforts can determine
its range and risk it poses to wild and hatchery populations.
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6. Wild population is presumptive for HPR0 strain of ISAV:
a. Criteria: A non-deleted HPRO strain of ISAV is identified by PCR and
sequencing (but no virus isolation) in at least one fish in a wild population. No
clinical disease or increased mortality is associated with this finding
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. No control action to be taken on the population.
iii. Increased surveillance of both hatchery and wild populations in that
watershed will occur.
c. Rationale: A presumed ancestral strain of ISAV that cannot be cultured and that is
not causing any mortality poses low risk to native fish populations. This strain
may exist in various wild stocks of salmonids and possibly is an indigenous virus.
7. Wild population is presumptive for a HPR deleted strain of ISAV but there is no
associated mortality or clinical disease signs in the population:
a. Criteria: A HPR deleted strain of ISAV is identified by PCR and sequencing (but
no virus isolation) in at least one fish in a wild population. No clinical disease or
mortality is associated with this finding.
b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. No control action to be taken on the wild population.
iii. Increased surveillance of both the hatchery and wild population in the
watershed will occur.
c. Rationale: No evidence that this detection presents a risk to wild or hatchery
salmon populations. Further studies are needed to determine if other species are
susceptible to this virus.
8. Wild population has a confirmed detection of a HPR deleted strain of ISAV.
a. Criteria: An HPR deleted strain of ISAV is isolated in cell culture and confirmed
by PCR and sequencing in at least one fish in a wild population. This finding may
or may not be associated with clinical disease and mortality in the affected
population.
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b. Response:
i. The AVIC and the submitter will be notified by the approved screening
laboratory. The submitter will be responsible for notifying regional natural
resource fishery agencies per agreed upon notification requirements in
their respective disease control policies.
ii. Emergency meeting of federal, state, and tribal fishery resource managers
to assess the risks this finding poses to the resource and to determine what,
if any, management actions can be taken to prevent its spread.
iii. Increase surveillance efforts of hatchery and wild populations in the
watershed to better understand its distribution.
iv. Design and conduct an investigation to better understand the fish health
risks this virus poses to hatchery and wild population in the Pacific
Northwest.
c. Rationale: The response to this finding is to develop a better understanding of the
nature and distribution of this isolation while acknowledging that there is no
known or proven eradication methodology for a pathogen in an open-water
situation.
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