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1. Spring Viremia of Carp Virus identified
in Washington State
Dr. Tim Miller-Morgan, DVM,
Oregon Sea Grant Extension, College of Veterinary Medicine, Oregon
State University, Newport, OR
Dr. George Sanders, DVM, MS, University of Washington, School of
Medicine and Western Fisheries Research Center, Seattle, WA
Dr. Andrew Goodwin, Ph.D., Aquaculture and Fisheries Center, University
of Arkansas at Pine Bluff, Pine Bluff, AR
Spring Viremia of Carp virus (SVCv) was recently identified in a
backyard koi and goldfish pond located in Snohomish County, Washington
State.
In March 2004, 11 koi and approximately 100 goldfish were purchased
from a local pet store and added to a private back yard koi and
goldfish pond. In the month of April, five of the 11 koi died. The
water temperature in the pond at this time was 67-72°F. The
remaining six koi were euthanized and submitted to the Washington
Animal Disease Diagnostic Laboratory (WADDL) in Pullman, Washington,
where Spring Viremia of Carp (SVC) was diagnosed. The National Veterinary
Services Laboratory (NVSL) in Ames, Iowa confirmed this diagnosis.
At this point, the outbreak appears to be isolated to this one pond
and the pond does not drain to any natural water sources.
Since SVC is a foreign animal disease that must be reported to the
federal government, USDA-APHIS was notified. USDA-APHIS initiated
an investigation and assumed management of this small outbreak.
The owners have been extremely cooperative and the decision was
made to depopulate the remaining koi and goldfish in the pond. Trace-ins
and trace-outs are currently underway from the pet store where the
fish were purchased. This will help APHIS to identify the source
of the virus and other locations that may have received the infected
fish.
This is not the first case of SVCv in North America. A little over
two years ago, SVC was detected on a commercial fish farm on the
East Coast. SVC is a virus recognized by the international animal
health organization, Office International des Epizooties (OIE),
http://www.oie.int , of which the USA is a participating member
country. Because of SVCv foreign animal disease status, the USA
is required to report the outbreak to international authorities.
Discovery of the virus has caused a great deal of hardship for the
farm involved, but by having the virus diagnosed and by calling
in the USDA-APHIS for help, the farmer has made it possible for
the outbreak to be contained and eventually eliminated. If the isolation
had remained undiagnosed and unreported, it probably would have
spread throughout the infected farm, severely impacting production
for the long term. In addition, it would have been spread to other
farms, producing severe losses in cultured and wild minnows, koi,
goldfish, and carp. In the last two years, the virus has been found
in wild fish in Illinois and Wisconsin.
It is important to keep in mind that this carp virus outbreak is
a special case and a special virus. There are dozens of other fish
viruses that are found routinely in fish and that have no reporting
requirements. There is no reason to be concerned that by having
your fish checked for virus infection you are setting yourself up
to be the center of a national fish disease incident. For fish producer/dealers,
the only way to protect your business and your customers is to correctly
identify and handle viral infections when they occur. The problem
with the recent carp virus outbreak was not that it was reported
to USDA-APHIS; the real problem was that a dangerous virus gained
a temporary foothold in the USA. The small outbreak in Washington
serves to emphasize that koi and goldfish hobbyists are not immune
from introducing viral diseases to their ponds and tanks. While
the greater risk currently in the koi hobby is Koi Herpes Virus
(KHV) (see new article to download below), SVC does present a very
real risk to the koi and goldfish hobby. For further information
on Spring Viremia of Carp, please refer to the University of Florida
extension publication on this topic. It may be downloaded at http://edis.ifas.ufl.edu/VM106.
This is an excellent opportunity to
review some general preventive strategies hobbyists and dealers
may use to reduce their risks of introducing these and other diseases
into their fish populations.
- * Always use trusted fish suppliers who will be upfront about
previous fish health problems and will not sell fish that they
suspect or know are sick.
- Have a separate quarantine tank/pond for all new fish. This
tank would optimally have separate nets, totes, and cleaning supplies
that can be disinfected between uses.
- Optimally, quarantine all new fish for at least six weeks (three
weeks at 65F and three weeks at 75F). This allows a period of
time at the optimal temperatures for both SVC and KHV to be detected
in infected fish. If the new fish is a virus carrier, you would
rather have it break with the disease in your quarantine system
rather that in your pond(s) or tank(s) with your other fish.
- Quarantine plants and invertebrates separately from the fish
since many pathogens, parasites, or their intermediates stages
may reside on the plants and invertebrates.
- Remember that during the quarantine period a number of things
should be occurring:
1. The fish are becoming acclimated to new surroundings, water,
food, and your daily patterns.
2. You are actively watching the fish closely for any signs of
disease.
3. You should perform a skin scrape and/or a gill biopsy to see
if the fish is carrying any external parasites that might be introduced
into your other tank(s) or pond(s).
4. Address any disease problems while the fish is in the quarantine
tank, before you add it to your existing population.
5. You should consider adding a potentially expendable fish from
your main tank(s) or pond(s) to keep the new fish company (they
do much better when they are not alone). Since many fish may adapt
to disease agents in their home pond or tank, this allows for
any potential diseases the new fish may be carrying to pass to
this "local" fish or any diseases the "local"
fish may be carrying to pass to this new fish. In this way you
may again identify and treat a disease before you expose the whole
population.
6. Water quality and husbandry for the quarantine system should
be as good if not better than that of your pond(s) or display
tank(s).
Notes:
- Do not mix water from your quarantine tank with your pond(s)
or tank(s).
- If you suspect a viral disease, don't hesitate to contact you
local fish health professional. This may be a local veterinarian
with some fish expertise, veterinary diagnostic laboratory, local
extension agent, or fish pathologist with your local department
of fish and game, or university.
- If you have a large number of new fish and are having significant
losses, consider submitting a few of the sick fish to a veterinary
or aquaculture diagnostic laboratory for a proper disease diagnosis.
Refer to the Ornamental Fish Health Newsletter, 1:1, http://seagrant.oregonstate.edu/extension/miller-morgan.html,
for specific information about submitting fish to a diagnostic
laboratory.
- In many communities there is a local koi and goldfish club
and many of these clubs have volunteer koi health advisors, http://www.akca.org,
who may help you with basic husbandry and health problems. These
individuals are also often aware of local veterinarians and fish
pathologists who will be able to help you with serious disease
problems.
Recent developments have shown that SVCv does pose a risk to hobbyists
as well as well as dealers and producers. Unfortunately, a rapid test
for screening apparently healthy fish is unavailable at this time.
However, knowledge of the disease, some common sense, and relatively
simple preventive measures can reduce the risk of your fish contracting
this disease.
2. Fish Health Management Considerations in Recirculating
Aquaculture Systems, Parts 1, 2, 3 -- Download
Dr. Roy Yanong, an extension veterinarian with the
University of Florida, Tropical Aquaculture Laboratory, recently
published an excellent series of articles on fish health management
in recirculating aquaculture systems. This series does not discuss
specific diseases and treatments; rather, each article addresses
different aspects of basic disease prevention in closed systems.
There is an extensive reference section at the end of each article
for readers who wish to pursue discussed topics in greater detail.
The series is suitable for anyone involved in fish husbandry, but
should be particularly useful to hobbyists with large fish rooms,
dealers, and ornamental fish producers.
3. Tips for Summer Heat
* Jerry Craig, Assistant Manager, The Wet Spot Tropical
Fish, Portland, OR
When summer temperatures rise we receive a number of concerned aquarists
worrying about the well being of their fish. The major concern with
warmer water is the amount of dissolved oxygen available to the
fish. The following suggestions should help keep your fish cool
and happy!
- Check your tank or pond water temperature regularly.
- Reduce feeding levels. When you feed your fish there is a natural
reduction in available oxygen, even during normal temperatures.
Feed when the water is coolest.
- Leave lights off. Aquarium lights, including fluorescents, give
off heat. Eliminating this heat source will help control the temperature.
Lights should only be used sparingly for feeding.
- Partial water changes will help freshen your aquarium by removing
stale oxygen-poor water and adding fresh water, high in dissolved
oxygen. Avoid the temptation to add colder water as this can shock
your fish. Don’t forget to treat any municipal water to remove
chlorine or chloramines before you carry out the water change.
- Add an air stone. Increasing the surface movement of your aquarium
will help increase oxygen levels. Air stones can be added to planted
aquariums, but they will drive off carbon dioxide that your plants
use; therefore, discontinue lighting and CO2 supplements when
aerating.
- Open the lid. Unless you have jumping fish, open the lid and
let some heat dissipate. You can further cool the tank by directing
a fan across the water’s surface. This not only cools the
tank, but cools the room as well.
- One-liter pop bottles filled half-full, frozen, and floated
in the tank, can cool when temperatures get very hot, but be careful
not to cool too fast.
- DO NOT UNPLUG YOUR HEATER. Heaters are thermostatically controlled
and only switch on when the temperature drops below the preset
temperature; however, they do prevent your tank temperature from
dropping when your house cools off.
- When purchasing new fish during the summer months always make
the fish store your last stop so that the fish don’t sit
in the car and cook while you do other errands.
4. Koi Herpes Virus (KHV) Disease
– Download
With the coming of the summer months and warmer water
temperatures, Koi Herpes virus (KHV) is rearing its ugly head again
in ponds around the country. The University of Florida has recently
published a nice article that describes KHV, its signs, how infection
appears to occur, its diagnosis, and some recommendations for prevention.
The article may be downloaded at http://edis.ifas.ufl.edu/VM113
. If you suspect KHV or you would like more information, I would
encourage you to contact the laboratories at the end of the article,
your local fish-friendly veterinarian, myself, a fish pathologist,
or your local veterinary diagnostic laboratory.
5. A Reason for Celebration (and Preparation): The
Aquarium Science Program Completes Its First Year
* Bruce Koike, MS, Director, Aquarium Science Program,
Oregon Coast Community College, Newport, OR
Unbelievably, the first year of Aquarium Science instruction to
the student cohort is completed. Retention of students was high,
considering that of the 19 original students, 17 were actively taking
courses by the end of the spring term. Their evaluation of the Aquarium
Science courses was overall positive, although slight adjustments
to content and delivery methods will be made. These modifications
will be incorporated into the appropriate courses in time for the
next group of Aquarium Science students (Fall 2004). Applications
are still being accepted for this student cohort.
During this first year, students experienced a blend of classroom
instruction and workplace experiences. Key partners in the development
of these future aquarists and husbandry personnel were Oregon Sea
Grant, the Hatfield Marine Science Center, and the Oregon Coast
Aquarium. These institutions and their staff members embraced student
involvement and our appreciation goes out to each of the mentoring
supervisors.
Besides these “workplace classrooms,” students have accompanied
Dr. Miller-Morgan during his veterinary rounds at the Oregon Coast
Aquarium and the Hatfield Marine Science Center. This provided students
with an insight into the complex nature of aquatic animal health
management. Participating students also contributed to the discussion
by making brief presentations about specific disease agents.
On a different plane, Lincoln County voters recently
passed a bond measure ($23.5 million) that supports the construction
of a campus facility for the college. In the current economic and
social climate, this approval is quite a statement by the county’s
population. We look forward to providing improved educational opportunities
-- both to our students and to those who seek to enhance their professional
standing.
6. Upcoming Opportunities
* Northwest Koi and Goldfish Club Annual Show, Portland
Oregon, July 24-25, 2004, http://www.nwkg.org/premier_oregon_fish_show.htm
* Puget Sound Koi Club Annual Young Koi Show, Tacoma, Washington,
August 7-8, 2004, http://www.pskc.org/show.htm
* Seattle Pet Expo, Seattle, WA, August 21-22, 2004, http://www.seattlepetexpo.com/
* Washington Koi and Water Garden Society Annual Show, September,
10-12, 2004, http://washingtonkoi.org/ Greater Portland Aquarium
Society Annual Show, Portland, Oregon, September 11-12, 2004, http://www.gpas.org/
* Marine Aquarium Conference of North America XVI, Boston, Massachusetts,
September, 10-12, http://www.macnaboston.com/
* Sixth International Aquarium Congress - Monterey , California,
December 5-10th, 2004, http://www.iac2004.org/
7. Recent Donations
A big thank-you to Steve Weeks, owner of Pacific Coast
Imports, for the donation of a ½-horse chiller. This chiller
will be used in our upcoming ornamental fish exhibit at the Hatfield
Marine Science Visitor Center.
Anyone who is interested in making monetary donations
to the program to help us offset the costs of maintaining this program
may make checks out to Oregon State University and send them to
me at the address below. You will receive a thank-you letter from
Oregon State University that also documents your donation for tax
purposes. All donations will be used solely for support of this
program and are GREATLY appreciated.
If you are interested in making a donation of goods
or services, please contact me at the numbers and email below and
I can tell you about our current needs.
Articles appearing in this newsletter may be reprinted
in club newsletters, providing proper credit is given to the authors
and the Ornamental Fish Health Newsletter.
*********************************************************************
But if you tame me we shall need each other.
To me, you shall be unique in all the world.
To you, I shall be unique in all the world.
You become responsible, forever, for what you have tamed
-- Anatoine de Saint-Expupery (1900-1944)
Dr. Tim Miller-Morgan, DVM
Extension Veterinarian/Assistant Professor
Ornamental Fish Health Program
Sea Grant Extension
College of Veterinary Medicine
Oregon State University
Hatfield Marine Science Center
2030 SE Marine Science Drive
Newport, OR 97365
(541) 867-0265 (office)
(541) 270-4218 (cell)
tim.miller-morgan@oregonstate.edu
Web site: http://seagrant.orst.edu/extension/aquarium.html
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