Spring Viremia of

Carp

Spring viremia of carp (SVC) is a contagious and

potentially fatal viral disease affecting fish. As its

name implies, SVC may be seen in carp in the spring

time. However, SVC may also be seen in other 

seasons (especially in the fall) and in other fish

species including goldfish and the European wells

catfish. Until recently, SVC had only been reported in

Europe and the Middle East. The first cases of SVC

reported in the United States were in Spring 2002 in

cultivated ornamental common carp (koi) and wild

common carp. The number of North American fish

species susceptible to SVC is not yet known.

Signs of SVC in Fish

The first signs of SVC disease in fish may be a

change in behavior. The diseased fish may breathe

and move more slowly, form groups in slow–flowing

water near the pond bank, and lie on their side at the

pond bottom. On the outside of a fish with SVC, the

skin and gills may appear dark red, the eyes may

bulge outward, the belly may be swollen, and bloody

mucus may hang from the vent. On the inside of a

fish with SVC, a lot of fluid may be in the belly cavity

and internal organs, blood in the swim bladder, and

reddening and swelling of the gut. However, not all

fish showing these signs necessarily have SVC, as

these same signs may also be seen in many other

diseases. Those fish that don't die from SVC may

recover and appear healthy, but these fish actually

may remain infected with the SVC virus and continue

to shed and spread the virus to other fish. Because

the SVC virus may remain hidden in infected fish, the

disease is difficult to eliminate from a site. Diagnosis

of the SVC virus in fish can be confirmed through

virus isolation and other sophisticated diagnostic

tests done by an approved laboratory.

SVC Spread and Control

The spread of SVC may occur through 

contact with water contaminated with the infected

fish's feces, urine, or mucus. The virus may be

spread through contaminated equipment, fish 

parasites, predatory birds, and on the outside of an

infected fish's eggs. Once SVC is established at a

site, it may be difficult to eradicate because of

virus–infected carrier fish. It may be necessary to

destroy all aquatic life in a pond to eliminate the 

disease from the site.

Although complete eradication is difficult, SVC

can likely be controlled and contained within

high–risk zones through surveillance and better 

management practices, including strict biosecurity

procedures. People may transmit the virus with them

from place to place on their clothing, footwear, 

equipment, etc., but the virus does not cause disease

in humans. There has never been a single report of

humans being infected with the SVC virus either from

contact or from eating an infected fish.

SVC Prevention Information for

Hobbyists

Hobbyists who actively transport and show their

fish in organized competitive koi shows should only

show their fish in English–style shows. In

English–style shows, each participant's koi are kept

in separate show tanks. From a disease 

transmission viewpoint, most aquatic animal health

professionals recommend the English–style shows.

Good biosecurity measures (e.g., avoidance or 

disinfection of any potentially infected, shared 

equipment) while at a show is highly recommended

and will also protect fish from infection by the highly

contagious koi herpes virus and other communicable

diseases.

SVC Prevention Information for Anglers

Anglers should not transfer fish or fish parts from

one body of water to another, as this practice not

only risks spreading the SVC virus and other 

disease–causing agents, but also risks spreading

non–native fish and other aquatic nuisance species.

Anglers should use only disease–free bait purchased

from commercial producers. If a large number of

dead or dying fish is observed in a natural body of

water, anglers should contact the game and fish

department of their State natural resources agency.

SVC Prevention Information for

Producers

There are several recommendations for 

preventing SVC from becoming established on 

commercial farms. Using a source of water that is

free from disease such as a spring or well is 

necessary, especially in an area where the disease is

known to exist. Other on–farm measures include 

disinfection of eggs by iodophore treatment, regular

physical and chemical disinfection of ponds, 

disinfection of equipment, and proper disposal of

dead fish. Also, new fish being brought onto farms

should be purchased from a source known to be free 

Factsheet

Veterinary Services April 2003

APHIS
of SVC. Bringing new fish, especially cyprinids 

including carp, koi, and goldfish, onto a fish farm

should be undertaken only with great caution.

Currently, no vaccine for SVC is commercially

available in the United States. SVC is an Office

International des Epizooties (OIE) List B, reportable

disease, and the United States Department of

Agriculture is required to report any outbreaks to the

OIE. If a producer suspects SVC, he or she should

contact, as soon as possible, the State veterinarian or

the local Animal and Plant Health Inspection Service’s

Veterinary Services office.

Additional Information

Current information on aquatic animal diseases

and suspected outbreaks is available on the Internet

at http://www.aphis.usda.gov/vs/aqua/aquaphis.html.

For more information contact:

USDA, APHIS, VS

Emergency Programs Staff

4700 River Road

Riverdale, MD 20737

Phone: (301) 734–8073

International Association of Fish and Wildlife 

Agencies on the Internet at http://www.iafwa.org 

to obtain a listing of all State and provincial 

contacts, or by phone at (202) 624–7890.

National Association of State Aquaculture 

Coordinators on the Internet at 

http://www.ncagr.com/aquacult/NASAC.html to 

obtain a contact for all State aquaculture 

regulatory agencies, or by phone at 

(916) 653–9583.

NOAA Fisheries on the Internet at 

http://www.nmfs.noaa.gov, or by phone at 

(301) 713–2379.

North Carolina Wildlife Resources Commission on

http://www.ncwildlife.org, or by phone at 

(919) 733–3633.

Unversity of Florida

Institute of Food and Agricultural Sciences on the 

Internet at http://edis.ifas.ufl.edu or by phone at 

(352) 392–9617

U.S. Fish and Wildlife Service Fish health Centers

at http://fisheries.fws.gov/FHC/FHCcu.htm or by

phone at (703) 358–1856.

The U.S. Department of Agriculture (USDA) prohibits discrimination

in all its programs and activities on the basis of race, color, national

origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to

all programs.) Persons with disabilities who require alternative

means for communication of program information (Braille, large

print, audiotape, etc.) should contact USDA’s TARGET Center at

(202) 720–2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of

Civil Rights, Room 326–W, Whitten Building, 1400 Independence

Avenue, SW, Washington, DC 20250–9410 or call (202) 720–5964

(voice and TDD). USDA is an equal opportunity provider and

employer.

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture