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Spring Viremia of Carp Virus

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Spring viremia of carp (SVC) is a viral disease of fish that primarily affects cyprinid

species such as carp. It is caused by the virus Rhabdovirus carpio. Water

temperature affects the development of the disease. Outbreaks are most common in

the spring as temperatures rise. SVC may present as an acute and highly contagious

disease that can cause substantial economic losses. Mortality rates in infected fish

range from 30 to 90 percent.
While not considered widespread in the United States, SVC is an internationally

notifiable disease. APHIS follows World Organisation for Animal Health guidance on

reporting all confirmed cases of this disease.

What To Look For

Fish can carry the SVC virus with or without symptoms. When they do show

symptoms, you may see one or more of the following:

Abdominal distension

Exophthalmia (bulging eyeballs)

Inflammation of the vent (often with trailing mucoid fecal casts)

Petechial hemorrhages (look like red or purple spots) of the skin, gills, and eyes

Darkened body with pale gills

Gathering at water inlet or sides of pond

Swimming and breathing slowly

Reacting slowly to stimuli

Loss of equilibrium in later stages

Common carp are the most susceptible to SVC. Young fish (up to a year old) are

most likely to be affected, but the illness also occurs in older fish.

How To Prevent This Disease

The SVC virus is shed mainly in the feces and urine, as well as the gills and skin

mucus of infected fish. It usually spreads between fish either by direct contact or

through the water.

Biosecurity Helps Prevent SVC From Spreading

If you're a producer, here's what you can do:

Use spring or well water.

Purchase fish from sources that test negative for SVC virus.

Treat fish eggs with iodophore (disinfectant).
Regularly disinfect ponds and farm equipment.

Dispose of dead fish safely, per State regulations for livestock disposal.

Reduce fish density in winter and early spring.

Increase water temperature to at least 66–68 °F.

If you're a hobbyist who shows fish, only participate in events where each

participant’s fish are kept in separate tanks.

If you're an angler, avoid transferring fish or fish parts between bodies of water.

Trade Restrictions Protect U.S. Fish Health

APHIS restricts the import of live fish, fertilized eggs, and gametes from SVCsusceptible species. These include common carp, koi, grass carp, silver carp,

bighead carp, Crucian carp, goldfish, tench, and sheatfish. Learn more about our

trade restrictions.

How It Is Treated

There is no treatment for SVC. Once the SVC virus is established in a pond, it can be

difficult to eradicate unless all aquatic life at the site is destroyed.

Testing

If SVC is suspected or detected at a laboratory, the detection should be confirmed at

the National Veterinary Services Laboratories in Ames, IA.

Report Signs of Animal Disease

Producers or owners who suspect an animal disease should contact their

veterinarian to evaluate the animal or herd. Find an accredited veterinarian.

Animal health professionals (veterinarians; diagnostic laboratories; public health,

zoo, or wildlife personnel; and others) report diagnosed or suspected cases of

nationally listed reportable animal diseases to APHIS District Offices and to the State

animal health official as applicable under State reporting regulations.