Spring Viremia of Carp,

United States

July 20, 2004

Summary:  Spring viremia of carp (SVC) was confirmed in ornamental koi carp in Pike County, Missouri on July 13, 2004.  One premises has been affected to date; bait and gamefish are raised at the facility in addition to ornamental koi.  The outbreak occurred after introduction of ornamental koi in June 2004.  SVC is a viral disease of fish; it primarily affects common carp.  It is a systemic, acute and highly contagious disease. 

In 1998, 115 facilities produced koi and 65 facilities produced ornamental goldfish in the US .   The combined sales value for koi and goldfish from these facilities is estimated to be $10.7 million.  Missouri had 2 facilities that produced koi and 1 facility that produced ornamental goldfish in 1998.

Missouri exported live carp worth $5,224 during 2003 and no live carp during January through April, 2004.  The US exported live carp worth $1.7 million in 2003 and $651,000 during the first four months of 2004. 

How extensive is the situation?

Spring viremia of carp (SVC) was confirmed in ornamental koi carp in Pike County, Missouri on July 13, 2004.  One premises has been affected to date; bait and gamefish are raised at the facility in addition to ornamental koi.  The outbreak occurred after introduction of ornamental koi in June 2004.  Mortality of approximately 70 percent in 500 susceptible animals occurred in the two weeks following shipment.

Diagnosis was confirmed at the National Veterinary Services Laboratory using virus isolation and polymerase chain reaction tests.

Tracebacks to determine the source and extent of infection are underway.  The affected facility will be depopulated, cleaned and disinfected.

Source:  OIE, USDA/APHIS/Veterinary Services Missouri Area Office

What is SVC and where does it occur?

SVC is a viral disease of fish; it primarily affects common carp.  It is a systemic, acute and highly contagious disease.  SVC is caused by Rhabdovirus carpio, which is a bullet shaped virion, typical for rhabdoviruses.  SVC typically occurs when water temperatures are less than 18°C and is most common in the spring.  At 20-22°C, infection occurs but clinical disease does not develop, as the fish is able mount an immune response at this temperature.  When clinical disease is present, mortality ranges from 30-90%, and is dependent upon fish age, water temperature, fish species and living conditions.  Clinical signs include congregation in slow moving water, decreased respiration and decreased response to stimuli.  Other, nonspecific signs such as skin darkening, swollen abdomen, exophthalmia, pale gills and protruding vent may also be present.  The gill is the most common portal of entry.  SVC is transmitted horizontally through the water and by blood sucking parasites such as the carp louse (Argulus foliaceus) and leech (Pisciola geometra).  Successful treatment of infected fish has not been demonstrated.  There is no approved vaccine for SVC in the US .  Control measures include iodophore disinfection of eggs and periodic chemical and physical disinfection of ponds and equipment.  Minimizing stress and overcrowding and sanitary disposal of dead fish are also recommended.  Raising fish at a water temperature of 19-20° C has been suggested. 

SVC has previously been reported in Europe, the Middle East and Asia.  More recently, it has been reported in North and South America.  In the US , SVC outbreaks occurred in North Carolina in 2002 and Washington in June 2004.  The virus has also been reported in feral common carp populations in Wisconsin and Illinois.  SCV is an OIE notifiable disease.

Sources:  APHIS VS Tech Notes, CEI Impact Worksheets, Federal Register/Vol. 69, No. 95, OIE

What species are susceptible to the SVC virus and are they present in Missouri?

Most of the fish species that are susceptible to the SVC virus belong to the Family Cyprinidae.  While the common carp (Cyprinus carpio), including the Koi variety, are the primary Cyprinidae species affected, other Cyprinidae species and a few species not in the Family Cyprinidae are also susceptible to the SVC virus. 

In addition to the common carp, species that have been found to be susceptible to the SVC virus under natural conditions include the grass carp (Ctenopharyngodon idellus), silver carp (Hypophthalmichthys molotrix), bighead carp (Aristichthys nobilis), crucian carp (Carassius carassius), goldfish (Carassius auratus), tench (Tinca tinca), and sheatfish (Silurus glanis).  Under experimental conditions, golden shiners (Notemigonus crysoleucas), roach (Rutilis rutilis), pike (Esox lucius), guppy (Lebistes reticulates), pumpkinseed (Lepomis gibbosus), and zebra danios (Brachynadio rerio) were also found to be susceptible to the SVC virus.  Feral populations of common, grass, bighead, and silver carp are found in Missouri.

In the US , there are additional species in the Family Cyprinidae, the principal SVC virus hosts, and their susceptibility to the SVC virus is not presently known.

Sources: Spring Viremia of Carp, APHIS Technical Note, April 2003

What is the size of the affected cyprinid industry in the US and in Missouri?

The most recent data on fish sales by species and state are available on the National Agricultural Statistical Services (NASS) 1998 Census of Aquaculture.  These data show that there were a total of 115 facilities producing koi and 65 facilities producing ornamental goldfish in the US in 1998 (Table 1).  The combined sales value for koi and goldfish from these facilities is estimated to be $10.7 million.  Missouri had 2 facilities that produced koi and 1 facility that produced ornamental goldfish in 1998.  These categories are not mutually exclusive, i.e., the same facility may produce both koi and ornamental goldfish.  Due to producer confidentiality requirements, the sales value of koi and goldfish production for Missouri is not available. 

In 1998 there were 34 facilities in the US that produced feeder goldfish (bait) and 39 facilities that produced carp as food fish.  The value of production for these categories of cyprinids was $9.3 million and $1.3 million, respectively.  Missouri had 3 facilities that produced feeder goldfish and no facilities that produced food carp. 

Table 1.  Number of facilities and value of sales for affected fish in the US and Missouri, 1998.

                                - = withheld to avoid disclosing data for individual farms

Source:  USDA, NASS, 1998 Census of Aquaculture

What is the US ’s place in the international market for affected fish?

The US produced 10,869 metric tons of carps, barbels, and other cyprinids in 2001, accounting for less than 0.1% of world production.

Source: United Nations FAO

What are the US exports of affected fish?

Missouri exported live carp worth $5,224 during 2003 and no live carp during January through April 2004 (Table 2).  (Note:  This information reflects the state of export, which may be different than the state in which production occurred.)  The US exported live carp worth $1.7 million in 2003 and $651,000 during the first four months of 2004.  These fish were exported almost exclusively to Canada , with only minor sales values to Mexico and Trinidad and Tobago in 2003.

Table 2.  US exports of live carp, 2003 and January-April 2004.

	2003 ($ million)		Jan-Apr 2004 ($ million)
Product	US	Missouri	US	Missouri
Live carp	1.697	0.005	0.651	-

Source: State Export Data, World Trade Atlas

CEI’s plans for follow up:

CEI will continue to monitor the situation but has no plans at this time to issue additional reports. 

If you seek more information or wish to comment on this worksheet, please contact Judy Akkina at 970-494-7324 or Kathy Orloski at 970-494-7221.