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Viral diseases

Spring Viremia of Carp

Spring Viremia of Carp (SVC) is caused by the virus rhabdovirus. The disease has been reported in almost all carp species, including gold fish. It is contagious and mostly fatal when effecting fish. The virus is shed in the feces, urine and gill secretions of infected fish into the water where it infects other fish. The virus may be introduced into the pond by new additions of koi, contaminated equipment, clothing and also frogs and birds that migrate between bodies of water. The mortality rate associated with SVC can reach 90 percent depending of the age of the fish and water temperature. As the name implies, outbreaks of SVC are common in spring and autumn.

The rhabdovirus that causes SVC enters the fish through the gills. Other ways of contracting the disease is through blood sucking parasites like leeches and fish lice. Experimental transmission has been successful with introduction of infected fish, immersion into effected water and through intraperitonal injection. It is said that application of the virus to lesions on the skin did not result into transmission of the virus. It is also suggested that the virus can be passed on from female parent, to egg to juvenile.

Symptoms associated with SVC
  1. Darkening of body colour
  2. Pop-eye (Exophthalmia)
  3. Dropsy (ascites), distended abdomen
  4. Fish will breathe slowly and congregate in slow moving water
  5. Tilting to one side, lying on pond bottom.
  6. Bloody discharge from vent, gills and eyes.
  7. Simultaneous infection with bacteria may confuse the diagnoses.
  8. Internally, build up of fluid and pinpoint haemorrhages in many organs may be found.

Prevention of SVC
  1. Maintaining water temperature above 20 degrees Celsius may prevent an outbreak of SVC.
  2. Sound bio security must be establish and maintain.

Treatment of SVC
  1. There is no specific treatment of SVC.
  2. Survivors will be “Carriers”’ so these must be isolated for life.
  3. If SVC is confirmed in a pond, depopulation is recommended.

Last Updated on Friday, 14 November 2008 08:40