Carp Edema virus (CEV)

Disease Identification Sheet

There are only two noticeable signs of carp Edema virus.

The first sign is the lethargy of the fish. They gather at the margins and in the upper layers of the water, reacting little to disturbance.

The second sign of the Edema virus is extreme gill damage (image right), leading to clubbing of the gill filament, cell proliferation (hyperplasia) along with cell death.

The scientific bit...

Gills-of-CEV-infected-Koi-Swelling-of-th

Carp Edema was discovered first in young carp of the coloured variety in japan in the 1970’s. known generally as Carp Edema Virus (CEV) it is also known by the name Koi sleepy disease (KSD). The virus was then further discovered in most European countries as well as in the Russian territory. Further reports show that the disease/virus is not just affecting coloured carp; it has spread into the common carp population. New cases in Austria and the Czech Republic have shown the disease effecting mature coloured carp and not just affecting juveniles. Which had been the case in many of the early outbreaks. CEV/KSD is a relatively new disease that has merged out of the east.

Characterised by its lethargic effects, enophthalmia (sunken eyes), generalised oedematous (swelling) condition in combination with gill necrosis (death), leading into hypoxia (loss of oxygen to the body or region of the body). The disease has a massive mortality rate of 80%-100% in young fish of the juvenile class.

Viruses can have a trigger of temperature this can be in many ranges depending on the virus where becoming more active they will cause disease. A lot of the diseases have temperature triggers, this happens as the weather and water warm through the spring and summer months. The cases in japan confirm this with outbreaks being reported with temperatures ranging from 15 - 23 degrees centigrade. However there have been reports that have seen the detection of CEV in water with temperatures as low as 3 degrees centigrade. This could have wide reaching implications for fisheries world wide. Changes of practice and good management could help to prevent the spread of the disease.