June 28, 2006

Koi Herpesvirus (khv) Disease strikes 3 fishfarms in the UK

Outbreaks of Koi herpesvirus (KHV) disease have hit three fisheries in the South and East of England, the Environment Agency and the Centre for Environment, Fisheries and Aquaculture Science (Cefas) announced.

These are the first KHV mortalities recorded this year in fisheries and the most serious cases in terms of losses. The disease can wipe out up to 95 percent of stocks and there is no known treatment.

To prevent further spread of the disease, the Environment Agency is banning live fish movements off the affected sites. It is working with Cefas to find the source of the outbreak and identify any further sites that may be infected.

KHV is not subject to specific control measures under EU legislation. However, it is on the list of non-exotic diseases that is subject to control in the proposed Council Directive on animal health requirements for aquaculture.

KHV is a contagious disease of common carp, symptoms include lethargy, excess mucus and the appearance of rough pale patches of the skin. The virus has the ability to remain latent in the host for long periods of time, becoming active only at temperatures of between 15 deg C and 28 deg C.

There have been a number of isolated incidences of the disease in the UK since 2000 but this latest outbreak appears to be the more serious. KHV has occurred in several other countries in Europe and other parts of the world.

The Department of Farms and Rural Affairs (Defra) is funding a number of projects on KHV including programmes for improving diagnostic tests and non-lethal screening tests. It also funded an international workshop on KHV in 2004 to bring together world experts and raise the profile of the disease.