GovWire

Contents

1. How to spot KHV
2. How KHV is spread
3. Preventing and controlling KHV
4. Further information on KHV
5. Legislation relating to KHV
6. Who to contact if you suspect KHV

Koi herpesvirus (KHV) is a highly contagious viral disease, causing serious disease outbreaks in all varieties of common carp (Cyrinus carpio) including mirror carp, leather carp, koi carp and ghost carp. It can cause mortality rates of up to 100%.

More information on susceptible and vector species can be found here: Lists of possible Susceptible and vector species (publishing.service.gov.uk)

KHV is present in Great Britain and is a Listed (also referred to as notifiable) disease which you are legally obligated to report immediately to the Fish Health Inspectorate (FHI), Cefas. KHV was first recorded in Israel in 1998 following large scale mortalities of farmed carp. It is known to occur in over 28 countries including Great Britain.

In Great BritainEngland and Wales outbreaks occur every summer in carp populations in recreational fisheries, and on occasion in ornamental koi carp. Disease outbreaks are subject to official controls to prevent further spread. These controls vary according to the water(s) or type of facilities affected and the potential risk of disease spread.

It does not affect humans.

How to spot KHV

The disease occurs in water temperatures between 16C and 29C. Stress events can trigger an outbreak. Fish often become lethargic and gather at water inlets or in the shallows.

Signs of the disease can include:

• Patches of dead (necrotic) tissue in the gills, often with secondary fungal or bacterial infection. Gills may also appear pale
• Sunken eyes
• Over or under production of mucus
• Rough, dry patches of skin
• Sloughing of mucus
• Appearance of bleeding on skin and base of fins
• Patchy pale colouration or reddening of the skin

How KHV is spread

KHV is spread through contact with infected fish or water. Virus is released via faeces, urine, gills and skin.

KHV can be spread through movements of infected fish, contaminated water, and contaminated equipment such as husbandry, angling and fish transport equipment.

Infected fish do not have to be sick or diseased to spread the virus.

Preventing and controlling KHV

There is no treatment for KHV.

Prevention is the best approach to disease control. You can protect your fish by being aware of the signs of KHV and other serious diseases and checking stock health regularly.

Implement good husbandry and biosecurity practises. Further information on biosecurity measures plans, guidance and templates can be found here: Biosecurity Measure Plans - Information and Templates - GOV.UK (www.gov.uk)

Do not buy fish of unknown origin. Follow the rules on importing, exporting or moving aquatic animals: Aquatic animal health and movements guides - GOV.UK (www.gov.uk)

You must report it to the FHI immediately if you notice or become aware of fish showing any of the signs of KHV. The FHI will investigate and apply disease control measures if required.

Further information on KHV

World Organisation for Animal Health (WOAH) Aquatic Manual chapter KHV.

Legislation relating to KHV

The Aquatic Animal Health (England and Wales) Regulations 2009

The listed diseases are in Regulation 1251/2008 as amended by the Animals, Aquatic Animal Health, Invasive Alien Species, Plant Propagating Material and Seeds (Amendment) (EU Exit) Regulations 2020, at Chapter 2, Annex 1A and Schedule 1 of The Aquatic Animal Health (England and Wales) Regulations 2009.

Who to contact if you suspect KHV

If you suspect or know of a listed disease of fish or shellfish in England and Wales, you must report it immediately to the Fish Health Inspectorate (FHI), Cefas. You must also tell the FHI immediately if you know or suspect that increased mortality has occurred.

Under the Aquatic Animal Health (England and Wales) Regulations 2009 it is a legal obligation to report suspicion of KHV in any farmed or wild fish to the FHI. It is an offence under the Regulations to fail to inform the FHI of suspicion of KHV.

• Email:?fhi@cefas.gov.uk
• Telephone: 01305 206700- Monday to Thursday - 9:00 am to 5:00 pm, Friday 9:00 am to 4:30 pm
• For emergencies out of hours telephone: 01305 206630