Bacterial kidney disease (BKD)
How to spot Bacterial kidney disease (BKD), what to do if you suspect it and measures to prevent its spread.
Applies to England and Wales
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Contents
- How to spot BKD
- How BKD is spread
- Preventing and controlling BKD
- Legislation relating to BKD
- Who to contact if you suspect BKD
Bacterial kidney disease (BKD) is a chronic bacterial disease in salmonid fish. Outbreaks have resulted in economic losses in business across England and Wales.
More information on susceptible and vector species listed in GB can be found here: Lists of possible Susceptible and vector species (publishing.service.gov.uk)
BKD is a ‘listed’ (also referred to as ‘notifiable’) disease which you are legally obligated to report immediately to the Fish Health Inspectorate (FHI), Cefas.
In the UK BKD has been found in both fresh and seawater locations in Scotland, England, and Wales. Northern Ireland is free from BKD.
It does not affect humans.
How to spot BKD
Fish may become lethargic and appear darker in colours and have bruising around the vent. It may take several months before disease signs appear. Outbreaks can occur year-round but generally associated with rising water temperatures in spring.
Signs of the disease can include:
- Pale gills
- Dark colouration
- Swollen abdomen
- Bulging eyes
- Pinprick like bleeding at vent
- Small skin ulcers/blisters
- Enlarged kidneys, lesions or nodules may be observed on kidneys or other internal organs
- Opaque membrane covering internal organs
How BKD is spread
BKD can be spread through movements of infected fish, contaminated water, and contaminated equipment such as husbandry, angling and fish transport equipment and boats. Infected fish do not have to be sick or diseased to spread the virus.
Movements of infected fish or their eggs is the main route by which BKD is spread.
Preventing and controlling BKD
There is no effective treatment for BKD.
Prevention is the best approach to disease control. You can protect your fish by being aware of the signs of clinical BKD and other serious diseases and checking stock health regularly.
Implement good husbandry and biosecurity practices. 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 moving aquatic animals: Aquatic animal health and movements guides - GOV.UK (www.gov.uk)
Since 2011, GB implemented a domestic programme for the control of clinical BKD disease, and statutory controls are only applied when clinical disease is evident. Clinical BKD is confirmed by a combination of morbidity or mortality in a population, the presence of external clinical signs or internal gross pathology and evidence for the presence of the bacterial pathogen Renibacterium salmoninarum through one or more laboratory tests.
You must report it to the FHI immediately if you notice or become aware of fish showing any of the signs of BKD. The FHI will investigate and apply disease control measures if required.
Legislation relating to BKD
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 BKD
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 BKD 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 BKD.
- 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
Fish Health Inspectorate
Centre for Environment, Fisheries and Aquaculture Science (Cefas)
Barrack Road, The Nothe
Weymouth
Dorset
DT4 8UB