How to spot chronic wasting disease (CWD), what to do if you suspect it and measures to prevent its spread.
Chronic Wasting Disease (CWD) is a highly contagious and fatal disease that affects most wild and farmed deer species including:
- mule deer
- white-tailed deer
- red deer
- roe deer
- North American moose (known as elk in Europe)
- white tailed deer (indigenous to North America)
- fallow deer
- Chinese water deer
Humans aren’t affected, nor are animal products or meat such as venison.
There have been no outbreaks in the UK but in 2016 it was diagnosed in wild deer in Norway, the first cases of CWD in Europe. The disease has also killed wild and farmed deer in North America.
The 2016 qualitative risk assessment on the risk of a cervid transmissible spongiform encephalopathy (TSE) being introduced from Norway into Great Britain concludes that the public health risk of CWD isn’t known. Current assessments suggest the risk is very low.
Chronic wasting disease is a notifiable animal disease. If you suspect it you must report it immediately by calling the Defra Rural Services Helpline on 03000 200 301. In Wales, contact 0300 303 8268. In Scotland, contact your local Field Services Office. Failure to do so is an offence.
How to spot CWD
In most cases of CWD there is a general change in behaviour and loss of weight over time, particularly in the later stages of the disease. Deer may show a number of different clinical signs over several weeks.
The disease is progressive and fatal.
Deer may take 18 to 24 months to show clinical signs after becoming infected and will become more infectious to other deer as the incubation progresses.
Changes in behaviour
You may see in infected deer:
- separation from other animals in the herd
- depression or blank facial expression
- lowering of the head
- difficulty swallowing
- increased thirst and urination
- less interest in hay but continue to eat grain
- teeth grinding
- nervousness and excitement
Changes in posture and movement
Infected deer may:
- stumble and have poor coordination
- be listless and dull
- walk in set and repeat patterns
- have tremors
- have paralysis
You can help prevent the disease by practising strict biosecurity on your premises.
You must not feed:
- animal protein to ruminants including deer
- processed animal protein to farmed deer
though there are exceptions.
CWD is a TSE disease so you must follow TSE regulations and feed controls.
Contaminated clothing and equipment
Countryside users bringing in contaminated clothing and equipment could transmit CWD.
Hunters or stalkers who have hunted in parts of North America where CWD is present might transmit CWD in the UK.
CWD is highly infectious and very resistant to weather conditions and traditional disinfectants so it can remain in the environment for a long time. CWD can stick to soil particles for up to 10 years.
The only way to rapidly inactivate CWD’s infectious agent is to soak clothes or equipment in a solution of bleach that has 20,000 parts per million of active chlorine, or 2 molar sodium hydroxide solution, for one hour.
This treatment will damage or destroy most clothing, footwear and hunting equipment.
Countryside visitors to the UK
If you’re a hunter or stalker visiting the UK from an area where CWD is present you should:
- not bring clothing or equipment that you’ve used for hunting or stalking with you because it may be contaminated
- clean any clothing or equipment of soil, blood and faeces so it’s not contaminated
- not bring any trophies or body parts into the UK
Hosts and sporting agents
Your guests from the USA or Canada, or those who have visited CWD-infected areas, may not understand the transmission risks.
You should check all of their kit for cleanliness - it probably won’t get inspected at border control.
Deer urine lures
Hunters should not use or trade deer urine lures because they may contain infected urine which can transmit CWD. You can use synthetic lures.
You must not:
- import unprocessed deer urine into the UK
- export unprocessed deer urine to the EU, Norway,Finland or to third countries via the EU
If you report suspicion of CWD, APHA vets will investigate.
They may decide to keep your animal under observation to decide whether or not it’s a TSE suspect. The vet will restrict the movement of the animal from the farm and will visit the animal during the observation period.
If the vet decides that your animal is a TSE suspect, the vet will restrict the movement of animal and issue a notice of intention to kill. After death, brain samples will be sent for post-mortem laboratory examination.
If tests confirm a TSE infection
If these tests confirm TSE, there will be further investigations of your herd and additional disease control measures may be put in place.
You will be paid compensation for a deer that is killed because it’s suspected of being affected with a TSE. The amount paid is based on the market value of the animal at the time it was killed.