Bovine spongiform encephalopathy (BSE): how to spot and report the disease

Q&A – Classical BSE case in Ayrshire in May 2024

What has happened today?

A single case of classical Bovine Spongiform Encephalopathy (BSE) has been confirmed on a farm in Ayrshire . The animal died on farm and was tested as part of our surveillance programme. There is no risk to human health or food safety. The animal was a breeding animal not intended to enter the food chain. British beef is safe and can be traded as before.

Classical BSE is not contagious, so it does not spread directly between animals. It occurs mainly through the consumption of feed contaminated with the BSE agent.  The strict feed controls introduced in 1988 and strengthened in 1996 has meant that the incidence of BSE cases in the UK has been greatly reduced, with only 5 cases of classical BSE confirmed since 2014 (including this one). All of these detections  have been in animals which were not destined for the human food chain and therefore posed no risk to the public. Occasional cases are to be expected and this is in line with projections for the tail end of the 1992 epidemic.

The last case of classical BSE in the UK was detected by routine surveillance in England in September 2021.

Date	2014	2015	2016	2017	2018	2019	2020	2021	2022	2023	2024
BSE cases	1	1	0	0	1	0	0	1	0	0	1

 What happened to the cow that tested positive for BSE?

As the cow was fallen stock it was automatically barred from entering the  food chain.. The cow died on farm after displaying clinical signs consistent with BSE and the carcase was taken to a disposal site. As part of the surveillance programme for BSE, a brain sample was taken prior to the carcase being disposed of by rendering.

Whole farm movement restrictions were applied on first suspicion of the disease, while the cohorts – animals that shared feed with the affected animal during its first year of life - and offspring born in the last two years were traced. Further restrictions were put on three farms.

The whole farm restriction were then removed, with restrictions applied in a targeted manner to the cohorts and offspring on a precautionary basis. Their passports have been removed so that they cannot enter the food chain.

Are you stopping all animal movements from Scotland to other areas of GB? If not, why?

We are not stopping animal movements as there is no scientific or legal basis for doing so. BSE is not contagious, so it does not spread from animal to animal or between holdings. There is no risk to animal or human health posed by this isolated case given the strict controls on beef entering the food chain. Despite BSE not being contagious, the cohorts and offspring born in the last 2 years to the animal have been identified and will be humanely culled on a precautionary basis. These animals will undergo testing for BSE.

This case was identified as a result of our strict control measures. It did not enter the human food chain and Food Standards Scotland (FSS) have confirmed there is no risk to human health.

When will we know the cause of the incident?

The Animal and Plant Health Agency (APHA) has begun a full veterinary enquiry and epidemiological investigation to determine the cause of this case.  An epidemiological report will be published in due course.

What is the history of this farm?

For reasons of confidentiality, we are unable to disclose information about this farm.

The CVO SCOTLAND has confirmed a single case of classical BSE. APHA will begin a thorough investigation of the herd, the premises and potential sources for this case and will produce a full epidemiological report in due course.

Can you tell us where the farm is?

The farm is located in Ayrshire. For reasons of confidentiality, we are unable to disclose further information about this farm.

What steps can farmers take to stop BSE within their herds?

BSE is a notifiable disease and farmers should notify APHA of any suspicion of the disease within their herd and should follow the rules on livestock feed as set out in the Government’s BSE guidance.

Due to the potential risk of BSE from feed predating the reinforced feed ban of 1 August 1996, we strongly recommend feed silos that pre-date 1 August 1996 be decommissioned and replaced. If this is not possible, then we strongly urge you to arrange for cleaning, in line with Government guidance, as soon as is practicably possible to ensure that any remnants of old feed are removed. More detail is set out on the Government’s website here.

Should people stop eating British beef and milk?

No. The cow was not destined for the human food chain and the Food Standards Scotland (FSS) have confirmed there is no risk to human health as a result of this isolated case.  British beef is safe.

Have there been incidents in any other countries?

Number of cases worldwide.

What is the global status of BSE?

The World Organization for Animal Health (WOAH) has established official recognition of BSE risk status in WOAH members. WOAH officially recognises two categories of BSE risk status: negligible risk and controlled risk. There is also an undetermined risk status for countries that have not applied for official recognition of their BSE risk status.

Please see the map for countries with BSE controlled and negligible risk status.

Scotland, and England and Wales, have BSE controlled risk status as two separate WOAH zones. Northern Ireland has negligible risk status. British beef is safe and can be traded as before.

Will this affect our trading status? Will other countries stop importing British beef?

British beef is safe and can continue to be exported to trading partners.

UK regulatory controls are effective, and we have strict controls in place to protect the food and feed chain and safeguard public health. Beef can be safely traded under international rules from countries with WOAH official BSE controlled or negligible BSE risk status.  

This single classical BSE case does not immediately affect our official BSE risk status. Defra, working for all UK Administrations, has 90 days to provide to WOAH an epidemiological report with the outcome of the investigations on this case, demonstrating that any identified source of infection has been controlled and the risk of BSE agents being recycled within the bovine population has continued to be negligible.

Do we currently have BSE Controlled risk status?

Scotland, and England and Wales, as two separate WOAH zones, have official BSE controlled risk status. Northern Ireland has official BSE negligible risk status.

This single classical BSE case does not immediately affect our official BSE risk status. Defra, on behalf of all UK Administrations, has 90 days to provide to WOAH an epidemiological report with the outcome of the investigations on this case, demonstrating that any identified source of infection has been controlled and the risk of BSE agents being recycled within the bovine population has continued to be negligible.

Does the confirmation of a new case of classical BSE mean that we lose official BSE controlled status? 

This single classical BSE case does not immediately affect our official BSE risk status. Defra, on behalf of all the UK Administrations, has 90 days to provide to WOAH an epidemiological report with the outcome of the investigations on this case, demonstrating that any identified source of infection has been controlled and the risk of BSE agents being recycled within the bovine population has continued to be negligible.

Does this classical BSE case delay our ability to apply for ‘negligible risk’ status this summer?

This case will not affect our ability to apply to WOAH for negligible risk status this summer if we can demonstrate to WOAH that any identified source of infection has been controlled and the risk of BSE agents being recycled within the bovine population has continued to be negligible.

What is Bovine Spongiform Encephalopathy?

Bovine spongiform encephalopathy (BSE), sometimes referred to as "mad cow disease", is a chronic degenerative disease affecting the central nervous system of cattle. The disease belongs to the group of transmissible spongiform encephalopathies, which also includes classical and atypical scrapie in sheep and goats and chronic wasting disease (CWD) in deer.

What are signs of BSE?

Affected cattle do not usually show signs of BSE until they are at least 4 or 5 years old. Cattle with BSE may slowly develop some of the following signs over a period of weeks or months:

• change in behaviour
• apprehension or nervousness (flighty)
• repeated, exaggerated reactions to touch or sound
• weakness or high stepping of the legs, particularly the hind legs
• reluctance to cross concrete or drains, turn corners or enter yards or go through doorways
• aggression towards humans or towards other cattle
• manic kicking during milking or reluctance to allow milking
• head held low
• difficulty in rising, progressing to recumbency
• tremors under the skin
• loss of body condition, weight or milk yield
• excessive nose licking

What is the difference between classical and atypical BSE?

Classical BSE was first diagnosed in the United Kingdom in 1986. Epidemiological studies suggest that the source of this disease is contaminated cattle feed. Scientific research has not identified any other definite vector of transmission.

Atypical BSE has different characteristics to classical BSE. Evidence suggests that atypical BSE types are spontaneous and there is no clear cause. It must therefore be expected that single cases of atypical BSE in cattle can occur at any time.

How is Classical BSE spread?

The disease is not contagious, so it does not spread from animal to animal or between holdings. Scientific opinion is that classical BSE can be transmitted by contaminated feed.

As a result of this scientific opinion, a ban on feeding any animal protein to ruminants was put in place in the UK in 1996.  Under this and later ‘feed bans’ it is illegal to feed (with certain exceptions e.g. milk and eggs) animal protein to ruminants and it is illegal to feed (with certain exceptions) processed animal protein to farmed animals. 

When was the last case of BSE in the UK?

The last case of atypical BSE was in Cornwall in March 2023, with a prior case in 2015.

The last case of classical BSE in the UK was in Somerset in September 2021. Before that, one case was confirmed in the UK in 2014, 1 case in 2015, 0 cases in 2016, 0 cases in 2017, 1 case in 2018, 0 cases in 2019 and 0 cases in 2020. There were no classical BSE cases in 2022. All of these animals were fallen stock, so they were not intended for human consumption.

The last case of classical BSE in Scotland was in October 2018 in Aberdeenshire.

What controls are in place to prevent BSE?

We remain vigilant to the threat posed by BSE and the following key controls, that protect public and animal health, will remain in force:

• the ban on feeding animal protein to farmed animals, which prevents the spread of BSE to animals through feed
• removing specified risk material (SRM) – the riskiest parts of animals – at slaughter to protects consumers from risk from food
• surveillance to monitor the level of BSE over time and thereby check on the continued effectiveness of BSE controls
• all fallen stock bovines aged over 48 months (animals that die or are killed other than for human consumption) are routinely tested for BSE under our comprehensive surveillance system

Under our robust surveillance programme, the UK undertook 109,020 BSE tests in 2021 and 103,515 tests in 2022.

Will other animals related to this cow need to be culled? When and how will this happen?

The cohorts, and offspring (aged up to 24 months) of the diseased cow will be humanely culled and the carcases destroyed. Cohorts are animals which are born or reared with the affected animal, born up to 12 months before or after it, which shared feed with it during the first 12 months of life.  This is a precautionary measure required by UK legislation.

All of these animals will be humanely killed and tested for BSE. The owners of the culled animals will receive compensation.

Why do you kill the cohorts and offspring of BSE cases if they exhibit no symptoms of the disease?

Cohorts are animals which were born up to 12 months before or after the confirmed case and were reared and shared feed with it. They are removed from the food chain, humanely killed and destroyed and are tested for BSE. This is a purely precautionary measure taken IN CASE they were exposed to contaminated feed at the same time as this case.

The offspring of the diseased cow aged under 24 months are also culled as a precautionary measure required by UK legislation.

To date, there is no test for BSE for live animals. BSE is confirmed by taking samples from the brain of an animal and testing to see if there are abnormal prion proteins present. It is therefore required to cull the animals before we can test them.

How are farmers compensated for any cattle culled?

Compensation is the average price paid in Great Britain for that age and category of animal for a pedigree animal, in the previous 6 months before the date of its valuation; and for any other bovine animal, in the previous month before the date of its valuation.

We pay the average of all recorded prices received for each category over a given period. This represents a considered attempt to strike a balance between protecting the interested of cattle farmers and those of the taxpayers.

What support is offered to affected farmers?

We sympathise with the farmer affected. No-one wants to have to cull animals if it can be avoided, but it is vital that we maintain our controls to eradicate BSE. Farmers will receive compensation for any animal culled. Our dairy and beef industries are part of the agri-food sector which contributes billions of pounds to the UK economy each year. These controls are key to maintain animal and public health, the reputation of the industry and our export markets.

RSABI provides support to people involved in the Scottish agricultural industry, including farmers, crofters and farm workers, and their dependents. More information can be found on their website.

What controls are in place to prevent affected cattle entering the food chain?

There is a robust inspection regime at abattoirs to ensure that only healthy animals enter the food chain. Animals under any BSE restrictions (for example awaiting culling) would not be able to travel to abattoirs and enter the food chain. Ante-mortem and post-mortem inspections at abattoirs are designed to ensure that only healthy animals enter the food chain.

The parts of an animal most likely to contain BSE if the animal is infected are removed when an animal is slaughtered, and they do not go into our food. This is called the Specified Risk Material (SRM) Control and is the key control to protect human health. This means that in the extremely unlikely event of an animal with BSE being slaughtered for human consumption, all the most infective parts of the animal would have been removed and destroyed at slaughter before it entered the food chain.

An additional control was also introduced banning the process of recovering meat mechanically from the bones of cattle.

These measures are in addition to the rules we have in place for the safe disposal of fallen stock and controls on animal feed, and our robust surveillance system. 

If there were animals slaughtered in the previous days prior to the case confirmation, did FSS instigate a recall/ withdrawal for that meat?

All animals at risk have been identified by APHA and placed under restriction, with passports seized. There is no reason to believe that other animals which have entered the food chain in the lead up to this, pose any risk to the food chain, so no recall/ withdrawal would be necessary.

What is specified risk material?

Specified risk material are parts of an animal most likely to contain BSE if the animal is infected, such as the spinal cord, brain and skull from carcasses.

How is BSE transferred to humans? 

The infectious agent, a prion, which causes classical and atypical BSE in cattle can be transmitted to humans through consumption of contaminated meat. There is no risk of this happening because of the controls on SRM and fallen stock

What danger BSE can pose to humans?

The infectious agent, a prion, which causes BSE in cattle can cause variant Creutzfeldt-Jakob disease (vCJD) in humans (first identified in 1996). vCJD is not contagious, it does not spread.

Which animals are tested for BSE?

Bovine animals are tested for BSE if they are born in the UK or in an EU country other than Romania or Bulgaria and:

• the animal is aged over 48 months and showed signs of sickness when examined by a veterinarian before death
• the animal is aged over 48 months and has been sent for emergency slaughter (for example, casualty animals which do not appear to be unwell, but have broken a leg or suffered some other injury)
• the animal is aged over 48 months and is fallen stock, that is, their death was not due to being slaughtered for human consumption

In addition, our surveillance programme requires:

• BSE testing of bovine animals slaughtered for human consumption at abattoir if they were born in Romania, Bulgaria, or any non-EU country and they were older than 30 months and healthy at the time of slaughter
• BSE testing of bovine animals that are fallen stock, were sent for emergency slaughter or showed signs of sickness when examined by a veterinarian before death that were born in Romania, Bulgaria or any non-EU country and were older than 24 months at the time of death.