United Kingdom BSE outbreak

United Kingdom BSE outbreak
A plaque with gold letters on a black background saying "In loving memory of the victims of Human BSE (vCJD) – Always in our thoughts – Human BSE Foundation"
A plaque memorialising those who died of vCJD.
DiseaseBovine spongiform encephalopathy (BSE) and its human form; Variant Creutzfeldt–Jakob disease (vCJD)
PathogenPrions
SourceMeat-and-bone meal (MBM) in contaminated cattle feed
LocationUnited Kingdom
First reportedSeptember 1985 (BSE)
May 1995 (vCJD)
Confirmed cases181,122 (BSE)
178 (vCJD)
Deaths
178

The United Kingdom BSE outbreak was a major epidemic of bovine spongiform encephalopathy (BSE; commonly known as "mad cow disease"), an invariably fatal neurodegenerative disease in cattle, and its human form, variant Creutzfeldt–Jakob disease (vCJD). As of April 2023, the outbreak has led to 181,122 confirmed cases of BSE in Great Britain, alongside 178 diagnosed human cases of vCJD.[1]

The outbreak saw the agricultural industry cull over four million head of cattle in an effort to contain the disease, and British beef exports were banned by a number of countries including the European Union, with some bans remaining in place until as late as 2020.[2] It also led to a public health and political crisis, when vCJD in humans was linked to the consumption of beef contaminated with prions — the infectious agent associated with BSE and other transmissible spongiform encephalopathies (TSEs).[1]

The practice of supplementing protein in cattle feed with meat-and-bone meal (MBM) manufactured from the remains of animals including other cattle, and sheep infected with scrapie, a similar prion disease, exacerbated the initial spread of BSE.[3] The zoonotic human variant of the disease, vCJD, is thought to have been transmitted by using mechanically recovered meat in food products, which allowed infected brain, spinal cord, and offal tissues from cows to enter the human food chain.[4][5]

Background

British agriculture in the late twentieth century

Agriculture was the leading sector of the British economy until the mid-nineteenth century, when the repeal of the Corn Laws led to an influx of imported food. This reliance on imports, compounded by an increasing population, left it strategically vulnerable during both World Wars; after World War II, the government adopted protectionist policies to reduce this vulnerability and sustain rural areas. This was strengthened in some respects following the United Kingdom's accession to the European Communities in 1973, which provided subsidies to farmers through the Common Agricultural Policy.[6]

By the 1980s, cattle farming was the largest sector of British agriculture, comprising up to 38 per cent of the United Kingdom's entire agricultural production, and providing the vast majority of domestic demand for beef and dairy, as well as significant exports of beef and cheese.[7][8] Cattle feeds derived from animal sources had been used since the early twentieth century, compounded by the inadequate production of vegetable protein feeds, and tariffs on grains, which made animal proteins more competitively priced.[9][10]

Origin and spread of BSE

A cow slumped forward in a stable facing the left of the photograph
A cow with BSE which has lost her ability to stand, becoming a downer.

Bovine spongiform encephalopathy (BSE) belongs to a group of transmissible spongiform encephalopathies (TSEs), neurodegenerative diseases caused by the structural modification of a proteinaceous agent mainly found in nervous tissue, the prion (PrPC) protein.[11] The form of protein (PrPSc) which is associated with TSEs is also resistant to denaturation, and there is debate as to its exact role in causing prion diseases.[11][12]

Clinical symptoms of BSE include abnormal behaviour, poor co-ordination, weight loss, and eventual paralysis.[13][14] The incubation period for classical BSE is 4–6 years, and after the onset of symptoms the animal deteriorates until death, which is usually within 3 months.[12][15]

Whilst the origin of the disease remains uncertain, some earlier theories suggested that it came from the infection of cattle with scrapie, a TSE found in sheep. However, scrapie is distinguishable from BSE in the molecular profile and deposition patterns of PrPSc.[12]

The spread of BSE was only amplified by the supplementation of dairy cattle feeds with meat-and-bone meal (MBM), made using waste products from animal carcasses, including the remains sheep and cattle.[16] In the late 1970s, tallow became less expensive, and hydrocarbons were largely removed from the rendering process, resulting in a MBM product in which infectious material may have remained active.[16][17] That beef herds were given such feeds less than dairy herds ultimately proved immaterial; as most British beef came from dairy cattle.[18]

Timeline of outbreak

1980s: First cases of BSE in cattle

Evolution of the Bovine spongiform encephalopathy (BSE) epidemic in the UK.

The earliest suspicions of BSE were on a farm in Sussex in December 1984,[19] and the earliest confirmed case was by a post-mortem examination of a cow from the same farm in September 1985, although it was not confirmed as such until June 1987.[20]

By November 1987, the British Ministry of Agriculture accepted it had a new disease on its hands.[21][22] In 1989, high-risk foodstuffs like offal were banned for human consumption and widespread fear about beef led many British consumers to stop purchasing it.[23]

1990–1994: Spread to other animals

A crucial basis for the government's assurances that British beef was safe was the belief that BSE-infected meat products would not be able to infect other animals. This was founded on their experience with scrapie-infected sheep, which had proven unable to cause any illness in humans.[24][25]

Following the recommendations of the Southwood Committee, officially the Working Party on Bovine Spongiform Encephalopathy (BSE), the National CJD Surveillance Unit was set up at Western General Hospital in Edinburgh.[26]

However, scientists studying BSE were already questioning this assumption and, on 10 May 1990, it was widely reported that a Siamese cat named Max had become infected with BSE, providing the first confirmation outside the laboratory that BSE could in fact be transmitted between species through eating infected meat.[27] Despite this, the government maintained that British beef was safe and, later that month, the then-Secretary of State for Environment, Food and Rural Affairs, John Gummer, appeared on television encouraging his daughter to eat a beef burger, and declared British beef to be 'completely safe'.[28] Many more cats would go on to develop the disease, as would numerous other animals including at least one tiger in a UK zoo.[29]

Cases of the disease in cattle continued to rise despite bans on feeding offal to cows, and peaked with 100,000 confirmed cases in 1992–1993. In an attempt to stop the spread of the disease, a total of 4.4 million cattle were slaughtered during the outbreak.[23]

1994–1996: Spread to humans

Deaths in the UK caused by vCJD from the start of the BSE outbreak up until 2009. MM and MV refer to the two genotypes of vCJD.[30]

In late 1994, a number of people began to show symptoms of a neurological disease similar to CJD, a fatal disorder that occurs naturally in a small percentage of people, though usually only later in life. This new form of the disease would go on to be identified as variant CJD (vCJD), occurring primarily in younger people and caused through eating BSE-infected meat.[31] The first known death from vCJD occurred on 21 May 1995, when the 19-year old Stephen Churchill died[32][33] although the UK government continued to emphasise the safety of British beef and, in September 1995, concluded that there was 'insufficient evidence' to link BSE and vCJD.[34] It was not until 20 March 1996 that Stephen Dorrell, the Secretary of State for Health announced that vCJD was linked to eating BSE-infected meat.[35]

According to the National CJD Surveillance Unit, 178 people (the most recent case in 2016) would go on to contract and die of the disease.[36]

Regulations and bans of British beef

When BSE was identified, the United States banned the importation of British cattle in 1989, and 499 cows who had been recently imported from the United Kingdom were killed. The United States slaughtered an additional 116 British cows in 1996.[37]

In the United States between 1999 and 2022, people who lived or worked in, or who visited the United Kingdom, France, or Ireland, or who served at military bases in Europe between 1980 and 2001, or who received blood transfusions in those countries since 1980 were forbidden from donating blood. The over-two-decade donation ban in the United States on those people was finally lifted in 2022.[38]

Between December 1997 and November 1999, the British government banned the sale of beef on the bone.[39]

A week after Dorrell's announcement, on 27 March 1996, the European Union (EU) imposed a worldwide ban on exports of British beef.[39] The ban lasted for 10 years being lifted on 1 May 2006, although restrictions remained on British beef containing vertebral material and beef sold on the bone.[40] The ban lead to trade disputes between the UK and other EU states, dubbed a "Beef War" by media.[41] France continued to impose a ban on British beef illegally long after the European Court of Justice had ordered it to lift its blockade, although it has never paid any fine for doing so.[42]

The BSE inquiry

During the height of the crisis, as well as after cases began to decline, the UK government came under criticism for its response, and in particular for how slow it was to acknowledge the problem, to inform the public and to take steps to deal with the outbreak.[43]

On 22 December 1997, an inquiry was announced in parliament to investigate the history of the outbreak and the actions taken in response. The inquiry was conducted by a committee consisting of Lord Phillips of Worth Matravers, June Bridgeman and Malcolm Ferguson-Smith.

During the inquiry, microbiologist and clinical virologist Harash Narang asserted that the link between BSE and Variant Creutzfeldt–Jakob disease (vCJD) could have been established six years earlier if research had not been stopped.[44]

It provided its report in October 2000, and the report was published in full by Nick Brown, the secretary for agriculture at the time.[43] The inquiry report was critical of the government, the Ministry of Agriculture, Fisheries and Food and Chief Medical Officer Sir Donald Acheson.[45]

Future risk

The original outbreak of vCJD only affected people with a particular genetic makeup; those who were methionine-homozygous at the PRNP codon 129 methionine/valine polymorphism. Studies of similar diseases in other parts of the world have shown that methionine-homozygous people tend to become ill relatively quickly in a first wave, while methionine-valine heterozygous and valine-homozygous people can be infected but remain asymptomatic for years or even decades.[46] This has led some researchers including Graham Jackson of University College London to warn that there could be a second wave of vCJD infections years later.[46][47]

In 2016, the first case of vCJD with heterozygosity at codon 129 was identified.[48]

See also

References

  1. 1 2 Alarcon, P.; Wall, B.; Barnes, K.; Arnold, M.; Rajanayagam, B.; Guitian, J. (April 2023). "Classical BSE in Great Britain: Review of its epidemic, risk factors, policy and impact". Food Control. 146 (published 4 November 2022): 109490. doi:10.1016/j.foodcont.2022.109490. Retrieved 30 August 2026.{{cite journal}}: CS1 maint: article number as page number (link)
  2. ↑ "UK beef exports to US resume after more than 20 years". BBC News. 2020-09-30. Retrieved 2026-08-30.
  3. ↑ Wilesmith, J. W.; Wells, G. A.; Ryan, J. B.; Gavier-Widén, D. (June 1997). "Bovine spongiform encephalopathy (BSE)". Methods in Molecular Medicine. 16: 407–424. doi:10.1385/0-89603-407-7:407. PMID 9169904. Retrieved 30 August 2026.
  4. ↑ Brown, P.; Will, R. G.; Bradley, R.; Asher, D. M.; Detwiler, L. (November 2001). "Bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease: background, evolution, and current concerns". BMJ. 323 (7323): 1232–1235. doi:10.1136/bmj.323.7323.1232. PMC 1120011. PMID 11719417. Retrieved 30 August 2026.
  5. ↑ Cooper, J. D.; Bird, S. M.; de Angelis, D. (January 2003). "UK dietary exposure to BSE in beef mechanically recovered meat: by birth cohort, gender, and calendar period". Statistical Methods in Medical Research. 12 (1): 49–61. doi:10.1177/096228020301200104. PMID 12501956. Retrieved 30 August 2026.
  6. ↑ Inquiry Report, Vol. 1 §120
  7. ↑ Fearne, Andrew (May 1999). Building partnerships in the meat supply chain: The case of the UK beef industry (Report). Report 3.99.05. The Hague: Agricultural Economics Research Institute (LEI). ISBN 90-5242-508-6. Retrieved 31 August 2026.
  8. ↑ Inquiry Report, Vol. 1 §119
  9. ↑ "Economic Impacts of Regulatory Responses to BSE". www.thebeefsite.com. United States Department of Agriculture Economic Research Service. 10 November 2008. Retrieved 2026-08-30.
  10. ↑ Inquiry Report, Vol. 1 §122
  11. 1 2 Tyshenko, M. G. (2014). "Bovine Spongiform Encephalopathy". Encyclopedia of Food Microbiology (Second ed.). Academic Press / Elsevier. doi:10.1016/B978-0-12-384730-0.00043-4. Retrieved August 31, 2026. ...
  12. 1 2 3 McManus, Linda M.; Mitchell, Richard N., eds. (2014). Pathobiology of Human Disease: A Dynamic Encyclopedia of Disease Mechanisms. Academic Press / Elsevier. ISBN 978-0-12-386457-4. Retrieved September 1, 2026.
  13. ↑ Casalone, C; Hope, J (2018). "Atypical and classic bovine spongiform encephalopathy". Human Prion Diseases. Handbook of Clinical Neurology. Vol. 153. pp. 121–134. doi:10.1016/B978-0-444-63945-5.00007-6. ISBN 978-0-444-63945-5. PMID 29887132.
  14. ↑ Wild, David, ed. (2013). The Immunoassay Handbook: Theory and Applications of Ligand Binding, ELISA and Related Techniques (Fourth ed.). Elsevier Science / Academic Press. ISBN 978-0-08-097037-0. Retrieved September 1, 2026.
  15. ↑ "Bovine spongiform encephalopathy". WHO. November 2002. Archived from the original on 2012-12-18. Retrieved 27 October 2018.
  16. 1 2 Cann, Alan J. (2012). "Subviral Agents: Satellites, Viroids, and Prions". Principles of Molecular Virology (Fifth ed.). Academic Press / Elsevier. ISBN 978-0-12-384939-7. Retrieved September 1, 2026. ...
  17. ↑ Wilesmith, J. W.; Ryan, J. B. M.; Atkinson, M. J. (1991). "Bovine spongiform encephalopathy: epidemiological studies on the origin". The Veterinary Record. 128 (9): 199–203. doi:10.1136/vr.128.9.199. PMID 1823120. Retrieved September 1, 2026.
  18. ↑ Inquiry Report, Vol. 1 §123
  19. ↑ Inquiry Report, Vol. 3 §1.9
  20. ↑ Inquiry Report, Vol. 3 §1.7
  21. ↑ Pain, Stephanie (5 November 1987). "Brain disease drives cows wild". NewScientist. Retrieved 7 December 2018.
  22. ↑ "Mad Cow Disease Fast Facts". CNN. 2 July 2013. Retrieved 12 July 2019.
  23. 1 2 "'Mad cow disease': What is BSE?". BBC. 18 October 2018. Retrieved 12 July 2019.
  24. ↑ Ridley, RM; Baker, HF (21 June 1999). "Big decisions based on small numbers: lessons from BSE". The Veterinary Quarterly. 21 (3): 86–92. doi:10.1080/01652176.1999.9695000. PMID 10427633.
  25. ↑ Sample, Ian (10 January 2007). "Should we still be worried?". The Guardian. Retrieved 15 July 2019.
  26. ↑ Southwood Committee (1989). Report of the Working Party on Bovine Spongiform Encephalopathy (Report). London: Department of Health and Ministry of Agriculture, Fisheries and Food.
  27. ↑ Ainsworth, Claire; Carrington, Damian (25 October 2000). "BSE disaster: the history". New Scientist.
  28. ↑ Nelson, Sarah (11 July 2019). "'Mad Cow Disease': Symptoms, Outbreaks And Everything You Need To Know". Huffington Post. Retrieved 12 July 2019.
  29. ↑ Pattison, James (1998). "The emergence of bovine spongiform encephalopathy and related diseases". Emerging Infectious Diseases. 4 (3): 390–394. doi:10.3201/eid0403.980311. PMC 2640268. PMID 9716952.
  30. ↑ Garske, Tini; Ghani, Azra C. (23 December 2010). "Uncertainty in the Tail of the Variant Creutzfeldt-Jakob Disease Epidemic in the UK". PLOS ONE. 5 (12) e15626. Bibcode:2010PLoSO...515626G. doi:10.1371/journal.pone.0015626. PMC 3009744. PMID 21203419.
  31. ↑ Meikle, James (27 October 2000). "Sad and painful decline of a daughter". The Guardian. Retrieved 12 July 2019.
  32. ↑ Arthur, Charles (19 March 1997). "Agonising decline that led to first diagnosis of new illness". The Independent. Retrieved 16 June 2023.
  33. ↑ Wells, Chloe (Jan 16, 2022). "The 'Mad Cow Disease' Scandal". Medium. Retrieved Jun 16, 2023.
  34. ↑ Beck, Matthias; Kewell, Beth; Asenova, Darinka (2007). "BSE crisis and food safety regulation: a comparison of the UK and Germany" (PDF). Archived from the original (PDF) on 20 February 2019. Retrieved 12 July 2019.
  35. ↑ "The government acknowledged the possible link between BSE in cows and CJD in humans". Policy Navigator. Archived from the original on 12 July 2019. Retrieved 12 July 2019.
  36. ↑ "Creutzfeldt-Jakob disease in the UK (By Calendar Year)" (PDF). National CJD Research and Surveillance Unit. January 8, 2024. Archived from the original (PDF) on 14 December 2024. Retrieved 10 January 2024.
  37. ↑ Sheen, p. 65
  38. ↑ Aleccia, Jonel (2022-11-20). "No more mad cow worries, banned blood donors can give again". Associated Press.
  39. 1 2 "BSE crisis: timeline". The Guardian. 26 October 2000. Retrieved 12 July 2019.
  40. ↑ "End to 10-year British beef ban". BBC News. 3 May 2006.
  41. ↑ "EU beef war escalates". CNNfn. 22 October 1999. Archived from the original on December 9, 2001. Retrieved 4 June 2018.
  42. ↑ Sparks, Ian (6 November 2008). "Yes, we had mad cow disease too, France confesses". Evening Standard. Retrieved 23 September 2017.
  43. 1 2 Ahmed, Kamal; Barnett, Anthony; Millar, Stuart (29 October 2000). "Madness". The Observer. Retrieved 12 July 2019.
  44. ↑ "The offal truth on BSE meat scandal". The Herald. 1998-09-23. Retrieved 2026-03-18.
  45. ↑ "From nannyism to public disclosure: the BSE Inquiry report". Canadian Medical Association Journal. 164 (2): 165. 23 Jan 2001. PMC 80663. PMID 11332300.
  46. 1 2 MacKenzie, Debora (18 January 2017). "Many more people could still die from mad cow disease in the UK". New Scientist. Retrieved 16 July 2019.
  47. ↑ Toolis, Kevin (22 September 2001). "Epidemic in waiting". The Guardian. Retrieved 16 July 2019.
  48. ↑ Mok, Tzehow (19 January 2017). "Variant Creutzfeldt–Jakob Disease in a Patient with Heterozygosity at PRNP Codon 129". New England Journal of Medicine. 376 (3): 292–294. doi:10.1056/NEJMc1610003. PMID 28099827.

Works cited

  • Phillips, Nick; Bridgeman, June; Ferguson-Smith, Malcolm (October 2000). The BSE Inquiry (Report). Archived from the original on 2 August 2006. Retrieved 12 July 2019.
  • Sheen, Barbara (2005). Mad cow disease. San Diego, CA: Lucent Books. ISBN 978-1-59018-635-0 – via Archive.org.
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