October 18, 2018

expert reaction to BSE found on Aberdeenshire farm

Reactions to reports that Bovine Spongiform Encephalopathy (BSE) has been found on a Scottish farm.

Dr Simon Clegg, Lecturer in Bioveterinary Science at the University of Lincoln, said:

“The discovery of a new BSE case in Scotland is of concern but unlikely to develop on the scale the large outbreak of the 1980’s and 90s. At the “tail” of the previous epidemic this is not unexpected and highly likely to be an isolated case.  As such, there is absolutely no need to panic.  Previous control measures, including a ban on feeding animal protein to cows, remain in force and abattoirs work to very high standards, ensuring that the risk of infection to humans remains very low. This means that Scottish beef is as safe now as it ever has been. Cases of different diseases regularly emerge and disappear as fast as they arrive, in both the animal and human population, usually without widespread issues. The case is being dealt with appropriately, and there are currently no wider concerns. However, farmers will remain vigilant as always, and report any unusual clinical signs to the appropriate authorities for investigations.”

Prof Neil Mabbott, Personal Chair in Immunopathology at The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, said:

“Bovine spongiform encephalopathy, commonly known as ‘mad cow disease’ is a deadly brain condition in cattle that is caused by infection with prions.  Prions are infectious proteins with abnormal shapes and once they enter the brain they cause extensive brain damage.

“Currently no cures are available to treat prion diseases.

“Scientists consider BSE originally occurred in UK cattle through the feeding of infected meat and bone meal. During the UK outbreak in the 1980s and early 1990s, it is estimated that up to half a million cattle may have been infected in this way.

“As a consequence of this outbreak, feeding infected material to animals was banned in the UK. This has substantially reduced the incidence of further BSE cases in UK cattle.

“Very occasionally, BSE can sometimes also occur sporadically in the cattle population – causing a disease known as atypical BSE – and is not acquired as an infection. This has been the cause of many of the recent cases of the disease in the UK.

“In extremely rare cases, BSE can be passed between people and animals by eating contaminated meat, causing the disease variant Creutzfeldt-Jakob disease (vCJD).

“However, since 1989, animal tissues where the BSE prion proteins are concentrated – the brain, spinal cord and spleen – have been banned from the human food chain. This has helped to substantially reduce the risk of further disease transmission to humans with only occasional isolated cases identified in recent years.

“Fortunately, reports of vCJD in people remain very rare – in the UK there have been only 178 recorded cases, and no new ones have been reported since 2016.

“While the identification of a new case of BSE in Scottish cattle is worrying, the measures that remain in place in the UK should ensure that there is no risk to the public.

“Clearly urgent research is now required to identify the potential source and characteristics of the BSE in this outbreak.”

Dr Steven Van Winden, Senior Lecturer in Production Animal Medicine at the Royal Veterinary College, said:

“To me this means that the surveillance that has been in place for quite a few years is actually working. All cows that die over an age of 48 months will be tested with a test for the BSE prion in the brain of these fallen stock.

“This cow could be a sporadic case, or one through vertical transmission, or the beginning of a new outbreak of BSE. The latter is unlikely as cows are by law strict vegan following the BSE episode in the 80-ies. Because of the route of potential transmission the cohorts she stayed with (fellow cows) as well as her off spring will be traced and tested to make sure there is better understanding of the origin of the case. This is standard protocol following EU regulations. Results on these are pending, I believe, all we know at this stage is that the case in Aberdeenshire is confirmed BSE.

“From a human health point of view, all adult cows’ brains, spinal cords and certain lymph tissue is removed during the slaughtering process, as per routine. This is to prevent the exposure of consumers with the prions.

“To a degree the current case is business as usual, with further follow-up testing to understand the origin of the case, and for a veterinarian with an interest in epidemiology this is exciting to see the system work and hoping for this cow to be, as expected, a sporadic, isolated case.”

Prof Colin Smith, Director of the National CJD Research & Surveillance Unit at the University of Edinburgh, said:

“There are unlikely to be implications for human health as a result of this isolated case. Variant CJD – the human form of BSE – remains an extremely rare disease, and there have been no cases in the UK since 2016. None of the 178 people that have been affected by vCJD in the UK was born after 1989, which is when high-risk tissues such as brain and spinal cord were banned from the food chain. Robust controls continue to be in place to protect against a risk of transmission to humans.”

Prof Matthew Baylis, Chair of Veterinary Epidemiology at the University of Liverpool, said:

“The epidemic of Bovine Spongiform Encephalopathy (BSE) in cattle in the UK is largely over but there is still the occasional detected case – one in 2014, two in 2015 and now one in 2018.   It is too early to say if this case is significant.  It is described as ‘classical BSE’, like the vast majority of cases we have seen in the UK. This form of BSE is acquired by cattle from BSE-contaminated food.  At this stage, we need to know if it was a very old animal, infected long ago; or if it is younger and there is still an active source of infection on the farm, such as a contaminated feed bin. The agent that causes BSE, and related diseases, can remain infectious in the environment for a very long time, even decades, and so odd cases are probably to be expected.  This particular animal did not enter the human food chain; but it is important to remember that at its peak the UK recorded nearly 37,000 BSE cases in one year, while the number of deaths of people from the human form, called variant CJD, is fewer than 200. The risk to the public from a single case of BSE has proven to be exceedingly small.”

Declared interests

None received.