The Truth About ...; Human BSE

PROVING THAT bovine spongiform encephalopathy (BSE) has crossed the species barrier from cows to human beings has been one of the most difficult scientific problems of late-20th-century medicine. Suspicions that BSE could pass into humans were voiced soon after the disease appeared in cattle in the mid-Eighties, but collecting the evidence that finally firmed up this speculation proved to be a far harder undertaking.

Creutzfeldt-Jakob disease (CJD) is the equivalent brain disease in humans and it has been known about since the early part of this century, long before BSE. Experts came to the conclusion early on that if BSE were able to pass into humans, then there might be a rise in the cases of so-called "sporadic" CJD. This classical form of CJD occurs in people who have no family history of the disease, and it strikes without any apparent reason - hence the name. The disease is also extremely rare, occurring at a rate of about one in a million people every year. Most doctors would never come across a case of sporadic CJD in their entire careers.

To make sure the country was able to detect any rise in the incidence of CJD, the government established a national CJD Surveillance Unit in 1990, based in Edinburgh. This unit is responsible for actively seeking out any information about unusual neurological disorders, as well as determining a diagnosis to see whether it may be CJD. The unit has since proved to be a world authority on this extremely rare and unusual disease.

Each suspect case of an unusual brain disorder is investigated with immense rigour, with the scientists asking relatives detailed questions about a patient's medical history, residence and lifestyle, such as his or her occupation and diet. They document the clinical symptoms of patients and analyse their brain material for signs of the neuropathology that distinguishes CJD from other brain diseases. Genetic tests are also done to see whether there may be something in a patient's DNA that can explain why they have developed the disease.

Sporadic CJD usually affects older people, with the average age of its onset being about 64. But in the second half of 1995 the unit began to investigate suspected cases of CJD affecting people under 30, which is extremely rare. (Up until then there had been only one confirmed case in a person aged under 30 - who died in 1980, just before the BSE epidemic took off.)

When Robert Will and James Ironside, the two principal investigators at the unit, looked in more detail at the cases in young people, they found that this form of CJD showed distinct differences from the classical characteristics of the sporadic disease. Under the microscope, the brain tissue of a new variant (nv) CJD victim displays distinctive, flowery structures of protein alongside the typical spongy holes seen in people with the sporadic form of the disease. Other features of the clinical symptoms suggested to Will and Ironside that what they had here was totally new to medical science.

When 10 cases of nvCJD came to light, the government made its famous announcement in May 1996 that the "most likely" explanation was that BSE had crossed the species barrier; but the hard proof of cause and effect was still lacking. It fell to the Neuropathogenesis Unit in Edinburgh to supply this evidence, in the form of a series of experiments on strains of genetically inbred mice.

When injected with brain material of an animal suffering from a particular kind of spongiform encephalopathy (such as sheep scrapie) each mouse strain exhibits a distinctive period of incubation before succumbing to the disease. The scientists, led by Moira Bruce, found that BSE and nvCJD had an identical "signature" that was quite distinct from those of sporadic CJD and scrapie. It was the closest science could get to proving that BSE could pass into humans to cause nvCJD, which could now justifiably be called the human form of BSE.

Steve Connor

Arts and Entertainment
Characters in the new series are based on real people, say its creators, unlike Arya and Clegane the Dog in ‘Game of Thrones’
tv'The Last Kingdom' embraces politics, religion, warfare, courage, love and loyalty, say creators
Arts and Entertainment
Unless films such as Guardians of the Galaxy, pictured, can buck the trend, this summer could be the first in 13 years that not a single Hollywood blockbuster takes $300m

film
Arts and Entertainment
Miley Cyrus has her magic LSD brain stolen in this crazy video produced with The Flaming Lips

music
News
peopleThe Game of Thrones author said speculation about his health and death was 'offensive'
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment
The new film will be shot in the same studios as the Harry Potter films

books
Arts and Entertainment
Duncan Bannatyne left school at 15 and was still penniless at 29

Bannatyne leaves Dragon's Den

TV
Arts and Entertainment
The French economist Thomas Piketty wrote that global inequality has worsened

books
Arts and Entertainment
David Tennant and Benedict Cumberbatch

TV
Arts and Entertainment
Ben Affleck plays a despondent Nick Dunne in David Fincher's 'Gone Girl'

film
Arts and Entertainment
Pete Doherty (L) and Carl Barât look at the scene as people begin to be crushed

music
Arts and Entertainment

tv
Arts and Entertainment
Pete Doherty and Caral Barat of The Libertines performs on stage at British Summer Time Festival at Hyde Park

music
Arts and Entertainment
Ariana Grande and Iggy Azalea perform on stage at the Billboard Music Awards 2014

music
Arts and Entertainment

theatre
Arts and Entertainment
Zina Saro-Wiwa

art
Arts and Entertainment
All-new couples 'Come Dine With Me'

TV
Arts and Entertainment

TV
Arts and Entertainment

TV
Arts and Entertainment
Black Sabbath's Ozzy Osbourne
musicReview: BST Hyde Park, London
Arts and Entertainment
Ed Gamble and Amy Hoggart star in Almost Royal burning bright productions
tvTV comedy following British ‘aristos’ is accused of mocking the trusting nature of Americans
Arts and Entertainment
Sassoon threw his Military Cross into the Mersey
booksAn early draft of ‘Atrocities’ shows the anti-war sentiment was toned down before publication
Arts and Entertainment
Actors and technicians on the march against changes made by Hollande
theatreOpening performances of the Avignon theatre festival cancelled as actors and technicians walk out
Arts and Entertainment
Kanye West performed in a chain mail mask at Wireless Festival in Finsbury Park
Rapper booed at Wireless over bizarre rant
Arts and Entertainment

They're back, they're big – and they're still spectacularly boring

film
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    The true Gaza back-story that the Israelis aren’t telling this week

    The true Gaza back-story that the Israelis aren’t telling this week

    A future Palestine state will have no borders and be an enclave within Israel, surrounded on all sides by Israeli-held territory, says Robert Fisk
    A History of the First World War in 100 Moments: The German people demand an end to the fighting

    A History of the First World War in 100 Moments

    The German people demand an end to the fighting
    New play by Oscar Wilde's grandson reveals what the Irish wit said at his trials

    New play reveals what Oscar Wilde said at trials

    For a century, what Wilde actually said at his trials was a mystery. But the recent discovery of shorthand notes changed that. Now his grandson Merlin Holland has turned them into a play
    Can scientists save the world's sea life from

    Can scientists save our sea life?

    By the end of the century, the only living things left in our oceans could be plankton and jellyfish. Alex Renton meets the scientists who are trying to turn the tide
    Hollywood targets Asian audiences as US films enjoy record-breaking run at Chinese box office

    Hollywood targets Asian audiences

    The world's second biggest movie market is fast becoming the Hollywood studios' most crucial
    Grindr founder Joel Simkhai: 'I've found love on my dating app - and my mum keeps trying to hook me up!'

    Grindr founder Joel Simkhai: 'I've found love on my dating app'

    Five years on from its launch and Grindr is the world's most popular dating app for gay men. Its founder Joel Simkhai answers his critics, describes his isolation as a child
    Autocorrect has its uses but it can go rogue with embarrassing results - so is it time to ditch it?

    Is it time to ditch autocorrect?

    Matthew J X Malady persuaded friends to message manually instead, but failed to factor in fat fingers and drunk texting
    Westminster’s dark secret: Adultery, homosexuality, sadomasochism and abuse of children were all seemingly lumped together

    Westminster’s dark secret

    Adultery, homosexuality, sadomasochism and abuse of children were all seemingly lumped together
    A History of the First World War in 100 Moments: Dulce et decorum est - a life cut short for a poet whose work achieved immortality

    A History of the First World War in 100 Moments

    Dulce et decorum est: a life cut short for a poet whose work achieved immortality
    Google tells popular music website to censor album cover art in 'sexually explicit content' ban

    Naked censorship?

    The strange case of Google, the music website and the nudity take-down requests
    Howzat! 8 best cricket bats

    Howzat! 8 best cricket bats

    As England take on India at Trent Bridge, here is our pick of the high-performing bats to help you up your run-count this summer 
    Brazil vs Germany World Cup 2014 comment: David Luiz falls from leader figure to symbol of national humiliation

    David Luiz falls from leader figure to symbol of national humiliation

    Captain appears to give up as shocking 7-1 World Cup semi-final defeat threatens ramifications in Brazil