Thousands more could be carrying vCJD, say scientists

The brain disease variant CJD, triggered by eating BSE-infected meat, may have infected thousands more people than previously thought, scientists say.

Tests on tissue samples have shown that a wider group of the human population may be carrying the infection without showing symptoms and could transmit it via blood transfusions or contaminated surgical instruments.

The warning comes from researchers at the National CJD Surveillance Unit at the University of Edinburgh who checked more than 12,000 samples of tissue from tonsils and appendices removed in operations between 1996 and 1999. All the samples came from patients aged 20 to 29. Two samples harboured prion proteins - indicating vCJD infection - taken from people with a genetic make-up that had not previously been thought susceptible to the disease.

The finding raises the possibility that a second wave of cases could emerge years or even decades after the first if the incubation period in the new group of infected people is longer.

So far 161 people in the UK have succumbed to the incurable infection which slowly destroys the brain and leads to death. All cases so far identified have occurred in people carrying the methionine MM genotype, which is present in 40 per cent of the population.

The two new cases were found in tissue samples with the valine VV genotype, which is present in 10 per cent of the population. But no one with this genetic make-up has developed the disease, raising the possibility that they may be asymptomatic carriers who could pass it on via blood. The rest of the population carry the methionine/valine MV genotype.

Professor James Ironside, head of clinical neuropathology at the Edinburgh unit, said: "The fact that both these tissue specimens turned out to belong to the rarest of the genotypes in the population was surprising. It may be that they have a very long incubation period or never develop the disease but remain in a carrier state with the potential to infect others.

"People ask why, after widespread exposure to BSE in the 1980s, there have not been more cases of vCJD. The answer may be that more are infected but the infections haven't appeared yet or may never appear. The incubation period may be 40 to 50 years."

Estimates of the eventual size of the human epidemic have ranged up to hundreds of thousands of people infected but most scientists hoped that 10 years since the first human cases were identified, we were now over the worst.

The findings will increase pressure on the Government to change the rules for post-mortems to include tests for vCJD, which cannot be detected until after death.

Drug companies are racing to develop a screening test which could be used for blood donors to detect the presence of the disease before symptoms develop. However, this would raise ethical problems over the detection of a condition for the protection of others but which has no treatment.

Life and Style
ebookNow available in paperback
ebookPart of The Independent’s new eBook series The Great Composers
Mia Freedman, editorial director of the Mamamia website, reads out a tweet she was sent.
Arts and Entertainment
The write stuff: masters of story-telling James Joyce, left, and Thomas Hardy
books...begging to differ, John Walsh can't even begin to number the ways
Jose Mourinho on Sky Sports
footballEXCLUSIVE COLUMN Paul Scholes: It was not a leg-breaking tackle, as the Chelsea manager had claimed
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating

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

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Brand Manager

    Negotiable: Recruitment Genius: Do you wish to be part of an exciting journey ...

    Guru Careers: Talent Manager

    £30-35k (P/T - Pro Rata) + Benefits: Guru Careers: We are seeking an experienc...

    Recruitment Genius: Print / Warehouse Operative

    £17000 per annum: Recruitment Genius: This is a fantastic opportunity to join ...

    Beverley James: Accounts Assistant

    £23,000: Beverley James: Are you looking to join a finance team shrouded in th...

    Day In a Page

    HIV pill: Scientists hail discovery of 'game-changer' that cuts the risk of infection among gay men by 86%

    Scientists hail daily pill that protects against HIV infection

    Breakthrough in battle against global scourge – but will the NHS pay for it?
    How we must adjust our lifestyles to nature: Welcome to the 'Anthropocene', the human epoch

    Time to play God

    Welcome to the 'Anthropocene', the human epoch where we may need to redefine nature itself
    MacGyver returns, but with a difference: Handyman hero of classic 1980s TV series to be recast as a woman

    MacGyver returns, but with a difference

    Handyman hero of classic 1980s TV series to be recast as a woman
    Tunnel renaissance: Why cities are hiding roads down in the ground

    Tunnel renaissance

    Why cities are hiding roads underground
    'Backstreet Boys - Show 'Em What You're Made Of': An affectionate look at five middle-aged men

    Boys to men

    The Backstreet Boys might be middle-aged, married and have dodgy knees, but a heartfelt documentary reveals they’re not going gently into pop’s good night
    Crufts 2015: Should foreign dogs be allowed to compete?

    Crufts 2015

    Should foreign dogs be allowed to compete?
    10 best projectors

    How to make your home cinema more cinematic: 10 best projectors

    Want to recreate the big-screen experience in your sitting room? IndyBest sizes up gadgets to form your film-watching
    Manchester City 1 Barcelona 2 player ratings: Luis Suarez? Lionel Messi? Joe Hart? Who was the star man?

    Manchester City vs Barcelona player ratings

    Luis Suarez? Lionel Messi? Joe Hart? Who was the star man at the Etihad?
    Arsenal vs Monaco: Monaco - the making of Gunners' manager Arsene Wenger

    Monaco: the making of Wenger

    Jack Pitt-Brooke speaks to former players and learns the Frenchman’s man-management has always been one of his best skills
    Cricket World Cup 2015: Chris Gayle - the West Indies' enigma lives up to his reputation

    Chris Gayle: The West Indies' enigma

    Some said the game's eternal rebel was washed up. As ever, he proved he writes the scripts by producing a blistering World Cup innings
    In Ukraine a dark world of hybrid warfare and murky loyalties prevails

    In Ukraine a dark world of hybrid warfare

    This war in the shadows has been going on since the fall of Mr Yanukovych
    'Birdman' and 'Bullets Over Broadway': Homage or plagiarism?

    Homage or plagiarism?

    'Birdman' shares much DNA with Woody Allen's 'Bullets Over Broadway'
    Broadchurch ends as damp squib not even David Tennant can revive

    A damp squib not even David Tennant can revive

    Broadchurch, Series 2 finale, review
    A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower: inside the mansion of Germany's 'Bishop of Bling'

    Inside the mansion of Germany's 'Bishop of Bling'

    A Koi carp breeding pond, wall-mounted iPads and a bathroom with a 'wellness' shower