Human form of 'mad cow' disease twice as prevalent as previously thought, study reveals

Scientists do not know how many people may be incubating lethal disease vCJD without showing symptoms

Science Editor

Twice as many people as previously thought may be carrying the infectious agent responsible for the human form of “mad cow” disease, a study has claimed. Double the number of people were found with the unusual proteins linked to the variant form of Creutzfeldt-Jakob disease, which is believed to have passed from contaminated beef to humans.

A survey of more than 32,000 appendix samples has revealed that 16 samples were positive for the abnormal “prion proteins” found in variant CJD patients, a degenerative brain disease acquired from exposure to contaminated meat products. The appendix operations were carried out between 2000 and 2012 and the samples were taken anonymously from patients attending more than 40 hospitals in Britain in order to assess the prevalence of vCJD in the population.

So far only 177 people in the UK have been diagnosed with vCJD, along with about a further 50 patients in other countries. Scientists do not know how many people may be incubating the lethal disease without showing symptoms because as yet there is no simple blood test for prion proteins.

Scientists are assuming there is a pool of people who are incubating the brain disease because it takes many years and sometimes decades for the first symptoms to show. Estimating the size of this pool is important for assessing the risk of the infective agent spreading via blood transfusions and hospital equipment.

“These findings have important implications for the management of blood and blood products and for the handling of surgical instruments,” said Noel Gill of Public Health England and colleagues in a study published in the British Medical Journal.

The study found the risk of carrying the prion proteins was about the same for both young and old, as it was for men and women. It was also about the same for different regions of the country, the researchers said.

Sheila Bird, an epidemiologist at the Medical Research Council’s Biostatistics Unit in Cambridge, said that larger samples sizes of about 50,000 each for men and women were needed to make more accurate assessments of how many people may be unwittingly infected with vCJD prion proteins.

“After all, we’ve done BSE-testing in millions of cattle across Europe but not yet surveillance in 100,000 UK human appendices,” Dr Bird said.

Professor David Brown of Bath University, and a former member of the Government’s advisory board on BSE, said the abnormal prion protein is not only present in vCJD but in the sporadic form of the CJD that has nothing to do with bovine spongiform encephalopathy – “mad cow” disease.

“It is important to note the presence of the abnormal protein in the appendix does not confirm an individual will develop vCJD. As the authors themselves point out, the incidence of vCJD is very small in relation to those who were exposed to BSE,” he said. “Therefore this result does not indicate one in 2,000 people carry vCJD, and it could just be down to people who carry the abnormal protein in their appendix,” he said.

“This study suggests people from different age groups and from anywhere in the UK could get vCJD... At most the report suggests a broad range of people could be carriers of a prion disease, which was suspected anyway.”

Professor Azra Ghani of Imperial College London, said: “These results highlight the need to maintain both case surveillance, and precautionary measures to prevent onward transmission over the coming decade.”

Start your day with The Independent, sign up for daily news emails
PROMOTED VIDEO
ebooks
ebooksA special investigation by Andy McSmith
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

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

iJobs Job Widget
iJobs General

Tradewind Recruitment: Science Teacher

£90 - £140 per day: Tradewind Recruitment: I am currently working in partnersh...

Tradewind Recruitment: Year 3 Primary Teacher

£100 - £150 per day: Tradewind Recruitment: Year 3 Teacher Birmingham Jan 2015...

Ashdown Group: Lead Web Developer (ASP.NET, C#) - City of London

£45000 - £50000 per annum + Excellent benefits: Ashdown Group: Lead Web Develo...

Tradewind Recruitment: Key Stage 2 Teacher Required in Grays

£21000 - £40000 per annum + Negotiable: Tradewind Recruitment: Key Stage 2 tea...

Day In a Page

Isis hostage crisis: The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power

Isis hostage crisis

The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power, says Robert Fisk
Missing salvage expert who found $50m of sunken treasure before disappearing, tracked down at last

The runaway buccaneers and the ship full of gold

Salvage expert Tommy Thompson found sunken treasure worth millions. Then he vanished... until now
Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

Maverick artist Grayson Perry backs our campaign
Assisted Dying Bill: I want to be able to decide about my own death - I want to have control of my life

Assisted Dying Bill: 'I want control of my life'

This week the Assisted Dying Bill is debated in the Lords. Virginia Ironside, who has already made plans for her own self-deliverance, argues that it's time we allowed people a humane, compassionate death
Move over, kale - cabbage is the new rising star

Cabbage is king again

Sophie Morris banishes thoughts of soggy school dinners and turns over a new leaf
11 best winter skin treats

Give your moisturiser a helping hand: 11 best winter skin treats

Get an extra boost of nourishment from one of these hard-working products
Paul Scholes column: The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him

Paul Scholes column

The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him
Frank Warren column: No cigar, but pots of money: here come the Cubans

Frank Warren's Ringside

No cigar, but pots of money: here come the Cubans
Isis hostage crisis: Militant group stands strong as its numerous enemies fail to find a common plan to defeat it

Isis stands strong as its numerous enemies fail to find a common plan to defeat it

The jihadis are being squeezed militarily and economically, but there is no sign of an implosion, says Patrick Cockburn
Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action

Virtual reality: Seeing is believing

Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action
Homeless Veterans appeal: MP says Coalition ‘not doing enough’

Homeless Veterans appeal

MP says Coalition ‘not doing enough’ to help
Larry David, Steve Coogan and other comedians share stories of depression in new documentary

Comedians share stories of depression

The director of the new documentary, Kevin Pollak, tells Jessica Barrett how he got them to talk
Has The Archers lost the plot with it's spicy storylines?

Has The Archers lost the plot?

A growing number of listeners are voicing their discontent over the rural soap's spicy storylines; so loudly that even the BBC's director-general seems worried, says Simon Kelner
English Heritage adds 14 post-war office buildings to its protected lists

14 office buildings added to protected lists

Christopher Beanland explores the underrated appeal of these palaces of pen-pushing
Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

Scientists unearthed the cranial fragments from Manot Cave in West Galilee