CJD: are we still at risk?
In 1996, we learnt with horror that UK citizens were dying from a form of incurable rare brain disease, caught from eating poor-quality meat that had been infected with the cattle disease BSE. So are we still at risk?
For what seemed an age, the issue dominated the news, but now, six years later, we hardly ever hear about Creutzfeldt-Jakob disease - CJD - and the majority of the population remains surprisingly ignorant about what it is, how it is spread or even what risk we still run of catching it. Campaigners were so concerned at this lack of knowledge, they ran CJD Awareness Day on November 12.
CJD is a fatal disease caused by infectious agents called prions, which attack the brain, killing cells and creating gaps in tissue. Early symptoms include memory loss, mood changes and lack of co-ordination. The disease progresses to shakiness and dementia and sufferers are eventually unable to move or speak.
There are actually four different forms of the disease: sporadic, variant, genetic and iatrogenic. Sporadic CJD (sCJD) is by far the most common, killing on average 46 UK citizens a year, and exists all over the world. It appears suddenly, has no known cause, tends to affect the elderly and causes death within months.
Variant CJD (vCJD) is caught from eating infected cattle and exists almost entirely within the UK. It develops slowly, affects the victim over time, is more common among the young, and causes a protracted and painful death. Between 1996 and 2001, it killed an average of 17 people a year.
Genetic CJD is caused by an inherited abnormal gene and is extremely rare - as is iatrogenic CJD, which is accidentally transmitted during the course of medical or surgical procedures. Together they kill about three people a year.
Weighing up the risks
People's main concerns lie, naturally, with vCJD. At the height of the BSE epidemic, the UK culled thousands of cattle infected with the disease and introduced extensive safety measures, but has the risk of catching vCJD disappeared? How many of us are carrying it?
The terrible thing, as Department of Health spokesman Rob Beasley explains, is that we just don't know. "There are more things we don't know about vCJD than we do," he says. "In terms of risk to the population, we don't have a clear idea of the people likely to have been affected by eating contaminated food."
Even estimates of the final number of people we can expect to die from the disease vary wildly from 200 to nearly 150,000. A recent study put it at a few thousand but added that vCJD has an average incubation time - the length of time it takes the disease to show itself - of 14 years.
Mr Beasley also explains that we have still to ascertain the level of a dose of infected meat for vCJD to develop. This, he says, could mean that by having eaten just one infected pie, someone could get the disease.
Perhaps it is unsurprising then that those trying to combat the threat of CJD are super-sensitive about talking about their progress. The National Prion Unit at St Mary's Hospital in London is one of several working hard at solving some of vCJD's mysteries. Its head, Professor John Collinge, has already linked the effect of the disease to different gene groups but much work remains to be done, not least the search for a form of cure.
Pressure on sufferers' families
But while we concern ourselves with our own risk, we should also remember those who have dealt with the disease first-hand. Gillian Turner is a gerontologist (specialising in the study of ageing) and heads up the CJD Support Network for all forms of the disease.
She says families are most often affected by sporadic CJD and that this form of the disease gets a lot of attention because vCJD became so political. However, she says the fact that sCJD gets so much media coverage isn't always a good thing. A lot of families who have a loved one who dies of sCJD, for example, find people expect them to have received a lot of compensation. Money isn't even the problem, Gillian says, it's time.
The disease can have other unexpected complications. "We are always told it is not hereditary but family members are discriminated against when they go to a dentist or give blood." Gillian says that even though CJD cases get plenty of attention, healthcare professionals still need a lot of education on the condition.
It is the ongoing uncertainties that make it worse. "You can't see it on an X-ray, you can't see it in blood. It is very difficult to diagnose and usually it is only after the post-mortem that you know for sure what it was," she says.
CJD in all its forms is a tragic disease. But with vCJD at least, we are getting some way towards tackling it. There is still no accurate test but experts believe that day is drawing closer.
Other measures, including strict screening of the blood supply, new surgical procedures and improved decontamination facilities, should help reduce the risk of contracting the disease.
National CJD Surveillance Unit - www.cjd.ed.ac.uk
CJD Foundation - www.cjdfoundation.com
CJD Support Network - www.alzheimers.org.uk/cjd