What is variant CJD?
It is a disease which affects relatively young people. Symptoms include disturbances in behaviour and difficulties with balance and walking. On average, people survive for 13 months after it develops. Its full name is variant Creutzfeldt-Jakob Disease and it is known as vCJD.
How does it differ from CJD?
"Classic" CJD mainly affects people over 65 and has been known for decades. Symptoms include dementia and loss of control of movement. People survive for about five months with it. There is an average of three cases a year in Ireland. Variant CJD has been identified publicly only since 1996 and affects younger people.
How widespread is vCJD?
As yet it occurs infrequently. There are 88 cases in Britain, two in France and one in the Republic, which it is believed originated in Britain.
How is it linked with BSE?
BSE, mad cow disease, and vCJD seem to have the same source. In other words, vCJD seems to be a human form of BSE. The source of infection in each case is believed to be the infectious agent known as a prion. It has been described as a "rogue protein".
Why is there increasing concern about it?
It recently emerged that between 1990 and 1996 the authorities in Britain covered up the findings that BSE could cross from cattle to humans. This may have infected an unknown number of people before stricter controls were introduced in 1996.
One of more than 60,000 donors who contributed to a pool from which an ingredient in a polio vaccine was made was recently diagnosed with vCJD. More than 50,000 Irish children got the vaccine but experts say the risk of infection is zero. In short, the persistence of the infectious prion and difficulty in eliminating it have heightened concern about BSE and vCJD.
Where are most cases located?
Most cases seem to have originated in Britain. It is not clear where the two French cases originated.
What is being done about it?
The EU is banning the feeding of meat and bonemeal (believed to have facilitated transmission of the BSE prion) to pigs and poultry for six months from January 1st. This is to allow rendering plants to ensure their technology meets the highest standards in producing safe bonemeal.
Irish rendering plants already meet these standards. In this country, bonemeal is fed to pigs in 17 locations under licence. It is not licensed for feeding to poultry (the poultry industry has a voluntary ban) and there is a ban on feeding it to cattle. The meal is made from the remains of animals which have been passed fit for human consumption.
The EU is also introducing a "purchase for destruction" scheme in which, starting next Monday, cattle older than 30 months will be bought up for slaughter to take them out of the food chain. Alternatively, they can be tested to establish that they are BSE-free.