Variant Creutzfeldt-Jakob disease (vCJD) is a rare condition, occurring in about two in every one million people, writes Dr Muiris Houston, Medical Correspondent.
It is caused by a viral-type agent, called a prion, which is thought to be transferred to humans who consume BSE- infected meat.
Cases have also occurred in adolescents who, in the past, received growth hormone that had been extracted from the pituitary gland of cadavers.
Treatment for growth hormone deficiency is now manufactured synthetically, so this mechanism of vCJD transfer is no longer a concern.
The risk of transmission from surgical instruments, although extremely low, remains. The causative agent for vCJD has been isolated from tonsillar tissue but, to date, there is no recognised test by which asymptomatic carriers of the disease can be detected.
As the authors of today's report state, the development of a blood test that would allow population screening for vCJD would be helpful.
Following diagnosis, the person with vCJD rarely survives more than six months. Symptoms include muscle twitching, lack of co-ordination, personality change and dementia.
