The hidden killer.

An annual 150,000 people in Britain are victims of dementia or Alzheimer's disease. Dispatches examines the work of British and American scientists who believe that this figure includes cases of Creutzfeld Jakob disease (CJD). It is impossible to test for CJD on a living person - it can only be diagnosed at autopsy. However, this procedure is not normally carried out at the deaths of elderly people who have been suffering, apparently, from dementia. The National CJD Surveillance Unit at Edinburgh is co-ordinating a massive research programme to examine the brains of deceased dementia sufferers, comparing them to the brains of those who died in accidents. In the U.S. a group of people known as the Indiana Kindred carry a gene mutation which means they inevitably develop Alzheimer's as they age. Both CJD and Alzheimer's are prion diseases and the question arises as to whether they have a common cause. Studies of cows and sheep, examining bovine spongiform encephalopathy (BSE) and scrapie show that one strain of scrapie is very similar to BSE. Both produce the same physical damage to the brain and both can be transmitted by feed. The question arises as to whether BSE occurs in sheep and has hitherto been incorrectly diagnosed as scrapie. Among those taking part in the programme are Dr. James Ironside (National CJD Surveillance Unit) and Drs. Rosalind Ridley and Harry Baker (neuroscientists, Cambridge University).