Alzheimer's disease may be transmissible through blood transfusions and medical accidents in the same way as Creuzfeldt Jakob Disease. In a landmark finding, researchers at University College London said it was possible the ''seeds'' of dementia could be transferred from the brain tissue of one person to another.Worryingly, the proteins that cause dementia are a type called prions, which can stick to metal surfaces such as surgical instruments, and are resistant to conventional sterilisation.It means it would be theoretically possible to become infected with Alzheimer's seeds through a blood transfusion, brain surgery or invasive dental work. And because the incubation period can be up to 40 years, people could be unaware that they have been contaminated.But this did not mean that Alzheimer's was contagious, the authors and independent commentators stressed."This relates to a very special situation in which people have been injected with essentially extracts of human tissue," said co-author John Collinge."We should think about whether there might be accidental routes in which these diseases might be transmitted by medical or surgical procedures."While conducting research into an unrelated disease, Collinge and a team examined the brains of eight people who had received injections in childhood of a hormone to treat dwarfism.The hormone had been extracted from pituitary glands harvested from thousands of human cadavers.This practice was halted in 1985 when doctors realised it could transmit a variant of Creutzfeldt-Jakob - the human version of "mad cow" disease. Eight subjects in the study died from this ailment...