Mad Cows and CJD: A Physicist's View of Prion Brain Diseases

The research of Carleton Gajdusek on a stone-age tribe in Papua New Guinea, who suffered from a mysterious disease, kuru, spread by cannibalism, is described and short extracts from his films will be shown. Some deaths from kuru are still occuring after 45 years. This disease is believed to be caused by an entirely new mechanism, not a virus or bacteria, but by a small molecule known as a prion that occurs naturally in many living forms. The Prion Only hypothesis of Stan Prusiner is discussed critically. It has been calculated that 900,000 cows in Britain had the Mad Cow disease, BSE, but most were slaughtered before symptoms were recognised. This epidemic started with 10 cases in the first year, and finally 160,000 were officially classified as having BSE; it is now slowly dying out. The human epidemic, caused by a new version of Creutzfeldt-Jakob Disease, nvCJD, affects mainly young people, has just begun with 10 cases in the first year. The average incubation time may be about 14 years then death follows in one year, so the peak in the human epidemic in Britain is expected in about 2005. The situation in other European countries and in North America is reviewed. Among subjects discussed are species barrier, public health, Alzheimer's, molecular genetics, and blood.