LONDON, June 22 ? The incubation period for human prion diseases such as variant Creutzfeldt-Jakob (CJD) may be longer than 60 years, according to researchers who studied the closely related disease kuru in former cannibals in New Guinea.
The findings suggest that an epidemic of variant CJD could crop up decades from now, with the aging of people who in the 1990s consumed beef from cows infected with bovine spongiform encephalopathy (BSE), also known as mad-cow disease, wrote John Collinge, Ph.D., a professor of neurology at University College London, and colleagues in Australia and Papua New Guinea.
In fact, the incubation period for variant CJD could be even longer than that of kuru, the investigators wrote in the June 24 issue of The Lancet, because of a species-barrier effect that typically slows the rate of interspecies transmission.
Dietary exposure of the British population to BSE prions has been widespread, they wrote. The cattle epidemic is thought to have affected two million animals. Cattle BSE has also been reported in most European Union countries, Israel, Switzerland, Canada, the U.S, and Japan. So far, about 160 variant CJD patients have been identified in Britain, with cases also reported in France, Italy, Ireland, The Netherlands, Canada, Japan, and the U.S.