What actually causes the variant form of Creutzfeldt-Jakob Disease (vCJD) to develop in young people is still unknown. The most probable cause believed is that BSE can be transmitted to humans through consumption of BSE contaminated meat. Although laboratory tests have shown a strong similarity between the prions causing BSE and vCJD, there is no final proof to support this claim. Just as there is no information to reveal the incubation time for the disease to develop. But what do we actually know about vCJD?

Some 160 people worldwide are known to have died of the variant form of Creutzfeldt-Jakob Disease (vCJD) after apparently eating BSE-infected meat [see table]. The two most recently confirmed cases of vCJD were reported in the Netherlands and Japan earlier this year. The Japanese victim is thought to have contracted the disease while staying in the U.K. for three weeks in 1990. In contrast, the Netherlands and also Ireland have reported their first home grown vCJD cases. Portugal and Germany are examining their first suspected vCJD victims with two more cases of vCJD being reported in France.

Despite a decade of intense investigation, researchers are still trying to uncover the facts about how the variant forms of CJD are transmitted; how long the disease incubates before symptoms appear; whether there is a cure for vCJD; and what steps could be taken to lessen the toll. Despite some startling discoveries that were made in recent months, one of the biggest mysteries about vCJD has been the time the disease takes to incubate. This, above all, has made it difficult to predict how many people have already been infected and what the risks associated with transmission are.

More types of CJD still unrecognized?
The normal prion protein (PrP) in humans is known to occur in two variants. All vCJD victims have so far carried the M129 variant (methionine at position 129 of the PrP amino acid sequence). The other variant, V129 (valine at position 129), is thought to be resistant to prion infection. However, recent experiments have shown that mice carrying the resistant variant of the human prion protein (V129-mice) could also become infected with a novel form of prion disease, not yet identified in humans. According to the British researchers who performed this study the results indicate that there may be types of sporadic CJD in the human population that are still unrecognized as being associated with BSE.