Governments outside of England began to ban British beef. Although the British government at first claimed that there was no possible harm to humans from the disease, eventually the government had to admit that its scientists had identified a series of new cases of an unusual variant on CJD, one that struck young people instead of older ones. The strong suspicion was that the new form of CJD was actually a human version of mad cow disease. Like other prion-related diseases, the new CJD is invariably fatal. In addition to kuru and Creutzfeldt-Jakob disease, prions or slow viruses are thought to be the cause of several other rare human diseases.
Patients gradually lose their coordination.
Later they develop dementia followed by death. Like GSS and CJD, FFI is invariably fatal. As the name suggests, the disease begins with inability to sleep. The widespread, but uncommon, prion-linked diseases CJD, GSS, and FFI are all partly inheritable. Although there is a lot of evidence in favor of the prion hypothesis, it is all circumstantial.