TRANSMISSIONS TO MICE INDICATE THAT NEW VARIANT CJD IS CAUSED BY THE BSE AGENT

There are many strains of the agents that cause transmissible spongifo rm encephalopathies (TSEs) or 'prion' diseases, These strains are dist inguishable by their disease characteristics in experimentally infecte d animals, in particular the incubation periods and neuropathology the y produce in panels of inbred mouse strains(1-4). We have shown that t he strain of agent from cattle affected by bovine spongiform encephalo pathy (BSE) produces a characteristic pattern of disease in mice that is retained after experimental passage through a variety of intermedia te species(5-7). This BSE 'signature' has also been identified in tran smissions to mice of TSEs of domestic cats and two exotic species of r uminant(6,8), providing the first direct evidence for the accidental s pread of a TSE between species, Twenty cases of a clinically and patho logically atypical form of Creutzfeldt-Jakob disease (CJD), referred t o as 'new variant' CJD (vCJD)(9), have been recognized in unusually yo ung people in the United Kingdom, and a further case has been reported in France(10). This has raised serious concerns that BSE may have spr ead to humans, putatively by dietary exposure, Here we report the inte rim results of transmissions of sporadic CJD and VJD to mice, Our data provide strong evidence that the same agent strain is involved in bot h BSE and vCJD.