Aetiology

We still don't know what's going on with Idaho, where there have been 9 suspected cases of Creutzfeldt-Jakob disease in 2005.

Let me back up a bit. CJD comes in several forms. It can be inheirited, it can appear spontaneously, or it can be acquired (so-called "variant" CJD). It's the latter form--"mad cow disease," or if you want to be technical, bovine spongiform encephalopathy, that has made most of the headlines, as an outbreak occurred in Britain due to contaminated beef (more on that here). Typically, the variant form has affected young people, while the other forms affect those who are older. So far, we don't know of any variant forms which originated in the United States. (One man was diagnosed with vCJD in Florida, but he had previously lived in the UK, and it's assumed he acquired the disease there). It seems that tests are ongoing in the Idaho cases. This article from September 28th mentions:

Additional tests are under way at the lab to determine what form of CJD was responsible in the three confirmed cases.

"Generally, 85 percent of the tests come back as the sporadic, or naturally occurring form, 14 percent come back as the familial form that is passed down through generations and less than 1 percent come back as the variant form," said Tom Shanahan, spokesman for the Idaho agency.

So, why are these cases attracting national attention? As noted in the article linked above, Idaho officials have never recorded more than three cases in a single year, and the disease usually infects only one out of every 1 million people worldwide. Idaho's population is only ~1.3 million; therefore, 9 possible cases in a single year is high. It could be a statistical blip, or it could be something more dangerous. If any of these cases turn out to be vCJD, expect the news media to take a short break from all their avian flu coverage and go back to hyping mad cow disease.