Prion diseases are very rare, and no treatment is available for most of them.

He believes that prion disease is caused by a virus.

However, some general characteristics of prion diseases are listed below.

Prion diseases have been found in 85 species, passing easily between some animals and not others.

In some cases, the etiology of prion diseases is known.

But in animals and people with prion diseases, one protein could not be broken down.

The most well-known prion disease to date was one that crossed between species.

There is currently no treatment for prion diseases, which are usually fatal to the host.

Since then 135 people, mostly from Britain, have died from the new prion disease.

The practice has been linked to the spread of a prion disease called kuru.