[Crazy horse disease].

With the apparition of the crazy cows disease at the end of twentieth century, great was the temptation for denominate "crazy horses disease" an ancient enzootic encephalo-myelitis, known from the 17th century and now named "Borna disease" in 1970, because severe outbreaks affecting horses in this city of Germany since 1885. But the sickness was not a prion disease but a viral one, causing also encephalopathy in several other animal species. After seventy years of investigation, the finding of the virus in human patients with psychiatric pathology in the eighties gave an incentive to work harder, and the genome structure of the so called Bornavirus was completely described. Recently, japanese investigators found that elements homologous to the nucleoprotein (N) gene of Bornavirus exist in the genomes of several mammalian species, including humans, in which these sequences have been designated endogenous Borna-like N (EBLN) elements. And now the question is what they are doing there since their integration two million years ago.