Encephalopathy with Rosenthal fibre formation in a sheep.

In the brain of a 4-year-old ewe extensive Rosenthal fiber (RF) formation was found in a subpial and subependymal location and in particular in the cerebellar white matter. Here, the RFs were concentrated around blood vessels, and there was diffuse myelin rarefaction. The animal had given birth to two lambs, which were still healthy at the age of 3 weeks when their mother died after a short illness with astasia and alternating states of somnolence and hyperexcitability.