A paper by a team in France answers some of the questions posed by this thread:

- alpha-synuclein is found in animals;

- although lewy bodies are not mentioned, "granular deposits" of alpha-synuclein are found in diseased animals.

Adjou et al. report [1]:

"Immunohistochemical examination demonstrated widespread granular deposits of alpha-synuclein (alpha SN) in the brains of sheep and goats with natural scrapie, ... The results suggest that perturbation of alpha SN metabolism plays a role in human and animal prion diseases."

Tag johnt:alpha-synuclein

Reference:

[1] "Alpha-synuclein accumulates in the brain of scrapie-affected sheep and goats"
Adjou, K. T.; Allix, S.; Ouidja, M. O.; Backer, S.; Couquet, C.; Cornuejols, M. J.; Deslys, J. P.; Brugere, H.; Brugere-Picoux, J.; El-Hachimi, K. H.
Journal of Comparative Pathology 137(1): 78-81, 2007
http://www.ncbi.nlm.nih.gov/pubmed/17544436

John