First case of feline spongiform encephalopathy in a captive cheetah born in France: PrP^sc analysis in various tissues revealed unexpected targeting of kidney and adrenal gland

Feline spongiform encephalopathy (FSE), affecting domestic and captive feline species, is a prion disease considered to be related to bovine spongiform encephalopathy. Here we report an immunohistological analysis of the first FSE-affected cheetah born in France. The duration of clinical signs, of which ataxia was the main one, was about 8 weeks. The distribution of abnormal prion protein (PrP^sc) was studied by immunohistochemistry within 27 different tissues. Different antibodies were used to visualise abnormal PrP deposits in situ. PrP^sc accumulation was detected in the central nervous system (cerebral cortex, cerebellum, brain stem, spinal cord, retina), in peripheral nerves and in lymphoid organs. PrP^sc deposits were not observed within the enteric nervous system nor in several other organs, such as pancreas, ovary, liver and muscle. More interestingly, unusual PrP^sc deposits were observed within the zona fasciculata/reticularis of the adrenal gland and within some glomeruli of the kidney raising the question of possible PrP^sc excretion. The sympathetic innervation of these two organs was visualised and compared to the distribution of PrP^sc deposits. Our results suggest the possibility that the infectious agent is spread by both haematogenous and nervous pathways.