PRION IMMUNOREACTIVITY IN BRAIN, TONSIL, GASTROINTESTINAL EPITHELIAL-CELLS, BLOOD AND LYMPH VESSELS IN LEMURIAN ZOO PRIMATES WITH SPONGIFORM ENCEPHALOPATHY

We report on two animals of a non-human primate species Eulemur fulvus mayotteniss, housed in the local zoo and fed over a number of years w ith a food containing cattle meat, that developed serious neurological symptoms associated with prion immunoreactivity in brain and various viscera. Microscopy of the brains showed neuronal vacuolation with pat chy/perivacuolar immunolabelling with an abnormal isoform of prion pro tein (IP-PRP), an important characteristic of spongiform encephalopath y. For the first itme, we report the presence in the same severely ill animals of IR-PRP in the gastrointestinal tract, detected by immunocy tochemistry with mono- and polyclonal antibodies directed against vari ous parts of the PrP. Strong PrP labelling was observed in the epithel ial cells lining the pharyngeal and gastrointestinal lumen. The tonsil s and the walls of the lymph and blood vessels below the intestinal ep ithelium were also labelled. There were no such immunoreactions in hea lthy lemurians killed as controls, i.e. a younger congener of the same species housed under the same conditions, and other belonging to the smaller species Microebus murinus, reared in the laboratory and never fed on commercial food products containing cattle meat. These results demonstrate a strong PrP accumulation in the brain, the gastrointestin al tract and underlying lymphoreticular structures in these primates l iving in a zoological park and suffering from a spongiform encephalopa thy.