Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disorder of cattle characterized by the accumulation of the disease-associated prion protein (PrPSc) in the central nervous system (CNS). The immunohistochemical patterns and distribution of PrPSc were investigated in CNS, brain, and spinal cord tissue from 7 naturally occurring BSE cases confirmed by the fallen stock surveillance program in Japan. None of the animals showed characteristic clinical signs of the disease. Coronal slices of 14 brain areas from each case were immunohistochemically analysed using an anti-prion protein antibody. Immunolabelled PrPSc deposition was widely observed throughout each brain and spinal cord. Intense PrPSc deposition was greater in the thalamus, brainstem, and spinal cord of the gray matter than in the neocortices. The topographical distribution pattern and severity of PrPSc accumulation were mapped and plotted as immunohistochemical profiles of the brain areas along the caudal-rostral axis. The distribution pattern and severity of the immunolabelled PrPSc in the CNS were almost the same among the 7 cases analysed, suggesting that the naturally occurring cases in this study were at a preclinical stage of the disease. Immunohistochemical mapping of the PrPSc deposits will be used to clarify the stages of BSE in cattle.
(Prion Disease Research Center)
Okada H. et al (2011) J. Vet. Med. Sci. 73(11):1465-1471