Histopathological and immunohistochemical features of natural goat scrapie

Abstract

Histopathological and immunohistochemical examinations were performed on the brain and spinal cord of 37 goats from two Greek herds in which scrapie had been reported. Of the 37 animals, 18 were from a herd consisting only of goats and 19 were from a herd of goats mixed with sheep. The goats studied were grouped on the basis of the presence or absence of clinical signs. Distinctive lesions and PrPSC (PrP, prion protein) deposition were found in the central nervous system (CNS) of eight clinically affected animals and six symptomless animals. The lesion profile and PrPSC distribution varied both between and within groups, variation being particularly pronounced in the symptomless goats. The results concerning the latter group suggested a poor correlation between the intensity of lesions, the amount of PrPSC in the CNS, and the manifestation of clinical signs. Immunohistochemical examination revealed 10 different PrPSC types, four of which are reported for the first time in goats. All scrapie-affected animals carried the VV21II142HH143RR154 genotype, with the exception of two goats that carried the HR143 dimorphism and had detectable PrPSC deposits. The results suggest that the histopathological and immunohistochemical profile of the natural disease in goats is influenced by the PrP genotype and age of the animals but may not be directly associated with the presence or otherwise of clinical signs. (c) 2006 Elsevier Ltd. All rights reserved.