Histological lesions in central nervous system of sheep

Between January 05, 2003 and May 01, 2003 in Sanitary Veterinary Laboratory from Iaşi were examined 172 samples of brain tissue from sheep normally slaughtered for human consumption and from sheep whom slaughter were dictate by different reasons. Prior to the histopatological examination the samples were fixed in salty formalin solution 10%, included in paraffin, sliced by microtome at 5-6 μm and stained by modified HEA staining metod. The histopatological examination revealed various microscopic lesions: circulatory disorders of meninges and in nervous parenchyma (congestion, hemorrhages, edema, disseminated intravascular coagulation) in 70% of examined cases; dystrophies – 50% (vascular hyalinosis, granular or vacuolar dystrophy of perikarya, 8%, central and peripheral cromatolysis of neurons, neurophylus spongiosis, demyelination); necrobiotic lesions of neurons (neuronophagia, karyolysis, karyorexis) 70% of cases; meningeal and vascular metaplasia 5%; meningoencephalitis and encephalitis with variable degree of intensity (predominant lymphohistiocytic) 30-40%

Histopatological modifications in ovine scrapie

The suspicion   of the EST was formulated in February 2002 after examination of the brainstem belonging to two adult sheep with neurological signs and was communicated as a entity of Status spongiosus . In the next period were investigated 140 sheep from the same farm,from which 10 patients have reacted positively using ELISA/BioRad, electrophoresis and Western blotting – Prionics test in LNR; these results were confirmed immunohistologically in IRL – TSES VLA Weybridge, UK. Histopathological observations were made on nervous tissue sampling by foramen magnum rapid method, fixed in saline formaldehyde, sectioned and stained using modified HEA. Characteristic bilaterally symmetrical injuries, localised in brainstem and occasionally in other zones of the CNS, were integrated in lesional triad: vacuolisation of the perikarions, spongiosis of the neuropil in grey matter and diffuse astrogliosis. Neuronal and glial vacuoles, single or multiple, of different sizes, are well delimited, seeming empty, comparable with soap – bubbles. There are mentioned the most important elements of differential diagnosis.