ANATOMOPATHOLOGIC LESIONS OF EXPERIMENTAL POLIOENCEPHALOMALACIA IN CALVES

In this paper, anatomopathologic lesions of 12 calves with induced pol ioencephalomalacia are described. Euthanasia was performed at differen t stages of The disease which allowed us to recognize a lesion pattern characterized by initial neuronal necrosis of the gray matter of the cerebral cortex, followed by endothelial cell necrosis of the blood ca pillaries. In this hiperacute stage, a few animals showed mild infiltr ation with neutrophils. In a more advanced stage of the disease, regen eration of the endothelial cells was prominent but with necrosis of th e glial cells with infiltration of macrophages in the perivascular spa ces. The latter condition was characterized by cavitation of the cereb ral cortex. The use of UV light was useful to recognize different patt erns of light was useful to recognize different patterns of autofluore scence that help in the gross diagnosis of the disease. The hiperacute presentation (sudden death with cerebral oedema) showed small fluores cent areas, but those calves that carried the disease for 2-3 days sho wed extensive autofluorescence areas. In the more advanced condition, fluorescence almost disappeared as a consequence of the extensive cavi tation of the cortex.