Abstract
In October 2001, a 9-year-old Japanese Black cow demonstrating such neurological abnormalities as clonic convulsion, torticollis, and blindness was subjected to pathological, biochemical, and pathogenic examinations 6 days after the emergence of the condition. Macroscopically, several yellowish lesions were observed in the cerebral cortex. Histological examination demonstrated focal or laminar areas of necrosis distributed through the cerebral cortex, neuropil vacuolation at the dorsal vagus nuclei in the medulla oblongata, and nephrosis with acid-fast intranuclear inclusions. On a dry-weight basis, the lead content of the liver was 51.2 ppm and that of the renal cortex 122.3 ppm. ELISA, Western blotting, and immunohistochemical techniques detected no abnormal prion-protein isoform from the obex region of the medulla oblongata. These findings suggest that the cow was affected by lead poisoning and that the changes in the medulla oblongata were associated with this poisoning and not with bovine spongiform encephalopathy. A fishing-net rope containing lead wire that had been used to retain the cow was suspected to be the source of the lead
