Meningoencephalitis Tuberculosa in a Holstein Cow

The gross and histopathologic lesions of meningoencephalitis tuberculosa in a 4-year-old Holstein cow showing clinical signs compatible with bovine spongiform encephalopathy are described in this report. Grossly, numerous gray to yellow, firm and caseous nodules were seen on the ventral surfaces of the brain and in the lateral and fourth ventricles. Histopathologically, foci of caseation and dystrophic mineralization were surrounded by multinucleated giant cells, epitheloid macrophages, plasma cells, lymphocytes and fibrous proliferation. Ziehl-Neelsen stains of the lesions revealed masses of slender acid-fast bacilli in the necrotic centers of lesions and within surrounding giant cells.