Neurological disorder associated with pestivirus infection in sheep in Rio Grande do Sul, Brazil

A two-month-old lamb showing signs of severe neurological disease characterized by muscular tremors, hypermetria, and motor incoordination was submitted to the Veterinary Pathology Laboratory – Universidade Federal do Rio Grande do Sul, Brazil. At necropsy, the major findings were a marked reduction of the size of the cerebellum and bilateral dilatation of the lateral ventricles. Microscopically, areas of cellular disorganization in the cerebellar cortex, reduction of the granular layer of cerebellum associated with decreased density of cells, and the presence of large cytoplasmic vacuoles in the molecular layer were observed. Neurons of the gray matter of the brain and macrophages of the mesenteric lymph nodes stained positively by the immunohistochemistry test using the monoclonal antibody 15C5 against Bovine Viral Diarrhea Virus. Taken together, those results are consistent with a pestivirus infection, or Border Disease Virus (BDV) or BVDV.