Pathogenetic Studies of Infection of the Bovine Fetus with Bovine Viral Diarrhea Virus I. Cerebellar Atrophy

A cytopathogenic strain of bovine viral diarrhea virus was intravenously inoculated into 14 pregnant susceptible and two control heifers at 150 ± 1 days of gestation. Fetuses were surgically taken at sequential steps after inoculation. Acute cerebellar lesions consisting of leptomeningeal inflammation, necrosis of cells in the external germinal layer, focal hemorrhages and moderate to severe folial edema were seen in the fetuses taken at 17 and 21 days after inoculation. By 42 days, the cerebellar lesion had completely evolved, and the inflammatory reaction was subsiding. Moderate to severe folial degeneration with cavitation characterized the residual cerebellar lesion. Folial edema caused the major destruction of cerebellar tissue. Necrosis of cortical neurons and focal hemorrhages also contributed to the residual lesion.