Abstract
Two newborn calves with congenital malformations were subjected to the epizootiological, pathological, and serological examinations. They showed ataxia and blindness. At autopsy, cerebellar hypoplasia and reduction in size of the optic nerves were observed in both cases, in addition to severe hydrocephalus in one case. Microscopically, diminution and irregular arrangement of granular and Purkinje cells, heterotopia of Purkinje cells in the cortex, and cavitation in the medullary plates of the cerebellum were all observed. The rod and cone cells in the outer nuclear layer of the retina and nerve fibers in the optic nerves were notably decreased in number. Neutralizing antibody against bovine viral diarrhea-mucosal disease (BVD-MD) virus was demonstrated in the postcolostrous sera of both cases. An epizootiological survey revealed that the dam of one case might have become infected with the virus on a public pasture where the animal had been grazed during a period from the 3rd to the 8th month of gestation, and the other dam suffered from temporary diarrhea at the 5th month of gestation, suggesting infection with BVD-MD virus. Based on the data collected, the present cases were diagnosed as BVD-MD caused by intrauterine infection.
