Pathogenetic Studies of Infection of the Bovine Fetus with Bovine Viral Diarrhea Virus

Absrrucr. Twenty-three susceptible pregnant heifers were inoculated with bovine viral diarrhea virus at 150k 1 days of gestation. Seven additional heifers were inoculated be-tween 65 and 115 days of gestation. Acute ocular lesions were seen in fetuses taken 17-21 days after inoculation of their dams at 150 days. By the fourth week, the acute lesions were beginning to resolve, and in newborn animals focal to total retinal atrophy was seen. The acute lesions were characterized by a mild to moderate retinitis that resulted in various degrees of destruction of the different layers, mononuclear cuffing of inner retinal vessels, proliferation of pigment epithelium, and choroiditis. Residually there was an absence of cellular elements in the atrophied areas of the retina, frequently a loss of layering and various numbers of pigment-containing cells. Moderately severe acute inflammation was seen in the retina of the fetus taken at 22 days after inoculation of its dam at 95 days. Ocular lesions did not occur in the other fetuses taken from heifers inoculated at earlier stages of gestation. Congenital infection of human fetuses with rubella virus and cytomegalo-virus may result in ocular lesions in addition to lesions in other tissues [14