Response of the Bovine Fetus to Bovine Viral Diarrhea-Mucosal Disease Virus

Abstract

SUMMARY Of 26 cows in various stages of gestation (between 51 and 256 days), 24 had bovine viral diarrhea-mucosal disease ( bvd - md ) virus serum-neutralizing antibody and 2 did not have this antibody. Fetus, amniotic vesicle, or placentome of each cow was inoculated with bvd - md virus. All fetuses became infected as evidenced by lesions and isolation of bvd - md virus. Five fetuses ranging in gestational age from 51 to 99 days were aborted. Fetal death in early pregnancy and lessened severity of lesions as the gestation progressed, as well as the smaller amount of virus in the older fetuses, indicated susceptibility of the fetus to the bvd - md virus decreased as age of the fetus increased. Fetuses exposed in the 2nd and 3rd trimesters of gestational age did not die during the period of observation. Those in the 3rd trimester of gestational age had mild lesions, and fetuses 168 days or older developed serum-neutralizing antibody within 20 to 30 days after inoculations were done. The principal lesions consisted of inflammatory changes in the fetus and fetal membranes. Necrosis in lung, brain, and skin of fetuses less than 150 days of age was considered a potential cause of teratologic defects.