Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2012
Publication Date: 7/1/2012
Citation: Ridpath, J.F., Neill, J.D., Chase, C.C. 2012. Impact of BVDV infection of white-tailed deer during second and third trimesters of pregnancy. Journal of Wildlife Diseases. 48(3):758-762. Interpretive Summary: Infections with bovine viral diarrhea viruses (BVDV) result in considerable economic loss to dairy and beef producers. BVDV infections, in pregnant cattle, are particularly problematic. The outcome of such infections is dependent on the developmental stage of the fetus. Infection of cattle in the first one third of gestation (first trimester) can result in the death of the fetus and/or a number of different birth defects. Infection in the second one third of gestation (second trimester) may result in fetal death but at a lower rate than in first trimester infections. Infection in the final one third of gestation (third trimester) does not cause many problems. Previous research demonstrated that the outcome of infection of white-tailed deer in the first trimester is very similar to cattle. This study was done to determine if infection of deer with BVDV in the second and third trimesters also resulted in outcomes that were similar to cattle. Infection of deer in the second trimester resulted in death in about half of the fetuses. Unlike cattle, the deer were more likely to just reabsorb the dead fetus rather than abort and expel the fetal material. Infection of deer in the third trimester did not seem to have any effect on fetal health. These results indicate that BVDV infections result in reproductive disease in deer that is very similar to the reproductive disease observed in cattle. This suggests that similar control programs can be used for reducing BVDV infection in cattle and deer. As cattle and deer populations in the U.S. are in frequent contact it appears that it will be necessary to control BVDV in both populations in order to reduce BVDV infections in cattle.
Technical Abstract: While it has been demonstrated that persistent bovine viral diarrhea virus (BVDV) infections can be established in white-tailed deer following in utero exposure in the first trimester of gestation, there is little to no information regarding the outcome of infection, in deer, in later stages of pregnancy. The goal of this study was to observe the impact of infection of white-tailed deer in the second and third trimesters of pregnancy. Six white-tailed deer in the second trimester of pregnancy and four in the third trimester were infected with BVDV type 2 virus previously isolated from a persistently infected deer harvested from the wild. Infection of deer in the second trimester of pregnancy resulted in reproductive failure in four out of six deer. Fawns born to the two remaining deer appeared normal and were born with titers against BVDV. Infection of does in the third trimester of pregnancy did not result in reproductive failure as all does gave birth to live, healthy fawns. These fawns were also born with antibodies against BVDV. These results, combined with those previously reported regarding BVDV infection in the first trimester of pregnancy, suggest that the impact of BVDV infection of pregnant white-tailed deer is very similar to that observed in pregnant cattle.