Association of bovine embryos produced by in vitro fertilization with a noncytopathic strain of bovine viral diarrhea virus type II.

摘要

In the first of 2 experiments, 29 heifers were infected experimentally with bovine viral diarrhoea virus type II (BVDV-type II, strain CD87; characterized by high morbidity and mortality). Oocytes were recovered from these animals at slaughter 4, 8or 16 days after infection and fertilized in vitro. The infectious virus was detected in 55% of the samples of follicular fluid, 10% of the oviduct cells, 10% of the uterine flushes and 41% of the in vitro-fertilized embryos. Incidence of presence of thevirus was highest in embryos produced from oocytes recovered on day 8 (58%). The amount of the virus (101.5-2.0 TCID50/ml) associated with washed single embryos produced from oocytes recovered on days 8 and 16 was sufficient for disease transmission byintravenous inoculation to seronegative recipients (6/15). In the second experiment, uninfected oocytes recovered from BVDV-seronegative cows were exposed to BVDV (105 TCID50/ml) in the maturation medium, fertilized and cultured before viral assay. The virus was detected in 4 of 7 embryos produced from infected oocytes but not in any of the 5 embryos produced from oocytes not exposed to BVDV. The presence of BVDV in the medium did not affect embryonic development in vitro.