Effect of bovine herpes virus-1, bluetongue virus and akabane virus on the in vitro development of bovine embryos.

Bovine oocytes enclosed by follicular epithelial (FE) cells were exposed to bovine herpes virus-1 (BHV-1), bluetongue virus (BTV) and akabane virus (AV), matured in culture for 24 h and then in vitro fertilized. In the BHV-1-exposed group, BHV-1 was isolated from medium 3 days after in vitro fertilization at a high titer, and a severe cytopathic effect was observed in the FE cells. Oocytes in the BHV-1-exposed group developed to the 2-cell to 8-cell stage, but failed to develop into blastocysts. In the BTV-exposed group, BTV replication was observed in the FE cells during in vitro embryo development into blastocysts. In the AV-exposed group, no distinct AV replication was detected in FE cells during in vitro embryo development. These results indicate that these viruses failed to infect zona-intact oocytes or embryos during in vitro maturation and culture.