Intervet/Schering-Plough Animal Health, 35500W. 91st Street, De Soto, KS 66018, USA.
Vaccine. 2011 Jun 24;29(29-30):4657-62. doi: 10.1016/j.vaccine.2011.04.129. Epub 2011 May 17.
Recent studies showed that BVDV-1b subgenotype is dominant in North and South American field BVDV isolates. However, nearly all commercially available BVDV-1 vaccines contain BVDV-1a strains. In order to study the efficacy of BVDV-1a vaccine against BVDV-1b infection, this study was designed to evaluate a modified-live vaccine (MLV) containing BVDV-1a and BVDV-2 strains for its efficacy in prevention of persistent infection of fetuses against BVDV-1b strain, when the heifers were vaccinated prior to breeding. Heifers were vaccinated subcutaneously with a single dose of the MLV and bred four weeks after vaccination. The pregnant heifers were challenged with a non-cytopathic BVDV-1b strain at approximately 80 days of gestation. Vaccinated heifers were protected from clinical disease and viremia caused by the BVDV-1b virus. At approximately 155 days of gestation, the fetuses were harvested and tissue samples of thymus, lungs, spleen, kidney and intestines were collected for virus isolation. BVDV was isolated from 100% of the fetuses in the non-vaccinated control group, and from only one fetus (4.3%) from the vaccinated group. Results demonstrated that the MLV containing BVDV-1a and BVDV-2 strains provided 96% protection from fetal persistent infection caused by the BVDV-1b strain.
最近的研究表明，BVDV-1b 亚群在美国北部和南部的田间 BVDV 分离株中占主导地位。然而，几乎所有市售的 BVDV-1 疫苗都含有 BVDV-1a 株。为了研究 BVDV-1a 疫苗对 BVDV-1b 感染的效力，本研究旨在评估一种含有 BVDV-1a 和 BVDV-2 株的改良活疫苗（MLV）对预防胎儿持续性感染 BVDV-1b 株的效果，当后备牛在配种前接种疫苗时。后备牛皮下接种一剂 MLV，接种后四周配种。怀孕的后备牛在妊娠约 80 天时用非细胞病变性 BVDV-1b 株进行攻毒。接种疫苗的后备牛免受 BVDV-1b 病毒引起的临床疾病和病毒血症的影响。在妊娠约 155 天时，收获胎儿，采集胸腺、肺、脾、肾和肠组织样本进行病毒分离。未接种疫苗的对照组 100%的胎儿中分离到 BVDV，而接种组中只有 1 只胎儿（4.3%）分离到 BVDV。结果表明，含有 BVDV-1a 和 BVDV-2 株的 MLV 对由 BVDV-1b 株引起的胎儿持续性感染提供了 96%的保护。
