Bovine Pestivirus heterogeneity is a major challenge for vaccines against bovine viral diarrhea (BVD). In breeding herds, fetal protection is a high priority issue. To some degree, fetal infections in vaccinated heifers have been attributed to the antigenic diversity of bovine Pestiviruses. The purpose of this study was to assess fetal protection against a divergent bovine Pestivirus (Hobi-like Pestivirus, HoBiPeV) with a commercially available modified live vaccine (MLV) claiming fetal protection against BVDV 1 and BVDV 2 up to one year after the first inoculation. Five vaccinated and four unvaccinated heifers were challenged by intranasal inoculation with the HoBiPeV Italy-1/10-1 strain between 82 and 89 days after insemination, i.e. between 4 and 6 months after vaccination. At challenge, neutralizing antibody titers to HoBiPeV in vaccinated heifers were low or even undetectable. Of the four unvaccinated heifers, one control animal aborted (fetus not available) and the remaining three gave birth to HoBiPeV positive calves. Among the heifers of the vaccinated group, one aborted the fetus in the sixth month of pregnancy, which tested Pestivirus negative, while three others gave birth to healthy, HoBiPeV negative calves; the remaining heifer delivered one HoBiPeV positive calf. The results suggest that the BVDV vaccine might be able to elicit a partial fetal protection against HobiPeV, even in absence of a strong specific antibody response.

牛瘟病毒异质性是牛病毒性腹泻 (BVD) 疫苗的主要挑战。在种猪群中，胎儿保护是一个高度优先的问题。在某种程度上，接种疫苗的小母牛的胎儿感染归因于牛瘟病毒的抗原多样性。本研究的目的是评估胎儿对不同牛瘟病毒（Hobi-like Pestivirus，HoBiPeV）的保护作用，使用市售的改良活疫苗 (MLV)，声称对 BVDV 1 和 BVDV 2 的胎儿保护作用在第一次接种后长达一年. 在授精后82至89天之间，即在接种后4至6个月之间，通过鼻内接种HoBiPeV Italy-1/10-1菌株来攻击五头接种疫苗和四头未接种疫苗的小母牛。在挑战中，在接种过疫苗的小母牛中，HoBiPeV 的中和抗体滴度很低，甚至检测不到。在四头未接种疫苗的小母牛中，一头对照动物流产（胎儿不可用），其余三头产下 HoBiPeV 阳性小牛。接种组的小母牛中，一头在怀孕第 6 个月时流产，经检测瘟病毒呈阴性，另外三头产下健康的 HoBiPeV 阴性小牛；剩下的小母牛产下了一只 HoBiPeV 阳性小牛。结果表明，即使没有强烈的特异性抗体反应，BVDV 疫苗也可能引起对 HobiPeV 的部分胎儿保护。接种组的小母牛中，一头在怀孕第 6 个月时流产，经检测瘟病毒呈阴性，另外三头产下健康的 HoBiPeV 阴性小牛；剩下的小母牛产下了一只 HoBiPeV 阳性小牛。结果表明，即使没有强烈的特异性抗体反应，BVDV 疫苗也可能引起对 HobiPeV 的部分胎儿保护。接种组的小母牛中，一头在怀孕第 6 个月时流产，经检测瘟病毒呈阴性，另外三头产下健康的 HoBiPeV 阴性小牛；剩下的小母牛产下了一只 HoBiPeV 阳性小牛。结果表明，即使没有强烈的特异性抗体反应，BVDV 疫苗也可能引起对 HobiPeV 的部分胎儿保护。