Vaccination against bovine viral diarrhea (BVD) is one of the key elements to protect cattle herds from this economically important disorder. Bovine viral diarrhea virus (BVDV) is a pestivirus infecting animals at all ages with significant impact on reproductive, digestive, and respiratory systems. Financial burden caused by this pathogen prompts many farmers to introduce vaccination as the control and prophylactic measure especially when persistently infected (PI) individuals, being the main source of the virus in the herd, are removed after test-and-cull approach. The aim of this study was to analyze serological response in cattle herds where without or despite the removal of PI animals and the introduction of the whole herd vaccination, new PI calves were identified. Overall seroprevalence in 5 vaccinated herds was 91.7% and 83.3% using ELISA and virus neutralization test, respectively. Despite high titers for both vaccine and field strains of BVDV in analyzed herds the analysis of comparative strength of neutralization indicated that 41.4% of positive samples did not have a predominant titer against one specific subtype of BVDV. In 3 herds BVDV-1b subtype was identified while in 2 others it was BVDV-1d while the vaccine used was based on BVDV-1a which was never identified in Poland so far.

中文翻译：

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牛病毒性腹泻感染的根除和控制计划中的疫苗接种失败

预防牛病毒性腹泻（BVD）的疫苗接种是保护牛群免受这种具有经济意义的疾病的关键因素之一。牛病毒性腹泻病毒（BVDV）是一种瘟病毒，可感染各个年龄段的动物，对生殖，消化和呼吸系统具有重大影响。由这种病原体引起的经济负担促使许多农民采用疫苗接种作为控制和预防措施，尤其是在经过反复试验后去除了作为感染牛群病毒主要来源的持续感染的个体之后。这项研究的目的是分析牛群中的血清学反应，在没有或没有去除PI动物和引入整个牛群疫苗的情况下，已鉴定出新的PI犊牛。5个接种牛群的总体血清阳性率分别为91.7％和83。使用ELISA和病毒中和测试分别占3％。尽管在分析的猪群中BVDV的疫苗和野毒株的滴度都很高，但中和比较强度的分析表明，41.4％的阳性样品对BVDV的一种特定亚型没有主要的滴度。在3个牛群中鉴定出BVDV-1b亚型，而在另外2个牛群中鉴定出BVDV-1d，而所用疫苗基于BVDV-1a，到目前为止在波兰尚未发现。