Lindberg A L, Alenius S
Swedish Dairy Association, Research and Development, Uppsala, Sweden.
Vet Microbiol. 1999 Jan;64(2-3):197-222. doi: 10.1016/s0378-1135(98)00270-3.
Systematic eradication of BVDV without vaccination started in Scandinavia in 1993. In principle, the schemes include; (1) identification of non-infected and infected herds using different combinations of serological herd tests such as bulk milk tests and spot tests (sample of animals in a certain age), (2) monitoring/certification of non-infected herds by repeated sampling, applying one of the above-mentioned methods and (3) virus clearance in infected herds aimed at removing persistently infected (PI) animals in a cost- and time-efficient manner. In the virus clearance protocol described, an initial test is performed on all animals with subsequent follow-up of calves born as well as of dams seronegative in the initial test. It is generally recommended to perform an initial antibody test on all samples. This should be done not only to screen for seronegative animals on which virus isolation should be attempted (i.e. possible PI animals), but more in order to identify non-immune animals in reproductive age, that is, the key animals in herd-level persistence of infection. In Sweden, a common finding has been self-clearance, where the infection ceases without any other intervention than controlled introduction of new animals. Other epidemiological observations concern the course of events following virus introduction. Important risk factors for spreading BVDV are discussed, where livestock trade is perceived as the most central to control. Live vaccines, imported semen and embryos constitute special hazards, since they may act as vehicles for the introduction of new BVDV strains. The importance of making farmers aware of herd biosecurity and their own responsibility for it is stressed, and in order to maintain a favourable situation after a scheme has been concluded, effort must be put into establishing such a persisting attitude in the farming community.
1993年，斯堪的纳维亚半岛开始在不进行疫苗接种的情况下系统根除牛病毒性腹泻病毒（BVDV）。原则上，这些计划包括：（1）使用不同组合的血清学群体检测方法，如全乳检测和斑点检测（特定年龄动物的样本）来识别未感染和感染的畜群；（2）通过重复采样，应用上述方法之一对未感染畜群进行监测/认证；（3）在感染畜群中清除病毒，旨在以经济高效的方式清除持续感染（PI）动物。在所描述的病毒清除方案中，对所有动物进行初始检测，随后对出生的犊牛以及初始检测中血清阴性的母牛进行跟踪。通常建议对所有样本进行初始抗体检测。这样做不仅是为了筛选应尝试进行病毒分离的血清阴性动物（即可能的PI动物），更重要的是为了识别育龄期的非免疫动物，即畜群水平感染持续存在的关键动物。在瑞典，一个常见的发现是自我清除，即感染在没有任何其他干预措施（除了有控制地引入新动物）的情况下停止。其他流行病学观察涉及病毒引入后的事件进程。讨论了BVDV传播的重要风险因素，其中牲畜贸易被认为是控制的核心。活疫苗、进口精液和胚胎构成特殊危害，因为它们可能成为引入新BVDV毒株的载体。强调了让农民意识到畜群生物安全及其自身责任的重要性，并且为了在方案结束后维持有利局面，必须努力在养殖社区建立这种持续的态度。
