Graduate School of Agriculture and Life Science, The University of Tokyo, Tokyo, Japan.
Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
Transbound Emerg Dis. 2018 Feb;65(1):e135-e144. doi: 10.1111/tbed.12693. Epub 2017 Aug 14.
Bovine viral diarrhoea virus (BVDV) infection in cattle can result in growth retardation, reduced milk production, reproductive disorders and death. Persistently infected animals are the primary source of infection. In Hokkaido, Japan, all cattle entering shared pastures in summer are vaccinated before movement for disease control. Additionally, these cattle may be tested for BVDV and culled if positive. However, the effectiveness of this control strategy aiming to reduce the number of BVDV-infected animals has not been assessed. The aim of this study was to evaluate the effectiveness of various test-and-cull and/or vaccination strategies on BVDV control in dairy farms in two districts of Hokkaido, Nemuro and Hiyama. A stochastic model was developed to compare the different control strategies over a 10-year period. The model was individual-based and simulated disease dynamics both within and between herds. Parameters included in the model were obtained from the literature, the Hokkaido government and the Japanese Ministry of Agriculture, Forestry and Fisheries. Nine different scenarios were compared as follows: no control, test-and-cull strategies based on antigen testing of either calves or only cattle entering common pastures, vaccination of all adult cattle or only cattle entering shared pastures and combinations thereof. The results indicate that current strategies for BVDV control in Hokkaido slightly reduced the number of BVDV-infected animals; however, alternative strategies such as testing all calves and culling any positives or vaccinating all susceptible adult animals dramatically reduced those. To our knowledge, this is the first report regarding the comparison of the effectiveness between the current strategies in Hokkaido and the alternative strategies for BVDV control measures.
牛病毒性腹泻病毒（BVDV）感染牛可导致生长迟缓、产奶量减少、繁殖障碍和死亡。持续性感染动物是主要的感染源。在日本北海道，所有进入夏季共享牧场的牛在移动前都要接种疫苗以控制疾病。此外，如果 BVDV 检测呈阳性，这些牛可能会被淘汰。然而，这种旨在减少 BVDV 感染动物数量的控制策略的有效性尚未得到评估。本研究旨在评估不同的检测和淘汰以及/或疫苗接种策略在北海道两个地区（根室和日高山）的奶牛场对 BVDV 控制的效果。建立了一个随机模型来比较不同的控制策略在 10 年内的效果。该模型是基于个体的，模拟了畜群内和畜群间的疾病动态。模型中使用的参数来自文献、北海道政府和日本农林水产省。比较了以下 9 种不同情况：不进行控制、基于抗原检测小牛或仅进入共同牧场的牛的检测和淘汰策略、对所有成年牛或仅进入共享牧场的牛进行疫苗接种以及它们的组合。结果表明，目前北海道的 BVDV 控制策略略微减少了 BVDV 感染动物的数量；然而，替代策略，如检测所有小牛并淘汰任何阳性动物，或接种所有易感成年动物，则大大减少了感染动物的数量。据我们所知，这是首次比较北海道现行策略与替代 BVDV 控制措施的有效性的报告。
