Chang You, Widgren Stefan, de Jong Mart C M, Tratalos Jamie A, More Simon J, Hartemink Nienke
Quantitative Veterinary Epidemiology group, Wageningen University and Research Centre, the Netherlands.
Department of Disease Control and Epidemiology, National Veterinary Institute, Uppsala 751 89, Sweden.
Prev Vet Med. 2025 Feb;235:106386. doi: 10.1016/j.prevetmed.2024.106386. Epub 2024 Nov 28.
Bovine tuberculosis (bTB) has a complex infection ecology and is difficult to control in many countries, including Ireland. For many years, the Irish national bTB eradication programme relied on cattle-based control measures, including test-and-removal with related movement restrictions. In the early 2000s, badger culling was added as a part of the control measure in the national programme. As badgers are protected animals under Wildlife Acts, making culling undesirable, this practice is now progressively being replaced by badger vaccination. However, it is unclear whether badger vaccination, in combination with the cattle test-and-removal and movement restriction, is sufficient to eradicate bTB, or whether additional measures will be needed. Assessing the impact of badger vaccination on reducing bTB in cattle is complex due to the involvement of multiple hosts and transmission routes. Key contributors include transmission to and from wildlife (e.g., European badger, Meles meles), the persistence of Mycobacterium bovis in the environment, and - due to imperfect diagnostic tests - the movement of infected cattle and residual infection in the herd. Understanding of relative contribution of these infectious sources is a key knowledge gap. This study aims to assess the impact of badger vaccination, in addition to cattle test-and-removal and movement restriction, on bTB eradication at a regional level and to assess whether additional interventions are needed. Additionally, we investigate the contribution of several transmission mechanisms such as, local cattle, residual infection, badgers and introduced cattle on the transmission of bTB at the level of both the individual and the herd. To achieve this, we developed a metapopulation model that includes each of the above-mentioned transmission mechanisms for the Kilkenny badger vaccination trial area. The model incorporates within-herd transmission for cattle and within-territory transmission for badgers, and also transmission between herds, both via cattle trade movements and via overlapping badger territories. Our results show that cattle-to-cattle transmission contributes most to new cattle infections at the individual animal (cattle) level, while breakdowns at the herd level usually involve multiple routes. Badger vaccination, when combined with cattle test-and-removal programme, may not be sufficient to achieve eradication in this region. We highlight the need for additional interventions that target cattle, badger, and movement to form a comprehensive intervention strategy, including cattle vaccination, improve farm biosecurity, badger vaccination and risk-based trading.
牛结核病（bTB）具有复杂的感染生态，在包括爱尔兰在内的许多国家都难以控制。多年来，爱尔兰国家牛结核病根除计划依赖于以牛为基础的控制措施，包括检测并清除以及相关的移动限制。在21世纪初，獾捕杀被作为国家计划控制措施的一部分加入进来。由于獾是《野生动物法》保护的动物，捕杀并不理想，这种做法现在正逐渐被獾疫苗接种所取代。然而，尚不清楚獾疫苗接种与牛的检测清除及移动限制相结合是否足以根除牛结核病，或者是否需要额外的措施。由于涉及多个宿主和传播途径，评估獾疫苗接种对减少牛群中牛结核病的影响很复杂。关键因素包括与野生动物（如欧洲獾，鼬獾）之间的传播、牛分枝杆菌在环境中的持久性，以及由于诊断测试不完善导致的感染牛的移动和牛群中的残留感染。了解这些传染源的相对贡献是一个关键的知识空白。本研究旨在评估除牛的检测清除和移动限制外，獾疫苗接种对区域层面牛结核病根除的影响，并评估是否需要额外的干预措施。此外，我们调查了几种传播机制，如本地牛、残留感染、獾和引入牛在个体和牛群层面上对牛结核病传播的贡献。为实现这一目标，我们开发了一个集合种群模型，该模型包括基尔肯尼獾疫苗接种试验区上述每种传播机制。该模型纳入了牛群内牛的传播和獾领地内獾的传播，以及通过牛的贸易流动和重叠的獾领地在牛群之间的传播。我们的结果表明，在个体动物（牛）层面，牛与牛之间的传播对新的牛感染贡献最大，而牛群层面的疫情爆发通常涉及多种途径。獾疫苗接种与牛的检测清除计划相结合，可能不足以在该地区实现根除。我们强调需要针对牛、獾和移动的额外干预措施，以形成一个全面的干预策略，包括牛疫苗接种、改善农场生物安全、獾疫苗接种和基于风险的交易。
