Zabel Taylor A, Agusto Folashade B
Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA.
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.
Interdiscip Perspect Infect Dis. 2018 May 2;2018:4373981. doi: 10.1155/2018/4373981. eCollection 2018.
Bovine anaplasmosis is an infectious disease of cattle caused by the obligate intercellular bacterium, , and it primarily occurs in tropical and subtropical regions of the world. In this study, an age-structured deterministic model for the transmission dynamics of bovine anaplasmosis was developed; the model incorporates symptomatic and asymptomatic cattle classes. Sensitivity analysis was carried out to determine the parameters with the highest impact on the reproduction number. The dominant parameters were the bovine natural and disease-induced death rates, disease progression rate in adult cattle, the mechanical devices transmission probability and contact rates, the pathogen contamination, and decay rates on the mechanical devices. The result of the sensitivity analysis suggests that control strategies to effectively prevent/control the spread of bovine anaplasmosis should focus on these parameters according to their positive or negative effect as seen from the sensitivity index. Following the results of the sensitivity analysis, three control strategies were investigated, namely, bovine-culling, safety-control, and universal. In addition to these strategies, three effectiveness levels (low, medium, and high) were considered for each control strategy using the cumulative number of newly infected cases in both juvenile and adult cattle as measure function. The universal strategy (comprising both cattle-culling and safety-control strategies) is only marginally better at reducing the number of infected cattle compare to the safety-control strategy. This result suggests that efforts should be aimed at improving and maintaining good hygiene practices; furthermore, the added benefit of culling infected cows is only minimal and not cost-efficient.
牛无形体病是由专性细胞内细菌引起的牛的一种传染病，主要发生在世界热带和亚热带地区。在本研究中，建立了一个用于牛无形体病传播动力学的年龄结构确定性模型；该模型纳入了有症状和无症状的牛群类别。进行了敏感性分析以确定对繁殖数影响最大的参数。主要参数包括牛的自然死亡率和疾病诱导死亡率、成年牛的疾病进展率、机械传播概率和接触率、病原体在机械装置上的污染和衰减率。敏感性分析结果表明，根据敏感性指数中所见的正负效应，有效预防/控制牛无形体病传播的控制策略应关注这些参数。根据敏感性分析结果，研究了三种控制策略，即扑杀牛、安全控制和通用策略。除了这些策略外，使用幼年和成年牛中新感染病例的累计数量作为衡量函数，为每种控制策略考虑了三个有效性水平（低、中、高）。与安全控制策略相比，通用策略（包括扑杀牛和安全控制策略）在减少感染牛数量方面仅略好一些。这一结果表明，应致力于改善和保持良好的卫生习惯；此外，扑杀感染奶牛的额外益处微乎其微且不具有成本效益。
