Introduction

The objective of this study is to show the importance of interspecies links and temporal network dynamics of a multi-species livestock movement network. Although both cattle and sheep networks have been previously studied, cattle-sheep multi-species networks have not generally been studied in-depth. The central question of this study is how the combination of cattle and sheep movements affects the potential for disease spread on the combined network.

Materials and methods

Our analysis considers static and temporal representations of networks based on recorded animal movements. We computed network-based node importance measures of two single-species networks, and compared the top-ranked premises with the ones in the multi-species network. We propose the use of a measure based on contact chains calculated in a network weighted with transmission probabilities to assess the importance of premises in an outbreak. To ground our investigation in infectious disease epidemiology, we compared this suggested measure with the results of disease simulation models with asymmetric probabilities of transmission between species.

Results

Our analysis of the temporal networks shows that the premises which are likely to drive the epidemic in this multi-species network differ from the ones in both the cattle and the sheep networks. Although sheep movements are highly seasonal, the estimated size of an epidemic is significantly larger in the multi-species network than in the cattle network, independently of the period of the year. Finally, we demonstrate that a measure based on contact chains allow us to identify around 30% of the key farms in a simulated epidemic, ignoring markets, whilst static network measures identify less than 10% of these farms.

Conclusion

Our results ascertain the importance of combining species networks, as well as considering layers of temporal livestock movements in detail for the study of disease spread.

中文翻译：

---

牲畜运动的多物种时间网络，用于疾病传播

介绍

这项研究的目的是表明种间链接和多物种牲畜移动网络的时间网络动态的重要性。尽管先前已经对牛和绵羊网络进行了研究，但是对牛-绵羊多物种网络的研究尚未普遍深入。这项研究的中心问题是牛和羊运动的组合如何影响组合网络上疾病传播的可能性。

材料和方法

我们的分析考虑了基于记录的动物运动的网络的静态和时间表示。我们计算了两个单物种网络的基于网络的节点重要性度量，并将排名最高的前提与多物种网络中的前提进行了比较。我们建议使用基于在具有传输概率加权的网络中计算的接触链的度量来评估疫情在场所中的重要性。为了使我们在传染病流行病学方面的研究立足于基础，我们将该建议措施与具有物种间传播不对称概率的疾病模拟模型的结果进行了比较。

结果

我们对时间网络的分析表明，在这个多物种网络中可能导致流行的前提不同于牛和羊网络中的前提。尽管绵羊的活动是高度季节性的，但与一年中的时期无关，在多物种网络中估计的疫情规模要比在牛网络中的疫情规模大得多。最后，我们证明了基于接触链的度量可以使我们在模拟流行病中识别大约30％的关键农场，而忽略市场，而静态网络度量仅识别不到这些农场的10％。

结论

我们的结果确定了结合物种网络的重要性，并详细考虑了牲畜的暂时性运动层次，以研究疾病的传播。