Watts E J, Palmer S C F, Bowman A S, Irvine R J, Smith A, Travis J M J
Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
Parasitology. 2009 Sep;136(10):1221-34. doi: 10.1017/S0031182009990424. Epub 2009 Jul 27.
Many vector-borne pathogens whose primary vectors are generalists, such as Ixodid ticks, can infect a wide range of host species and are often zoonotic. Understanding their transmission dynamics is important for the development of disease management programmes. Models exist to describe the transmission dynamics of such diseases, but are necessarily simplistic and generally limited by knowledge of vector population dynamics. They are typically deterministic SIR-type models, which predict disease dynamics in a single, non-spatial, closed patch. Here we explore the limitations of such a model of louping-ill virus dynamics by challenging it with novel field data. The model was only partially successful in predicting Ixodes ricinus density and louping-ill virus prevalence at 6 Scottish sites. We extend the existing multi-host model by forming a two-patch model, incorporating the impact of roaming hosts. This demonstrates that host movement may account for some of the discrepancies between the original model and empirical data. We conclude that insights into the dynamics of multi-host vector-borne pathogens can be gained by using a simple two-patch model. Potential improvements to the model, incorporating aspects of spatial and temporal heterogeneity, are outlined.
许多以硬蜱等泛化性媒介为主要传播媒介的病媒传播病原体，能够感染多种宿主物种，且往往具有人畜共患病性质。了解它们的传播动态对于制定疾病管理计划很重要。现有模型用于描述此类疾病的传播动态，但必然较为简单，通常受限于对媒介种群动态的了解。它们通常是确定性的SIR型模型，可预测单一、非空间、封闭区域内的疾病动态。在此，我们通过用新的实地数据对其进行验证，探讨这样一个跳跃病病毒动态模型的局限性。该模型在预测6个苏格兰地点的蓖麻硬蜱密度和跳跃病病毒流行率方面仅取得部分成功。我们通过构建一个双区域模型，纳入游荡宿主的影响，对现有的多宿主模型进行扩展。这表明宿主移动可能是原模型与实证数据之间某些差异的原因。我们得出结论，使用一个简单的双区域模型能够深入了解多宿主病媒传播病原体的动态。文中概述了该模型在纳入空间和时间异质性方面的潜在改进方向。
