From the Bernoulli Institute for Mathematics, Computer Science and Artificial Intelligence, University of Groningen, the Netherlands.
Department of Statistics, Informatics and Modelling, National Institute for Public Health and the Environment, Bilthoven, Netherlands.
Epidemiology. 2020 May;31(3):327-333. doi: 10.1097/EDE.0000000000001169.
Food-borne disease outbreaks constitute a large health burden on society. One of the challenges when investigating such outbreaks is to trace the origin of the outbreak. In this study, we consider a network model to determine the spatial origin of the contaminated food product that caused the outbreak.
The network model we use replaces the classic geographic distance of a network by an effective distance so that two nodes connected by a long-range link may be more strongly connected than their geographic distance would suggest. Furthermore, the effective distance transforms complex spatial patterns into regular topological patterns, creating a means for easier identification of the origin of the spreading phenomenon. Because detailed information on food distribution is generally not available, the model uses the gravity model from economics: the flow of goods from one node to another increases with population size and decreases with the geographical distance between them.
This effective distance network approach has been shown to perform well in a large Escherichia coli O104:H4 outbreak in Germany in 2011. In this article, we apply the same method to various food-borne disease outbreaks in the Netherlands. We found the effective distance network approach to fail in certain scenarios.
Great care should be taken as to whether the underlying network model correctly captures the spreading mechanism of the outbreak in terms of spatial scale and single or multiple source outbreak.
食源性疾病暴发对社会造成了巨大的健康负担。在调查此类暴发时，面临的挑战之一是追踪暴发的源头。在本研究中，我们考虑使用网络模型来确定引发暴发的污染食品的空间来源。
我们使用的网络模型用有效距离替代经典网络中的地理距离，使得通过远程链路连接的两个节点可能比它们的地理距离所暗示的连接更紧密。此外，有效距离将复杂的空间模式转换为规则的拓扑模式，为更容易识别传播现象的起源提供了一种手段。由于通常无法获得有关食品分布的详细信息，因此该模型使用经济学中的重力模型：货物从一个节点流向另一个节点的流量随节点的人口规模增加而增加，随它们之间的地理距离增加而减少。
在 2011 年德国发生的一次大规模大肠杆菌 O104：H4 暴发中，这种有效距离网络方法已被证明效果良好。在本文中，我们将相同的方法应用于荷兰的各种食源性疾病暴发。我们发现，在某些情况下，有效距离网络方法会失败。
应特别注意底层网络模型是否正确捕捉暴发的空间尺度和单源或多源暴发的传播机制。
