Early detection surveillance for an emerging plant pathogen: a rule of thumb to predict prevalence at first discovery
Early detection surveillance for an emerging plant pathogen: a rule of thumb to predict prevalence at first discovery
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DOI：
10.1098/rspb.2015.1478
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发表时间：
2015-09-07
影响因子：
4.7
通讯作者：
van den Bosch, F.
中科院分区：
文献类型：
--
作者：
Parnell, S.;Gottwald, T. R.;van den Bosch, F.
新出现的植物病原体是保护和粮食安全的重大问题。监视通常是为了在传染病失控前发现它的入侵。然而，在实践中，许多流行病直到已经高流行时才被发现，部分原因是对监测工作与入侵流行病的动态之间的关系缺乏定量理解。我们检验了一个简单的经验法则，以确定在定期抽取固定数量样本的监测计划中，流行病在首次发现时将达到的患病率分布（发现-患病率）及其期望E（q（星号））。我们表明E（q（星号））= r / (N / Delta)，即简单地用流行病增长率除以采样率；其中r为流行病增长率，N为样本量，Delta为采样轮之间的时间。我们使用时空流行病模型以及来自真实流行病的数据证明了这一经验法则的鲁棒性。我们的工作支持这样一种观点，即为了早期检测监视的目的，简单的模型可以在明显复杂的系统中提供有用的见解。这种见解可以为植物健康监测资源分配决策提供信息，并且对入侵物种一般具有潜在的适用性。
Emerging plant pathogens are a significant problem for conservation and food security. Surveillance is often instigated in an attempt to detect an invading epidemic before it gets out of control. Yet in practice many epidemics are not discovered until already at a high prevalence, partly due to a lack of quantitative understanding of how surveillance effort and the dynamics of an invading epidemic relate. We test a simple rule of thumb to determine, for a surveillance programme taking a fixed number of samples at regular intervals, the distribution of the prevalence an epidemic will have reached on first discovery (discovery-prevalence) and its expectation E(q(star)). We show that E(q(star)) = r / (N / Delta), i.e. simply the rate of epidemic growth divided by the rate of sampling; where r is the epidemic growth rate, N is the sample size and Delta is the time between sampling rounds. We demonstrate the robustness of this rule of thumb using spatio-temporal epidemic models as well as data from real epidemics. Our work supports the view that, for the purposes of early detection surveillance, simple models can provide useful insights in apparently complex systems. The insight can inform decisions on surveillance resource allocation in plant health and has potential applicability to invasive species generally.