A clarification of transmission terms in host-microparasite models: numbers, densities and areas
A clarification of transmission terms in host-microparasite models: numbers, densities and areas
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DOI：
10.1017/s0950268802007148
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发表时间：
2002-08-01
影响因子：
4.2
通讯作者：
Turner, J
中科院分区：
文献类型：
--
作者：
Begon, M;Bennett, M;Turner, J
传播是任何传染病的动力。因此，理解疾病动力学的一个关键因素是“传播项”，它描述了易感宿主通过与感染性物质接触而“转化”为受感染宿主的速率。最近，这一术语的传统形式受到越来越多的质疑，新的术语和惯例也被提出。因此，在这里，我们回顾传输术语的推导，解释混淆的基础，并提供澄清。问题的根源在于没有明确考虑宿主种群所占据的面积，以及感染性宿主的数量和它们在种群中的密度。我们认为，术语“密度依赖传输”和“频率依赖传输”仍然有效和有用的（虽然一个“更全面”的传输术语为前者确定），但术语“质量作用”，“真正的质量作用”和“伪质量作用”都是无益的，应该删除。此外，与通常假设的相反，宿主种群中均匀和非均匀混合之间的区别与密度和频率依赖的传输模式之间的区别是正交的。
Transmission is the driving force in the dynamics of any infectious disease. A crucial element in understanding disease dynamics, therefore, is the 'transmission term' describing the rate at which susceptible hosts are 'converted' into infected hosts by their contact with infectious material. Recently, the conventional form of this term has been increasingly questioned, and new terminologies and conventions have been proposed. Here, therefore, we review the derivation of transmission terms, explain the basis of confusion, and provide clarification. The root of the problem has been a failure to include explicit consideration of the area occupied by a host population, alongside both the number of infectious hosts and their density within the population. We argue that the terms 'density-dependent transmission' and 'frequency-dependent transmission' remain valid and useful (though a 'fuller' transmission term for the former is identified), but that the terms 'mass action', 'true mass action' and 'pseudo mass action' are all unhelpful and should be dropped. Also, contrary to what has often been assumed, the distinction between homogeneous and heterogeneous mixing in a host population is orthogonal to the distinction between density- and frequency-dependent transmission modes.