University of Helsinki, Department of Biosciences, Helsinki, FI-00014, Finland.
Sci Rep. 2017 Aug 10;7(1):7729. doi: 10.1038/s41598-017-07983-2.
The epidemiological dynamics of potentially free-living pathogens are often studied with respect to a specific pathogen species (e.g., cholera) and most studies concentrate only on host-pathogen interactions. Here we show that metacommunity-level interactions can alter conventional spatial disease dynamics. We introduce a pathogen eating consumer species and investigate a deterministic epidemiological model of two habitat patches, where both patches can be occupied by hosts, pathogens, and consumers of free-living pathogens. An isolated habitat patch shows periodic disease outbreaks in the host population, arising from cyclic consumer-pathogen dynamics. On the other hand, consumer dispersal between the patches generate asymmetric disease prevalence, such that the host population in one patch stays disease-free, while disease outbreaks occur in the other patch. Such asymmetry can also arise with host dispersal, where infected hosts carry pathogens to the other patch. This indirect movement of pathogens causes also a counter-intuitive effect: decreasing morbidity in a focal patch under increasing pathogen immigration. Our results underline that community-level interactions influence disease dynamics and consistent spatial asymmetry can arise also in spatially homogeneous systems.
具有潜在自由生活能力的病原体的流行病学动态通常是针对特定病原体物种（例如霍乱）进行研究的，并且大多数研究仅集中于宿主-病原体相互作用。在这里，我们表明，后生动物群落水平的相互作用可以改变传统的空间疾病动态。我们引入了一种以病原体为食的消费者物种，并研究了两个栖息地斑块的确定性流行病学模型，其中两个斑块都可以被宿主、病原体和自由生活病原体的消费者占据。孤立的栖息地斑块显示宿主种群中周期性的疾病爆发，这是由于消费者-病原体的循环动态引起的。另一方面，消费者在斑块之间的扩散会产生不对称的疾病流行，使得一个斑块中的宿主种群保持无病状态，而另一个斑块中则发生疾病爆发。这种不对称性也可能因宿主扩散而产生，其中感染的宿主将病原体带到另一个斑块。这种病原体的间接传播还会产生一种反直觉的效果：在病原体移民增加的情况下，焦点斑块的发病率降低。我们的研究结果强调了群落水平的相互作用会影响疾病动态，并且在空间均匀的系统中也可能出现一致的空间不对称性。
