Marguta Ramona, Parisi Andrea
Centro de Física da Matéria Condensada, Biosystems and Integrative Sciences Institute and Departamento de Física, Faculdade de Ciências da Universidade de Lisboa, Campo Grande Edificio C8, 1749-016 Lisboa, Portugal.
Centro de Física da Matéria Condensada, Biosystems and Integrative Sciences Institute and Departamento de Física, Faculdade de Ciências da Universidade de Lisboa, Campo Grande Edificio C8, 1749-016 Lisboa, Portugal
J R Soc Interface. 2015 Mar 6;12(104):20141317. doi: 10.1098/rsif.2014.1317.
Three main mechanisms determining the dynamics of measles have been described in the literature: invasion in disease-free lands leading to import-dependent outbreaks, switching between annual and biennial attractors driven by seasonality, and amplification of stochastic fluctuations close to the endemic equilibrium. Here, we study the importance of the three mechanisms using a detailed geographical description of human mobility. We perform individual-based simulations of an SIR model using a gridded description of human settlements on top of which we implement human mobility according to the radiation model. Parallel computation permits detailed simulations of large areas. Focusing our research on the British Isles, we show that human mobility has an impact on the periodicity of measles outbreaks. Depending on the level of mobility, we observe at the global level multi-annual, annual or biennial cycles. The periodicity observed globally, however, differs from the local epidemic cycles: different locations show different mechanisms at work depending on both population size and mobility. As a result, the periodicities observed locally depend on the interplay between the local population size and human mobility.
在无疾病地区的入侵导致依赖输入的疫情爆发、由季节性驱动的年度和两年期吸引子之间的转换，以及在地方病平衡点附近随机波动的放大。在此，我们利用对人类流动的详细地理描述来研究这三种机制的重要性。我们使用人类定居点的网格化描述对SIR模型进行基于个体的模拟，并在此基础上根据辐射模型实现人类流动。并行计算允许对大面积区域进行详细模拟。我们将研究重点放在不列颠群岛，结果表明人类流动对麻疹疫情的周期性有影响。根据流动水平，我们在全球层面观察到多年、年度或两年期周期。然而，全球观察到的周期性与局部流行周期不同：不同地点根据人口规模和流动情况显示出不同的作用机制。因此，局部观察到的周期性取决于当地人口规模和人类流动之间的相互作用。
