Heterogeneously structured compartmental models of epidemiological systems: from individual-level processes to population-scale dynamics

Fuente: arXiv
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Auteurs principaux: Bernardi, Emanuele, Lorenzi, Tommaso, Sensi, Mattia, Tosin, Andrea
Format: Preprint
Publié: 2025
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author Bernardi, Emanuele
Lorenzi, Tommaso
Sensi, Mattia
Tosin, Andrea
author_facet Bernardi, Emanuele
Lorenzi, Tommaso
Sensi, Mattia
Tosin, Andrea
contents We develop a general modelling framework for compartmental epidemiological systems structured by continuous variables which are linked to the levels of expression of compartment-specific traits. We start by formulating an individual-based model that describes the dynamics of single individuals in terms of stochastic processes. Then we formally derive: (i) the mesoscopic counterpart of this model, which is formulated as a system of integro-differential equations for the distributions of individuals over the structuring-variable domains of the different compartments; (ii) the corresponding macroscopic model, which takes the form of a system of ordinary differential equations for the fractions of individuals in the different compartments and the mean levels of expression of the traits represented by the structuring variables. We employ a reduced version of the macroscopic model to obtain a general formula for the basic reproduction number, $\mathcal{R}_0$, in terms of key parameters and functions of the underlying microscopic model, so as to illustrate how such a modelling framework makes it possible to draw connections between fundamental individual-level processes and population-scale dynamics. Finally we apply the modelling framework to case studies based on classical compartmental epidemiological systems, for each of which we report on Monte Carlo simulations of the individual-based model as well as on analytical results and numerical solutions of the macroscopic model.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11225
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Heterogeneously structured compartmental models of epidemiological systems: from individual-level processes to population-scale dynamics
Bernardi, Emanuele
Lorenzi, Tommaso
Sensi, Mattia
Tosin, Andrea
Populations and Evolution
Dynamical Systems
We develop a general modelling framework for compartmental epidemiological systems structured by continuous variables which are linked to the levels of expression of compartment-specific traits. We start by formulating an individual-based model that describes the dynamics of single individuals in terms of stochastic processes. Then we formally derive: (i) the mesoscopic counterpart of this model, which is formulated as a system of integro-differential equations for the distributions of individuals over the structuring-variable domains of the different compartments; (ii) the corresponding macroscopic model, which takes the form of a system of ordinary differential equations for the fractions of individuals in the different compartments and the mean levels of expression of the traits represented by the structuring variables. We employ a reduced version of the macroscopic model to obtain a general formula for the basic reproduction number, $\mathcal{R}_0$, in terms of key parameters and functions of the underlying microscopic model, so as to illustrate how such a modelling framework makes it possible to draw connections between fundamental individual-level processes and population-scale dynamics. Finally we apply the modelling framework to case studies based on classical compartmental epidemiological systems, for each of which we report on Monte Carlo simulations of the individual-based model as well as on analytical results and numerical solutions of the macroscopic model.
title Heterogeneously structured compartmental models of epidemiological systems: from individual-level processes to population-scale dynamics
topic Populations and Evolution
Dynamical Systems
url https://arxiv.org/abs/2503.11225