Moment approximation of infection dynamics in a population of moving hosts
Bruno Bonté1, Jean-Denis Mathias, Raphaël Duboz
1Laboratory of Engineering for Complex System (LISC) of the French National Research Institute for Science and Techniques in Environment and Agriculture (IRSTEA), Aubière, France.
Abstract:
The modelling of contact processes between hosts is of key importance in epidemiology. Current studies have mainly focused on networks with stationary structures, although we know these structures to be dynamic with continuous appearance and disappearance of links over time. In the case of moving individuals, the contact network cannot be established. Individual-based models (IBMs) can simulate the individual behaviours involved in the contact process. However, with very large populations, they can be hard to simulate and study due to the computational costs. We use the moment approximation (MA) method to approximate a stochastic IBM with an aggregated deterministic model. We illustrate the method with an application in animal epidemiology: the spread of the highly pathogenic virus H5N1 of avian influenza in a poultry flock. The MA method is explained in a didactic way so that it can be reused and extended. We compare the simulation results of three models: 1. an IBM, 2. a MA, and 3. a mean-field (MF). The results show a close agreement between the MA model and the IBM. They highlight the importance for the models to capture the displacement behaviours and the contact processes in the study of disease spread. We also illustrate an original way of using different models of the same system to learn more about the system itself, and about the representation we build of it.
Insights
This study introduces a moment approximation (MA) method to efficiently model host contact dynamics in epidemiology. The MA model closely matches individual-based models (IBMs), improving disease spread simulations in animal populations.
Area of Science:
- Epidemiology
- Computational Biology
- Mathematical Modeling
Background:
- Epidemiological models often use static networks, but real-world host contact structures are dynamic.
- Simulating large populations with individual-based models (IBMs) is computationally intensive.
- Understanding host movement and contact is crucial for disease spread dynamics.
Purpose of the Study:
- To develop and validate a moment approximation (MA) method for approximating stochastic individual-based models (IBMs) in epidemiology.
- To assess the accuracy of the MA method compared to IBMs and mean-field (MF) models.
- To apply the MA method to model avian influenza (H5N1) spread in poultry flocks.
Main Methods:
- Developed a moment approximation (MA) method to create a deterministic model from a stochastic individual-based model (IBM).
- Compared simulation results from the MA model, an IBM, and a mean-field (MF) model.
- Applied models to simulate the spread of avian influenza (H5N1) in a poultry flock.
Main Results:
- The MA model demonstrated close agreement with the IBM simulations.
- The study highlights the necessity of incorporating host displacement and contact processes into epidemiological models.
- The MA method provides a computationally efficient alternative to IBMs for large populations.
Conclusions:
- The moment approximation (MA) method is a viable and accurate approach for modeling dynamic contact processes in epidemiological studies.
- Accurate representation of host behavior, including movement and contact, is essential for effective disease spread modeling.
- This work offers a reusable framework for approximating complex stochastic models in epidemiology and other fields.
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