Accounting for farmers\u2019 control decisions in a model of pathogen spread through animal trade

Lina Cristancho Fajardo,Pauline Ezanno,Elisabeta Vergu

doi:10.1038/s41598-021-88471-6

Abstract

Accounting for individual decisions in mechanistic epidemiological models remains a challenge, especially for unregulated endemic animal diseases for which control is not compulsory. We propose a new integrative model by combining two sub-models. The first one for the dynamics of a livestock epidemic on a metapopulation network, grounded on demographic and animal trade data. The second one for farmers’ behavior regarding the adoption of a control measure against the disease spread in their herd. The measure is specified as a protective vaccine with given economic implications, and the model is numerically studied through intensive simulations and sensitivity analyses. While each tested parameter of the model has an impact on the overall model behavior, the most important factor in farmers’ decisions is their frequency, as this factor explained almost 30% of the variation in decision-related outputs of the model. Indeed, updating frequently local health information impacts positively vaccination, and limits strongly the propagation of the pathogen. Our study is relevant for the understanding of the interplay between decision-related human behavior and livestock epidemic dynamics. The model can be used for other structures of epidemic models or different interventions, by adapting its components.

Highlights

Accounting for individual decisions in mechanistic epidemiological models remains a challenge, especially for unregulated endemic animal diseases for which control is not compulsory
When human decision-making is explicitly taken into account, it generally focuses on the context of human diseases[13,14,15], but it has barely been applied to veterinary epidemiology yet[16]
In this paper we present a new integrative model for the epidemic spread of a livestock disease on a trade network, accounting for farmers’ dynamic decisions concerning the adoption of a control measure in their herd

Summary

Introduction

Accounting for individual decisions in mechanistic epidemiological models remains a challenge, especially for unregulated endemic animal diseases for which control is not compulsory. This consists in considering a stochastic decision mechanism where the probability of applying the measure is updated through the costs each farmer observes over time, and the costs observed by his/her neighbors. We explore an extension of the model where each farmer considers the decisions and costs observed by all of his/her neighbors at each decision time.

Results

Conclusion