The Diffusion Metrics of African Swine Fever in Wild Boar

TL;DR

This study models the early spread of African Swine Fever in wild boar as a diffusion process using real data from Germany, providing interpretable metrics to aid in outbreak control.

Contribution

It introduces a novel diffusion-based modeling approach using random walks to quantify early ASF spread dynamics in wild boar populations.

Findings

Diffusion process accurately describes early ASF spread in Germany

Derived diffusion constant and outbreak velocity metrics

Metrics are robust and adaptable to different regions

Abstract

To control African swine fever (ASF) efficiently, easily interpretable metrics of the outbreak dynamics are needed to plan and adapt the required measures. We found that the spread pattern of African Swine Fever cases in wild boar follows the mechanics of a diffusion process, at least in the early phase, for the cases that occurred in Germany. Following incursion into a previously unaffected area, infection disseminates locally within a naive and abundant wild boar population. Using real case data for Germany, we derive statistics about the time differences and distances between consecutive case reports. With the use of these statistics, we generate an ensemble of random walkers (continuous time random walks, CTRW) that resemble the properties of the observed outbreak pattern as one possible realization of all possible disease dissemination patterns. The trained random walker ensemble yields the diffusion constant, the affected area, and the outbreak velocity of early ASF spread in wild boar. These quantities are easy to interpret, robust, and may be generalized or adapted to different regions. Therefore, diffusion metrics can be useful descriptors of early disease dynamics and help facilitate efficient control of African Swine Fever.