  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.
