A compartmental model for Xylella fastidiosa diseases with explicit vector seasonal dynamics

The bacterium Xylella fastidiosa (Xf) is mainly transmitted by the spittlebug, Philaenus
spumarius, in Europe, where it has caused significant economic damage to olive and almond
trees. Understanding the factors that determine disease dynamics in pathosystems that share
similarities can help design control strategies focused on minimizing transmission chains. Here
we introduce a compartmental model for Xf-caused diseases in Europe that accounts for the
main relevant epidemiological processes, including the seasonal dynamics of P. spumarius.
The model was confronted with epidemiological data from the two major outbreaks of Xf in
Europe, the olive quick disease syndrome (OQDS) in Apulia, Italy, caused by the subspecies
pauca, and the almond leaf scorch disease (ALSD) in Majorca, Spain, caused by subspecies
multiplex and fastidiosa. Using a Bayesian inference framework, we show how the model
successfully reproduces the general field data in both diseases. In a global sensitivity analysis,
the vector-plant and plant-vector transmission rates, together with the vector removal rate,
were the most influential parameters in determining the time of the infected host population
peak, the incidence peak and the final number of dead hosts. We also used our model to check
different vector-based control strategies, showing that a joint strategy focused on increasing
the rate of vector removal while lowering the number of annual newborn vectors is optimal for
disease control.

Also available from BioRxiv at https://doi.org/10.1101/2022.12.10.519878