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

TL;DR

This paper presents a compartmental model for Xylella fastidiosa disease dynamics in Europe, explicitly incorporating seasonal vector behavior, and evaluates control strategies based on model simulations and data fitting.

Contribution

The study introduces a novel compartmental model that explicitly accounts for seasonal vector dynamics and fits it to European outbreak data, aiding disease control planning.

Findings

Model successfully reproduces outbreak data

Vector removal and transmission rates are key factors

Combined vector control strategies are most effective

Abstract

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.