  Infectious diseases outbreaks are often characterized by a spatial component
induced by hosts' distribution, mobility, and interactions. Spatial models that
incorporate hosts' movements are being used to describe these processes, to
investigate the conditions for propagation, and to predict the spatial spread.
Several assumptions are being considered to model hosts' movements, ranging
from permanent movements to daily commuting, where the time spent at
destination is either infinite or assumes a homogeneous fixed value,
respectively. Prompted by empirical evidence, here we introduce a general
metapopulation approach to model the disease dynamics in a spatially structured
population where the mobility process is characterized by a heterogeneous
length of stay. We show that large fluctuations of the length of stay, as
observed in reality, can have a significant impact on the threshold conditions
for the global epidemic invasion, thus altering model predictions based on
simple assumptions, and displaying important public health implications.
