  The movie Ben-Hur highlights the dynamics of contagion associated with
leprosy, a pattern of forced aggregation driven by the emergence of symptoms
and the fear of contagion. The 2014 Ebola outbreaks reaffirmed the dynamics of
redistribution among symptomatic and asymptomatic or non-infected individuals
as a way to avoid contagion. In this manuscript, we explore the establishment
of clusters of infection via density-dependence avoidance (diffusive
instability). We illustrate this possibility in two ways: using a
phenomenological driven model where disease incidence is assumed to be a
decreasing function of the size of the symptomatic population and with a model
that accounts for the deliberate movement of individuals in response to a
gradient of symptomatic infectious individuals. The results in this manuscript
are preliminary but indicative of the role that behavior, here modeled in crude
simplistic ways, may have on disease dynamics, particularly on the spatial
redistribution of epidemiological classes.
