Anticipating persistent infection

Abstract

We explore the emergence of persistent infection in a closed region where the disease progression of the individuals is given by the SIRS model, with an individual becoming infected on contact with another infected individual within a given range. We focus on the role of synchronization in the persistence of contagion. Our key result is that higher degree of synchronization, both globally in the population and locally in the neighborhoods, hinders persistence of infection. Importantly, we find that early short-time asynchrony appears to be a consistent precursor to future persistence of infection, and can potentially provide valuable early warnings for sustained contagion in a population patch. Thus transient synchronization can help anticipate the long-term persistence of infection. Further we demonstrate that when the range of influence of an infected individual is wider, one obtains lower persistent infection. This counter-intuitive observation can also be understood through the relation of synchronization to infection burn-out.

Localized spatial distributions of disease phases yield long-term persistence of infection

“…In order to quantify the long-term persistence of disease we use a persistence order parameter 〈〈 I t 〉〉 defined in refs. 27,30 . This quantity is the fraction of infected individuals in the entire population, averaged over time of the order of several disease cycles (after long transients), and further averaged over a large sample of random initial conditions.…”