Confined Random Walkers in Dimensions Higher Than One and Analysis of Transmission of Infection in Epidemics

TL;DR

This paper models the transmission of infection among confined animals in a 2D landscape using reaction-diffusion theory, revealing nonintuitive phenomena and providing a tool for analyzing epidemic spread in dilute systems.

Contribution

It extends reaction-diffusion analysis to confined 2D random walkers with spatially extended reaction regions, addressing complex infection transmission scenarios.

Findings

Revealed nonintuitive reaction behaviors in 2D confined systems

Developed a formalism for reaction regions larger than points

Provided a realistic model for animal-based infection spread

Abstract

A pair of random walkers, the motion of each of which in two dimensions is confined spatially by the action of a quadratic potential centered at different locations for the two walks, are analyzed in the context of reaction-diffusion. The application sought is to the process of transmission of infection in epidemics. The walkers are animals such as rodents in considerations of the Hantavirus epidemic, infected or susceptible, the reaction is the transmission of infection, and the confining potential represents the tendency of the animals to stay in the neighborhood of their home range centers. Calculations are based on a recently developed formalism (Kenkre and Sugaya, Bull. Math. Bio. 76, 3016 (2014)) structured around analytic solutions of a Smoluchowski equation and one of its aims is the resolution of peculiar but well-known problems of reaction-diffusion theory in 2-dimensions. In the present analysis, reaction occurs not at points but in spatial regions of dimensions larger than 0. The analysis uncovers interesting nonintuitive phenomena one of which is similar to that encountered in the 1-dimensional analysis given in the quoted article, and another specific to the fact that the reaction region is spatially extended. The analysis additionally provides a realistic description of observations on animals transmitting infection while moving on what is effectively a 2-dimensional landscape. Along with the general formalism and explicit 1-dimensional analysis given in Bull. Math. Bio. 76, 3016 (2014), the present work forms a model calculational tool for the analysis for the transmission of infection in dilute systems.