Critical behavior of a vector-mediated propagation of an epidemic process

We investigate the critical behavior of a model that mimics the propagation of an epidemic process over a population mediated by a density of diffusive individuals which can infect a static population upon contact. We simulate the above model on finite chains to determine the critical density of vectors above which the system achieves a stationary active state with a finite density of infected individuals. Further, we employ a scaling analysis to determine the order parameter, correlation length and critical relaxation exponents. We found evidences that this model does not belong to the usual direct percolation universality class. (C) 2004 Published by Elsevier B.V.