Amplification and spread of viruses in a growing plaque

The two-dimensional propagation of viruses through a "lawn" of receptive ho sts, commonly called plaque growth, reflects the dynamics of interactions b etween viruses and host cells. Here we treat the amplification of viruses d uring plaque growth as a reaction-diffusion system, where interactions amon g the virus, uninfected host cells, and virus-producing host-virus complexe s are accounted for using rates of viral adsorption to and desorption from the host-cell surface, rates of reproduction and release of progeny viruses by lysis of the host, and by the coupling of these reactions with diffusio n of free virus within the agar support. Numerical solution of the system s hows the development of a traveling wave of reproducing viruses, where the velocity of the wave is governed by the kinetic and diffusion parameters. T he model has been applied to predict the propagation velocity of a bacterio phage plaque. Different mechanisms may account for the dependence of this v elocity on the host density during early stages of a growing plaque. The mo del provides a means to explore how changes in the virus-host interactions may be manifest in a growing plaque. (C) 1999 Academic Press.