Molecular and Evolutionary Mechanisms of Viral Emergence

Abstract

A clear division among viruses-which has found no exceptions so far-is between those that use DNA and those that use RNA as genetic material. This chapter focuses on this difference that affects virus biology in ways that are highly relevant to viral disease emergence. The emergence of viral disease has some common underlying mechanisms that have been summarized in general terms. These mechanisms are illustrated with three very dissimilar viral systems: the picornavirus foot-and-mouth disease virus (FMDV), several arboviruses, and the arenaviruses. The incessant generation of diversity in our virosphere, in particular among the RNA viruses, acts as the fuel for the parasitic genetic elements to find new ecological niches where to thrive. Viral disease emergence is just a manifestation of the highly opportunistic nature of genetic elements whose major dictum is replicate and survive.