Natural history of viruses of the intestine in contrasting ecosystems: implications for health

Abstract

Many different viruses have the capacity for infecting and replicating in micro-habitats of the intestinal tract. Eons of interaction between intestinal viruses and the intestinal mucosa have lead to a variety of host-parasite interrelationships, most of which are superficially known or hitherto unsuspected. Our knowledge has been determined in great part by advances in biotechnology and its capacity to recognize and study such viruses. On the other hand, changes in scientific interest and in funding have shifted research interest from the enteroviruses to the rotaviruses at a paint where our understanding of the first was still insufficient. This is unfortunate because information for contrasting ecosystems, for instance, within developing countries is even more incomplete than for industrial countries. Enteroviruses and adenoviruses still play important role in disease causation everywhere. From an evolutionary perspective, the intestinal tract can be considered invagination of external integuments, and, therefore, thousands of years evolutionary adaptations led to specialization and development of myriads bacteria, protozoa, yeasts and viruses in the intestinal habitats. Such changes explain the varying pathogenicity of agents and, in some Instances, their coexistence within the human host.