Abstract
The traditional concept of development of highly contagious forms of flu virus assumes that flu virus with pandemic potential arises as result of mutation and/or genetic recombination events in flu viruses of avian, human or other origin. A significant role in the development of a flu epidemic (pandemic) can be attributed to the appearance in the human population of a large group of people who have never had previous contact with the new variant of flu virus. On the basis of data in the literature, this paper proposes that in any discussion of the pathogenesis of flu and other virus infections it is important to keep in mind that in natural conditions among viruses (as in prokaryotic organisms) microecological processes such as interspecies horizontal gene transfer, microbe/microbe interactions (intracellular virus quorum sensing) and bacteria/virus/host crosstalk may take place. It is suggested that maintenance of the normal host microflora is important for protection against both bacterial and viral infections.