Strategies of Virus Persistence

Viruses have evolved a wide range of strategies by which they persist in the population, in the individual, and in cells in culture. Within the population, antigenic variation is an important means by which some viruses continue to cause disease, but population density and viruses transmissibility also contribute to virus survival. In the individual host, many viruses perist by avoiding the immune response of the host through integration into cellular DNA or latent infection of nerve cells. Alternatively, the host immune response may be rendered ineffective by replication of the virus within lymphoreticular cells, or formation of infectious virus-antibody complexes. Finally, viruses are found to persist in cell cultures in vitro by limited growth in a cell subpopulation, (carrier culture), continuous multiplication without maturation (intracytoplasmic persistence) or integration into the host cell chromosome (latent infection).