Viral Evolution - Inter-host and Intra-host Evolution

Inter-host and Intra-host Evolution

In evolutionary virology and to an extent in the wider field of pathology, inter-host evolution is considered to represent the geological, i.e. visible or detectable, evolution of a virus while intra-host evolution represents the invisible evolution of a virus. Adaptive changes acquired by inter-host evolution are rarely lost once acquired. Changes acquired by intra-host evolution may be lost if the evolutionary landscape changes, for example: a population of viruses may become resistant to an antiviral drug while the host (patient) takes it, but rapidly revert to wild-type if treatment ceases. Viral Infection tend to have a short generation time and a relatively high mutation rate. Changes may include point mutations or epistatic mutations, as well as genome rearrangements to genes and other functional gene sequences such as gene acquisition, gene creation and gene deletion as well as recombination and translocation events.