Emergent Virus

Emergent virus refers to a virus as a causal agent that causes a new, previously unknown infection or becomes increasingly important when it spreads in a population at an unusually rapid rate and with a high incidence.

This epidemiological phenomenon may be caused by a cross-species host switch. The appearance of a new, more aggressive virus variant within the previous host species may also be responsible. Emergence due to, among other things:

• Mutation/recombination (influenza virus)
• Environmental changes (e.g. climatic changes, e.g. dengue virus). The terms "re-emerging or re-emerging viruses" are also used for this.
• Invasion of new areas (yellow fever, smallpox virus among the Aztecs)
• Discovery of a new pathogen as the cause of a known disease (e.g. hepatitis C virus)

There is a risk of a pandemic in the event of the emergence of new influenza viruses from human and animal viruses with efficient transmission from human to human. The prerequisite is the infection of the same cell (e.g. in animals - pigs, birds) with human and avian influenza virus (especially in the case of high prevalence of both viruses and close contact between animals and humans.