An epidemic that is geographically widespread; occurring throughout a region
or even throughout the world.
Research has identified three prerequisites for the start of a pandemic.
- A novel virus subtype must emerge to which the general population will
have no or little immunity.
- The new virus must be able to replicate in humans and cause serious
- The new virus must be efficiently transmitted from one human to
another; efficient human- to-human transmission is expressed as sustained
chains of transmission causing community-wide outbreaks.
Avian Influenza: assessing the pandemic