A
pandemic (from
Greek πᾶν
pan "all" and δῆμος
demos "people") is an
epidemic of
infectious disease that has spread through human populations across a large region; for instance multiple
continents, or even worldwide. A widespread
endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic. Further,
flu pandemics generally exclude recurrences of
seasonal flu. Throughout history there have been a number of pandemics, such as
smallpox and
tuberculosis. One of the most devastating pandemic was the
Black Death, killing over 75 million people in 1350. The most recent pandemics include the
HIV pandemic as well as the
1918 and
2009 H1N1 pandemics.