A pandemic<span> (from Greek πᾶν pan "all" and δῆμος demos "people") is an </span>epidemic<span> of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide.</span>
An epidemic is a spread of a disease that affects more people than is usual for the locality or one that spreads to areas not associated with the disease.
a pandemic is an epidemic of worldwide proportions
