What is the difference between Pandemic and epidemic?
An epidemic is when new cases of a given disease spread throughout a given population at a rate that is greater than would normally be expected. The disease in question doesn't have to be contagious to fit the definition of epidemic. As far as a pandemic goes, you might say it is an epidemic on steroids. By that I mean, that when an epidemic spreads over a large area--over a continent, several continents, or even global--it becomes a pandemic. If the number of people who are becoming sick with the epidemic disease is stable (meaning the disease is spreading over a great distance, but the number of people who are sick at any given time is remaining relatively the same), then it is not a pandemic. Finally, for a disease to meet pandemic criteria, it must be infectious.