Epidemics and pandemics, are when you get a sudden burst of an infection. It can be a relatively small outbreak. It can be a fairly severe one in a localized area. For example, the Ebola epidemic that hit West Africa a few years ago or it can be massive like the flu pandemic of 1918 This is the centenary year of that epidemic which actually killed somewhere between 50 and 100 million people. Some epidemics are passed on by insects like mosquitoes or fleas. Some are passed on by airborne methods some are passed on by food and water. Some are passed on sexually and some are passed on by touch and depending which of these it is we can do different things to try and control them.