An epidemic is a disease that affects many people at the same time, such as the flu. The US Centers for Disease Control and Prevention's official definition of epidemic is: 'The occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time'. A pandemic is a
very extensive epidemic
, like a plague, that is prevalent in a country, continent, or the world. There is also the word
endemic, which is a disease native to a people or region, which is regularly or constantly found among a people or specific region. The term outbreak describes the sudden rise in the incidence of a disease, especially a harmful one. An outbreak is characterized by a disease's
bypassing of measures to control it. Often, the difference between these terms is determined by the percentage of deaths caused by the disease.
Could you please explain to me what "extensive" and "bypassing" means here?
Source :
http://dictionary.reference.com/help/faq/language/d24.html