The importance of The Gale Database
This article from the Gale Database talks about some characteristics of diseases and epidemics. It goes in depth about the longevity of some diseases and the extent of a few specific diseases as in an epidemic. The article mentions that some diseases can occur as an epidemic one year, and go away for 30 years and can come back to infect a population. Some diseases have been with humanity for thousands of years and some are as new as 1980. It touched on how diseases are spread. A traveler with built up immunity to a carried disease moves through a new country infecting indigenous people with no immunity or tolerance to the disease. This now has a potential to diffuse through the country infecting the population. After that, there’s talk about contagious diseases to insect borne viruses.
"Emergent diseases (human)." Environmental Encyclopedia. Gale, 2011. Science in Context. Web. 6 Apr. 2016.