Pandemic

http://www.youtube.com/watch?v=Mj9SUJdpJS4

http://dictionary.reference.com/browse/pandemic

http://learning.blogs.nytimes.com/2011/09/14/when-contagion-spreads-crowdsourcing-disease-outbreaks/

http://ed.ted.com/lessons/how-pandemics-spread

http://www.breakingnewsenglish.com/0910/091025-h1n1.html

http://dictionary.reference.com/browse/pandemic