If you have listened to the news in recent years you have heard the word, pandemic. Wikipedia defines a pandemic as an epidemic of infections disease that is spreading through human populations across a large region.
Since the 20th century one of the most deadly has been HIV/AIDS, a disease caused by the human immunodeficiency virus. Since AIDS was first recognized in 1981, it has led to the deaths of more than 25 million people, making it one of the most destructive diseases in recorded history. The H1N1 virus is a flu virus strain that is causing illnesses in humans worldwide. In June 2009, the World Health Organization declared a worldwide flu pandemic. Pandemics spread quickly by human-to-human transmission contact.
