Cholera: Virulence, Origin, and Pandemics Merriam Webster’s Tenth Edition College Dictionary describes virulence as the rapid course, severity, or malignancy of a disease or infection caused by a microorganism [pathogen] to overcome body defenses of the host. Ewald (1) looks at virulence in two spectrums depending upon mortality rates of the infected hosts. The first, analogous to the human immunodeficiency virus (HIV), is one in which all hosts that become afflicted with the pathogen ultimately die due to progression of the virus—namely acquired immune deficiency syndrome (AIDS) in this example. Since the mortality rate is 10