In this activity, two teams analyze a specific pathogen-host interaction assessing various components of pathogen virulence (Team 1) and host defense (Team 2). Members of the "pathogen team" research the virulence factors of their assigned pathogen while members of the "host team" determine the defense factors operative in their assigned host. Each team fills in a worksheet assigning point values (out of 100 points total) to 5 categories of pathogen virulence or host defense. In class, the interaction is simulated as the teams confront each other comparing the components of host-parasite interaction over the course of the infection. For each of the 5 categories, the team assigning the higher point value prevails and the team winning the greater number of stages "wins" the immune war. This exercise provides the students, both as individuals and in groups, an opportunity to analyze, integrate, and discuss course material on virulence and immunity in a case-study–game format.