Plagues

An infected agent may spread a virus to other agents he comes near. How close depends on how contagious the virus is. When the virus is passed to another agent, the agent may or may not get infected depending on its resistance. An infected agent may eventually die depending on the virulence of the virus.

Here's a screen shot of a lab for experimenting with these parameters.

The full model can be found in virus.nlogo.

Of course "virus" can refer to an actual virus, but it can also be interpreted more broadly to refer to any pathogen, such as a bacterium. It can be interpreted more broadly still to refer to a computer virus, a fad, a fashion, an idea (e.g., religion, democracy, an invention,) a meme (e.g. slogan, chain letter, joke, story, hoax, jingle,) information (e.g., rumors or information about a new product), nodes in an expanding network (e.g., "friends" in a social network such as Face Book), etc.

With these non-standard interpretations of "virus," how can we interpret virulence, mobility, contagiousness, and resistance?

AIDS

The AIDS model in the Biology library is a good example of a useful tool for experimenting with different policies to slow the spread of AIDS.