I’ve created a quick project with Unity which lets you see a virtual virus spreading among “people” conveniently standing in a grid formation. Each box represents a person and starts off as green, except for one unfortunate individual in the middle who has been infected and is shown in red. Anyone within range has a small percentage chance of picking up the virus, but once the virus has run its course, this person will now be immune (blue).
There are some hard-wired parameters, but I haven’t yet exposed these for you to edit (this is just 30 minutes of work to get this far). I may take this a bit further, but you can download it in the meantime if you like. Just extract the zip file into an empty folder, then run Infection Visualiser.exe. Once the visualisation is complete, press ALT-F4 to quit.