Quote Originally Posted by tell it like it is View Post
Even that image is a gross simplification. It implies people only have one potential source of infection. The way that's presented, a 1 to 1 relationship means that knocking one "source" out ( by isolating ) prevents others along that source tree further down the line getting it. It's nowhere near as simple as that.
It's supposed to get a message across, not be an exact replica of what will happen and it's very effective at doing that.