actually you don't catch it, you're usually born with it -- but that's pretty much what I'm getting at
ignorance is just a matter of not knowing something, and all you have to do to correct it is learn the something you don't know -- people use the two interchangably but they're NOT the same meaning at all
I've never understood why people get all bent out of shape if you call them ignorant, but will cheerfully accept being called stupid (heh, unless it's a matter of being totally 'ignorant' of the actual meanings of the two words)

lewl I dun know, now *brain farts*