Hi Curtis. Good morning.  You are probably going to get several hundred
answer in your electronic mail box!  But just in case that the "wise guys"
think that it is "dumb" not to know what AFB, I am answering your question.
 
AFB stands for American Foul Brood disease.  A bacterium that reproduces
forming spores and very capable of destroying an apiary in short order.
With good sanitary practices, people don't have to worry about AFB.  But,
as a rule, beekeepers tend to be sloppy, and pay the consequences.  The
mite infestation is a good example of that!
Have a wonderful day, my friend.
Pedro