Have You Ever Lost a Limb to a Spider Bite?

A bite from a brown recluse spider can cause terrible gangrene and necrosis, and people have lost life and limb before. This concerns me. How common is this? Do you know anyone who has been affected? I live in the tropical wilderness and all kinds of bugs and creatures are always sneaking into my house. Am I just paranoid?

P.S.: Here are some gross photos:

http://www.brown-recluse.com/bitephotos.html