It's not unheard of in Africa. It's called a "Sleeping illness" (from tonight's research on it) although I don't know why.
The tsetse fly and Tumbu fly (It's been a while since my insect disease pathology classes, forgive me) aren't interested in feeding from you, necessarily. The TseTse fly gives birth to one maggot. Which is nice. That one maggot matures inside the tsetse fly, and when it's ready to be released, the tsetse fly will inject your skin with a nerveagent (you won't feel a thing) and it will dig out a spot for the maggot, and drop it in. The Maggot eats you from the inside. tse tse is relatively painless.
Tumbu fly will, like a stinger, inject it's larvae into your skin, and the maggots mature inside of you. They stay in the body until they get about 2 mm long, and then go for the surface to leave you. It's there they will simply fall onto the ground (In an animal) or in a person, you'll pop em out like zits. This pictures is obviously an extreme case, and quite frankly I can't see how you could go so long without treatment of one sort or another.
The birthing area of your skin is usually about 3-6 cm's wide, and about that deep. Whereas TseTse flies eat your flesh, and chemically burn it to not grow back, the others will simply eat around and fall out - and you'll heal. I don't know about this woman healing though.