Yeah, the only real hints that it was fake were the bits about people volunteering to be infected with them, and the part where the foundation doesn't take donations so they can remain non-partisan.
But, in all seriousness, I think we should at least sequence this thing's genome before we purposely cause its extinction. Who knows if some enzyme it secretes might be valuable to modern medicine?
http://www.deadlysins.com/guineaworm/index.htm
Took some Googling for me to verify that it's indeed a joke.