By STEPHEN MANNING, Associated Press WriterWASHINGTON - Staff Sgt. Eric DiVona didn't notice the small bumps on his face and left earlobe until he returned from serving nine months in Iraq (news - web sites). Nothing much, he thought, probably just a spider bite. But soon those bumps erupted into open sores, one growing to the size of a half dollar. AP Photo What DiVona thought was a spider bite was actually caused by a tiny sand fly with a fierce parasite stewing in its gut, an organism that causes stubborn and ugly sores that linger for months. The...