Some US soldiers who've returned from serving in Iraq have found they have one more enemy to face -- a tiny sand fly that causes stubborn and ugly sores that linger for months. One soldier undergoing treatment says so many of his fellow soldiers had the same sores he does that -- in his words -- "You ain't cool unless you got it." Doctors at the Walter Reed Army hospital in Washington have seen more than 600 cases of the infections that soldiers call the "Baghdad boil." The sores aren't painful or contagious, but left untreated they can last up to 18 months and leave permanent, burn-like scars. Since the flies bite exposed areas, many soldiers have sores on their necks, faces and arms.