With spring in full bloom, “boot camp flu” is back with a vengeance. A mysterious and virulent strain of the virus linked to last weekend's death of a Security Forces airman on Lackland AFB, it has sickened 237 recruits and technical school students at the base since Jan. 1. Only three of them landed in the base hospital, but all contracted adenovirus serotype 14. Things have been worse at Lackland, which in the past two years has seen two airmen die after contracting adeno 14, as well as hundreds of flu-like cases that have put thousands out of training and...