WASHINGTON -- A particularly bad strain of chlamydia not usually seen in this country appears to be slowly spreading among gay and bisexual men, an infection that can increase their chances of getting or spreading the AIDS virus. Called LGV chlamydia, this sexually transmitted disease has caused a worrisome outbreak in Europe, where some countries have confirmed dozens of cases. Diagnoses confirmed by U.S. health officials still are low, just 27 since they warned a year ago that the strain was headed here. But specialists say that's undoubtedly a fraction of the infections, because this illness is incredibly hard to...