WASHINGTON (AP) _ 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 diagnose: Few U.S. clinics and laboratories can test for it. Painful symptoms can be mistaken for other illnesses, such as irritable bowel syndrome.
And because LGV chlamydia doesn't always cause noticeable symptoms _ right away, at least _ an unknown number of people may silently harbor and spread it, along with an increased risk of HIV transmission.
``My feeling is that what we're seeing now is still the tip of the iceberg,'' says Dr. Philippe Chiliade of the Whitman-Walker Clinic in Washington, D.C., which diagnosed its first few cases of LGV last month and is beginning to push for asymptomatic men to be screened.
The Centers for Disease Control and Prevention already was counting an 8 percent increase in HIV among gay and bisexual men between 2003 and 2004, before LGV's arrival was recognized.
``We are really concerned about this,'' says Dr. Catherine McLean of CDC's HIV and STD prevention program.
Increasing the ability to test for LGV is ``what's really critically important,'' she adds. ``The prevalence of the disease is probably quite a bit higher than the reported cases indicate, either here or in Europe, but we don't yet know that.''
Three weeks of the antibiotic doxycycline effectively treats LGV. But patients have to know they're at risk, and then find a test.
Chlamydia, caused by bacteria, is among the most common sexually transmitted diseases. As many as 3 million Americans a year may become infected with common strains, best known for causing infertility in women if left untreated.
This more virulent strain is called ``lymphogranuloma venereum,'' or LGV. It's not a new form, but one rarely seen outside of Africa or Southeast Asia. So STD specialists were stunned in late 2004, when the Netherlands announced an outbreak that reached over 100 cases; last summer, one clinic there reported seeing one to two new patients a week. Cases also have surfaced in much of Western Europe and Britain. As with the U.S. cases, many also have HIV.
Symptoms differ from regular chlamydia: swollen lymph nodes in the groin; genital or rectal ulcers; and painful bowel movements and other gastrointestinal symptoms that may mimic inflammatory bowel disease. Such symptoms leave patients particularly susceptible to HIV infection if they also encounter that virus.
LGV can infect both sexes, although new cases diagnosed so far are among men having sex with men.
Screening requires nucleic acid testing, a complex type of genetic testing not yet commercially available for rectal use. The CDC then uses even more sophisticated testing to confirm the diagnosis.
Because testing is difficult, no one knows how prevalent LGV truly is. In a surprise finding last fall, Dutch scientists tested some tissue samples stored in San Francisco since the 1980s, and found evidence that today's LGV strain had gone unrecognized at the time. So has it been simmering here all along, or is it on the rise?
Regardless of how that question turns out, LGV is one more sexually transmitted illness that plays a role in HIV.
Thus, the CDC is encouraging doctors who spot LGV symptoms to contact their local health department for help in finding a nearby testing lab, or in shipping samples to CDC for testing there.
``But I don't want people to think you have to have severe pain,'' cautions Chiliade, whose clinic recently became authorized to offer the NAT rectal screening _ and who recommends it for gay men who have had unprotected sex even if they feel no symptoms.