A sexually transmitted disease rarely seen in recent decades in the United States has reemerged in Boston and other American cities in the past six months, fostering fears that it could herald a new wave of infections of an even more dangerous disease, AIDS.
The return of lymphogranuloma venereum, known as LGV, to North America also illustrates the increasing globalization of infectious diseases in an era of rapid air transit and frequent travel for work and pleasure, disease specialists said.
At the Fenway Community Health clinic in Boston, for example, one patient told a physician he probably caught the germ while visiting Brazil; the disease is endemic to Latin America, Africa, and Southeast Asia. Disease trackers who investigated a cluster of cases in the Netherlands in 2003 found that infected patients had multiple sex partners across Europe and the United States.
''This is probably a case of biological tourism," said Dr. Daniel Cohen, a specialist in infectious diseases who has treated patients with the condition at the Fenway clinic. ''It just points out that we live in a global community and that illnesses are no longer confined by geographical boundaries."
Since January, six cases of LGV have been confirmed in Massachusetts, according to Dr. Alfred DeMaria, the state's director of communicable disease control.
The US Centers for Disease Control and Prevention is sufficiently concerned by the reappearance of the bacterial infection that it is working to establish a surveillance system to monitor the disease nationwide and to develop better screening for it in health clinics. Dr. Hillard Weinstock, a medical epidemiologist at CDC, said the agency hopes to have those measures in place within six months.
So far, incidences of the disease in the United States appear to be limited to gay and bisexual men, and infectious disease specialists said they fear that it could be another signal that after years of hewing to safe-sex practices, gay men are returning to riskier behaviors.
''We hadn't seen an LGV case for years," DeMaria said. ''It's definitely a sign of unsafe sex, and that's a concern in terms of other sexually transmitted diseases and HIV. Now, I think we're at the point that people need to pay attention to it."
For several years, DeMaria and other disease specialists have been sounding an alarm about sharp increases in syphilis and gonorrhea cases among gay men. After AIDS dawned in the 1980s, gay men dramatically altered their sexual behavior. The result: Rates of sexually transmitted diseases plummeted.
That changed with the arrival of potent drug cocktails that fundamentally altered the course of the epidemic in the developed world. AIDS went from a presumed death sentence to a chronic, but treatable, medical condition, and, at the same time, some gay men grew weary of the safe-sex messages that had blared for nearly two decades.
Studies demonstrated that patients infected with gonorrhea and syphilis were far more likely to become infected with HIV -- and not just because it indicated sexual risk-taking. The sores generated by a condition such as syphilis, researchers found, provide a portal for the AIDS virus to get into the bloodstream.
They fear the same could be true with LGV.
''This would fit at least on a theoretical basis," said Dr. David Hamer, a specialist in infectious disease and global health at the Boston University School of Public Health. ''It's always worrisome when you see a pathogen that's not common in developed countries suddenly appear."
LGV is typically transmitted during unprotected anal or vaginal intercourse, and spreads from genital bumps or lesions that leak pus or blood carrying the bacteria.
Symptoms can appear days after exposure or it can take as long as a month. Signs of illness, including rectal bleeding and abdominal pain, can frequently be misidentified as Crohn's disease or other intestinal conditions.
A definitive blood test for LGV does not exist, so ascertaining the presence of the disease requires using a swab to take a sample from a sore and analyzing the contents using sophisticated laboratory techniques.
''We will be working with state labs to set up testing," said Weinstock, who works in the CDC's Division of Sexually Transmitted Disease Prevention. ''My degree of concern is one of wanting to be prepared, wanting to be equipped to be ready to identify increases in this disease where they occur."
Left untreated, small sores can grow and lymph nodes in the groin can swell to the point of protruding through skin. The disease can also disfigure genitalia and permanently damage the bowels.
''If it does not get treated, it can get worse and worse and can even become life-threatening," Cohen said. ''But that's unusual because fortunately in the developed world, people with symptoms will seek care, and they will get treated for this before it gets to the point of being life-threatening."
The disease can be cured with a three-week course of the antibiotic doxycycline.
Rather than just treating the disease, public health authorities are now looking for ways to prevent it. Maybe, they said, the specter of yet another germ transmitted through risky sexual practices will compel the use of condoms.
''By now," said Dr. Anita Barry, top disease physician at the Boston Public Health Commission, ''the one thing we know for sure is that it's a challenge to get people to change their behavior."
Stephen Smith can be reached at email@example.com.