CDC Alert: Lesser Known, Potentially Serious STDs on the Rise

June 3, 2007
Rebekah McCallister

Internal Medicine World Report, June 2006, Volume 0, Issue 0

JACKSONVILLE, Fla?New data presented at the Centers for Disease Control and Prevention (CDC) 2006 National STD Prevention Conference show that the prevalence of bacterial vaginosis (BV) and trichomoniasis among women is high. The findings also provide new insight into risk factors for lymphogranuloma venereum (LGV) among men who have sex with men (MSM).

Trichomoniasis, Bacterial Vaginosis

The first national data on the prevalence of BV in women show that more than one quarter of women overall, and 50% of black women, are affected. An analysis of a nationally representative health survey of nearly 2000 women conducted in 2001 and 2002 determined that 27.4% of women had BV, including 50.3% of blacks, 22.4% of whites, and 28.8% of Mexican Americans.

A separate analysis of the same 2000 women showed that 1 in 8 black women were infected with the parasite that causes trichomoniasis, and that overall prevalence among American women was 3%. The prevalence of 13.5% among black women was >9 times higher than that among white or Mexican-American women (1.2% and 1.5%, respectively).

An additional multi-city study of female patients at sexually transmitted disease (STD) clinics found that nearly 1 in 7 became infected with the trichomonas parasite over a 1-year period; older women and black women were at greatest risk. Overall, 13% of women became infected. In contrast to many other STDs, women aged 35 to 39 years were most susceptible to developing infection, accounting for 22.9% of cases.

"One surprising finding emerged, as women in their 30s were more likely to become infected than adolescents," said John M. Douglas, Jr, MD,director, Division of STD Prevention at the CDC's National Center for HIV, STD, and TB Prevention. "These results contrast with many other STDs, such as chlamydia, which are most common among women under 25. The research team is not yet sure why older women had a higher incidence of the disease in this study, and additional research will be needed to further our understanding of risk factors for this disease."

He added, "Taken together, these studies point to high levels of BV and trichomycosis, especially among African-American women, and represent an important public health challenge. These common diseases can increase HIV risk and threaten reproductive health, and yet many women remain unaware of the threat. It's critical that we raise awareness of the full range of STDs that can threaten women's health....This includes making sure that providers are aware of the signs and symptoms of the diseases and are equipped to diagnose and treat them when necessary."

Lymphogranuloma Venereum

A far less common STD than trichomoniasis or BV, LGV still poses a severe health risk and is becoming increasingly common in urban areas.

"LGV is caused by a particular form of chlamydia bacteria and requires a lengthier course of treatment than other forms of chlamydia. The most common symptoms are bleeding and inflammation of the rectum and colon and can include other gastrointestinal [GI] problems, such as abdominal cramping and pain," Dr Douglas explained.

Although LGV is prevalent in parts of Africa, Asia, and South America, it was rarely diagnosed in the United States and Europe until recent outbreaks among MSM. Since initial cases among MSM were identified in the United States beginning in late 2004, LGV has emerged as a new public health challenge.

Data released from the New York City Department of Health and Mental Hygiene included an analysis of 249 specimens collected in 2004 and 2005 from suspected LGV cases that identified links between LGV, HIV, and syphilis among MSM.

Almost all the LGV cases (97%) occurred among MSM, and most patients diagnosed with the disease (65%) reported unprotected receptive anal intercourse within the previous 6 months. In addition, 84% of those with LGV were coinfected with HIV, and nearly half (48%) had a previous syphilis diagnosis. When data were compared between men diagnosed with syphilis and men diagnosed with LGV, both LGV and syphilis were associated with a similar race/ethnicity and behavioral-risk profile.

"We found no apparent epidemiological links between cases that have been reported in Europe, despite the similarity of the LGV strain detected in New York City and overseas," said coinvestigator Preeti Pathelo, MD, of the New York Department of Health and Public Hygiene. "Thus, it appears that messages for interrupting the spread of LGV can be targeted to the same groups of men for whom syphilis prevention activities are already in place. These include education about both diseases and safer sex practices, and the need for increased screening for STDs. It is also important that health care providers be aware of the link between HIV and LGV in MSM."

Diagnosis has been hindered by symptoms that often mimic those of other anorectal problems. The lack of a quick and easily administered test for LGV has also posed challenges. "Very few labs have the capacity to test anorectal specimens for LGV, and the most suspected cases are referred to the CDC," Dr Pathelo said.

In an effort to speed up the diagnostic process, the CDC has developed a new test for quick and accurate diagnosis. The new experimental test works by identifying the DNA associated with the chlamydial strains that cause LGV and produces results in just a few hours.

"Once validated, the CDC plans to offer the technology to public health labs on a regional basis. This would increase the number of areas where LGV testing could be completed locally and could enhance STD surveillance efforts," Dr Douglas said.

Until the test becomes available, however, "the CDC recommends that physicians presumptively treat suspected cases of LGV rather than waiting for test results," he added.