In the United States, bacterial vaginosis disproportionately affects African American women, according to research reported Wednesday in Jacksonville, Florida at the 2006 National STD Prevention Conference sponsored by the Centers for Disease Control and Prevention. Trichomoniasis is also more prevalent among African-American women, according to related research reported at the meeting.

Bacterial vaginitis, the most common vaginal infection in women of childbearing age, occurs when the normal balance of bacteria in the vagina is disrupted and replaced by an overgrowth of other bacteria. The infection is sometimes accompanied by discharge, odor, pain, itching or burning.

Trichomoniasis is caused by the single-celled protozoan parasite, Trichomonas vaginalis, and is transmitted through sexual contact. Some but not all women develop a yellow-green vaginal discharge with a strong odor. It may also cause discomfort during intercourse and urination, as well as irritation and itching of the female genital area

The findings of a nationally representative sample of about 2000 women between the ages of 14 and 49 years old, indicate that more than one quarter of all U.S. women (27.4 percent) compared with half of non-Hispanic black women (50.3 percent) have bacterial vaginosis.

“Black women were about twice as likely as either white women, who had a prevalence of 22 percent, or Mexican-American women, who had a prevalence of 28 percent, to have bacterial vaginosis,” the CDC’s Dr. Emilia Koumans reported.

Factors associated with bacterial vaginosis were douching, having an annual family income less than $20,000, having been pregnant, black race, and for white women, increasing numbers of sex partners.

Using the same study data, Koumans and colleagues also found that the overall prevalence of trichomoniasis among U.S. women is 3 percent. However, among non-Hispanic black women, the prevalence is 13.5 percent.

“Black women were more than nine times more likely to be infected than either white women, who had a prevalence of 1.2 percent, or Mexican-American women, who had a prevalence of 1.5 percent,” Koumans reported.

As with many other STDs, the higher prevalence of trichomoniasis among black women likely reflects underlying socioeconomic factors, such as poverty and limited access to healthcare, and having a social network with a high prevalence of STDs.

“Trichomoniasis is easily treated, as is bacterial vaginosis, with a single dose of medication taken orally or with a course of intravaginal antibiotics,” Koumans said.

Summing up, Dr. John M. Douglas Jr., of the CDC noted that bacterial vaginosis and trichomoniasis are “extremely common but under recognized health threats for sexually active women and their babies.”

“Like many serious STDs in women, they often go undiagnosed and when left untreated they carry risks for potentially serious health problems including premature and low birth weight babies and an increased risk of acquiring HIV. Bacterial vaginosis is also associated with pelvic inflammatory disease, which can lead to infertility.”