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Sexually Transmitted Disease May Pave Way for HIV Infection

Black women at special risk from trichomoniasis

FRIDAY, Jan. 25, 2002 (HealthDayNews) -- The sexually transmitted disease dubbed "trich" is barely given a second thought by researchers because its symptoms are usually minor or non-existent.

However, a new study contends that the high rate of trichomoniasis among black women may make them more susceptible to infection by HIV, the virus that causes AIDS.

"The HIV infection in this country has moved aggressively into minority communities, especially African-American ones. Trichomoniasis may help explain that trend," says study co-author Frank Sorvillo, a professor of epidemiology at the University of California at Los Angeles.

Sorvillo and colleagues examined several studies on the relationship between trichomoniasis and AIDS in black women. They report their conclusions in the January issue of the journal Emerging Infectious Diseases.

While most sexually transmitted diseases (STDs) are caused by viruses or bacteria, trichomoniasis is caused by a parasite. The bug infects the genital area, mainly through vaginal intercourse. About half the infected women suffer from itching and genital discharge; the symptoms are much less pronounced for infected men.

There are not many statistics about trichomoniasis.

"It's been an understudied disease," says Dr. Hunter Handsfield, director of the King County public health department's STD Control Program in Seattle. "It's been looked at as a trivial sort of thing."

Handfield calls Sorvillo's study conclusions plausible.

Some researchers estimate that 5 million people in the United States are infected each year with trichomoniasis. One study of young black men in Washington, D.C., found that 55 percent were infected with the disease.

Like some other STDs, trichomoniasis can be spread even when victims don't notice symptoms, Handsfield says. "When they're not symptomatic, they're likely to continue engaging in sex."

Sorvillo contends that trichomoniasis can make someone more vulnerable to HIV, even if the victim doesn't know he or she is infected. Trichomoniasis causes tiny blood hemorrhaging in the genital area. As the immune system responds to the infection, white blood cells, which fight infection but also carry HIV, rush to the genital area.

That makes it easier for HIV to enter the bloodstream of someone whose sexual partner is HIV-positive, Sorvillo says. "It's like opening the gates and allowing greater flow of virus."

Studies in Africa have found that black women who are HIV-positive are one-to-three times more likely to also be infected with trichomoniasis. While those studies didn't prove which infection came first, another research project found that sex workers with trichomoniasis were twice as likely to become HIV-positive.

In the United States, studies of limited groups of black women show trichomoniasis infection rates ranging from 23 percent to 51 percent. Blacks, both men and women, also have higher rates of HIV infection that whites.

"If you put the two facts together, it indicates that trich [pronounced 'trick'] is probably responsible for a considerable amount of HIV transmission in the African-American communities of this country," Sorvillo says.

It's not clear why black women have higher rates of trichomoniasis infection. One of Sorvillo's colleagues notes they are more likely to douche, a practice that reduces their resistance to STDs.

Black men are also less likely to use condoms than white males, Sorvillo says.

"Clearly, there needs to be more research and more work done," he says. "We believe there's sufficient information to warrant screening and treating for trich."

That would require a major change in the mindset of doctors, who rarely check for the disease. To make matters more challenging, tests that detect trichomoniasis are either expensive or not totally accurate, says Handsfield. Even so, he adds, it might be wise to routinely screen people for the disease.

There is some good news on the treatment front. Unlike other STDs, which often require weeks or months of treatment, a single dose of medication will clear up trichomoniasis, Sorvillo says.

What to Do:To learn more about trichomoniasis, check the Centers for Disease Control and Prevention. For information about STDs, try the American Social Health Association.

SOURCES: Interviews with Frank Sorvillo, Ph.D., professor of epidemiology, University of California at Los Angeles; Hunter Handsfield, M.D., director, STD Control Program, public health department, King County, Seattle; January 2002 Emerging Infectious Diseases
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