What is trichomoniasis?

Causes and Symptoms

Flagellated motile protozoans known as Trichomonas vaginalis cause trichomoniasis, one of the most widespread and common of Sexually transmitted diseases (STDs). The disease is common among people with multiple sex partners, those who engage in unprotected sex, and those who seek services at STD clinics. Trichomoniasis in pregnant women is a leading cause of premature birth in the United States.

Some estimates suggest that 180 million people a year are infected with trichomoniasis worldwide. The most common population found to be infected is females sixteen to thirty-five years old, which is prime childbearing age. This is an important epidemiological group, as trichomoniasis infections are a leading cause of premature rupture of the placenta, premature birth, and low birth weight.

After infection, there is an incubation period of about seven days, with a range from about four to twenty days. Although up to 70 percent of infected women may remain asymptomatic, T. vaginalis infections may sometimes produce a frothy yellow or green vaginal discharge. Women’s symptoms may also include urethritis, vaginitis, and itching of the vulva. Sometimes, vaginal inspection shows a distinctive “strawberry cervix”
(red patches on the cervix) and red spots on the vaginal walls. Men’s symptoms sometimes include urethritis, dysuria, a frothy or purulent urethral
discharge, and, in rare cases, scrotal pain as the tube connecting the testicle with the vas deferens becomes inflamed.

The symptoms of infection by T. vaginalis are of questionable value in diagnosing the infection. In addition, many infected people remain asymptomatic for many years, and most existing tests, such as microscopic viewing of wet mounts, Pap tests, and polymerase chain reaction (PCR), often fail to show the infectious agent in people with symptoms. Culture of vaginal and urethral smears is considered to be the most effective way of detecting T. vaginalis infection. These factors add to the difficulty in reducing infection rates.

Treatment and Therapy

The CDC’s
Sexually Transmitted Diseases Treatment Guidelines 2006, which includes trichomoniasis, focuses on microbiological cure, alleviation of signs and symptoms, prevention of sequelae, and prevention of transmission.

The infection is treated with a single oral dose of either metronidazole or tinidazole. Any sex partner should be treated simultaneously even if he or she is asymptomatic. Treatment is successful in 90 to 100 percent of cases. Treatment during pregnancy is controversial, but no case of fetal malformation has been attributed to metronidazole. Studies have shown that trichomoniasis is associated with low infant birth-weight, premature rupture of the membranes, and preterm births. However, studies of pregnant women with trichomoniasis who are treated failed to show an improvement in preterm deliveries and even trended toward more preterm deliveries; therefore, treatment remains controversial.

Perspective and Prospects

Many men and women infected by the organism remain asymptomatic for years, spreading the disease to other people through sex. Safer sex practices help prevent transmission. People with multiple sex partners should use latex or polyurethane condoms to help curtail the spread of this disease. It is crucial that sex education programs emphasize that people with any unusual genital symptoms, including urethritis and vaginal discharge, seek medical treatment.

People infected by T. vaginalis may also be infected by other STD organisms, especially the bacterium that causes gonorrhea. Medical professionals believe that infection by the Trichomonas protozoan predisposes a person to infection by the human immunodeficiency virus (HIV) upon exposure through unprotected sex with infected partners.

Trichomoniasis in young children may indicate sexual abuse, and health professionals may be obligated to report such infections, if local regulations require it.

Bibliography

Boston Women’s Health Collective. Our Bodies, Ourselves: A New Edition for a New Era. 35th anniversary ed. New York: Simon & Schuster, 2005.

Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines. http://www.cdc.gov/std/treatment.

Heymann, David L., ed. Control of Communicable Diseases Manual. 19th ed. Washington, D.C.: American Public Health Association, 2008.

Scharbo-DeHaan, Marianne, and Donna G. Anderson. “The CDC 2002 Guidelines for the Treatment of Sexually Transmitted Diseases: Implications for Women’s Health Care.” Journal of Midwifery and Women’s Health 48 (February, 2003): 96-104.

Sommers, Michael. Yeast Infections, Trichomoniasis, and Toxic Shock
Syndrome (Girls' Health). New York: Rosen Publishing Group, 2007. Print.

Sutton, Amy L., ed. Sexually Transmitted Diseases Sourcebook. 3d ed. Detroit, Mich.: Omnigraphics, 2006.