Trichomoniasis

Trichomoniasis is one of the most common sexually transmitted diseases (STDs). An estimated 7.4 million new cases occur in men and women every year in the United States. The disease is caused by the single-celled protozoan parasite, Trichomonas vaginalis. The vagina is the most common site of infection in women, and the urethra (urine canal) is the most common site of infection in men. The parasite is sexually transmitted through penis-to-vagina intercourse or vulva-to-vulva (the genital area outside the vagina) contact with an infected partner. Women can acquire the disease from infected men or women, but men usually contract it only from infected women.

Symptoms and Diagnosis

Trichomoniasis, like many other STDs, often occurs without any symptoms. Most infected men do not have symptoms. When women have symptoms, they usually appear within 5 to 28 days of exposure to the parasite.

Although some infected women have minor or no symptoms, many do have symptoms. The symptoms in women include

• Heavy, yellow-green or gray vaginal discharge
• Discomfort during sex
• Vaginal odor
• Painful urination

They may also have irritation and itching of the genital area and, on rare occasions, lower abdominal pain.

If present, the symptoms in men include a thin, whitish discharge from the penis and painful or difficult urination and ejaculation.

A health care provider can perform a physical examination and laboratory test to diagnose trichomoniasis. The parasite is harder to detect in men than in women. In women, a pelvic examination can reveal small red ulcerations (sores) on the vaginal wall or cervix.

Complications

The genital inflammation caused by trichomoniasis can increase a woman's susceptibility to HIV infection if she is exposed to the virus. Having trichomoniasis may increase the chance that an HIV-infected woman passes HIV to her sex partner(s).

Pregnant women with trichomoniasis may have babies who are born early or with low birth weight (less than five pounds).

Treatment

Trichomoniasis can usually be cured with the prescription drug, metronidazole, given by mouth in a single dose. The symptoms of trichomoniasis in infected men may disappear within a few weeks without treatment. However, an infected man, even a man who has never had symptoms or whose symptoms have stopped, can continue to infect or re-infect a female partner until he has been treated. Therefore, both partners should be treated at the same time to eliminate the parasite. Persons being treated for trichomoniasis should avoid sex until they and their sex partners complete treatment and have no symptoms. Metronidazole can be used by pregnant women.

Having trichomoniasis once does not protect a person from getting it again. Following successful treatment, people can still be susceptible to re-infection.

References:

Centers for Disease Control and Prevention, USA.
National Institute of Allergy and Infectious Diseases, USA.