Trichomoniasis (trih-ko-mo-NYE-uh-sis) is a common sexually transmitted disease (STD) that occurs in both women and men.


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Sexually transmitted diseases (STDs)

Trichomonas vaginalis

What Is Trichomoniasis?

Trichomoniasis (also known as "trich") is an infection caused by the parasite Trichomonas vaginalis (trih-koh-MO-nas vah-jih-NAL-is). It usually affects the urethra * in men and the vagina or urethra in women.

The disease spreads from person to person through sexual contact and infects primarily women between the ages of 16 and 35. It is one of the most common STDs in young sexually active women, and the U.S. Centers for Disease Control and Prevention says that about 2 million new cases occur in women each year in the United States. As with all STDs, people who have had many sexual partners are more likely to contract trichomoniasis.

What Are the Signs and Symptoms?

Women who contract trichomoniasis are more likely to have symptoms than men who become infected, although many people who have trichomoniasis experience no symptoms at all. If a person has symptoms, they usually appear within 6 months of becoming infected. Women often have a strong-smelling yellow-green or gray foamy vaginal discharge and itching in or around the vagina. Often, the discharge has a fishy odor. They may feel pain or burning during sex or urination and, rarely, lower abdominal * pain. Men typically have no symptoms. When they do, they may feel irritation inside the penis and burning after urination or ejaculation * . They may have a discharge from the penis as well.

* urethra (yoo-REE-thra) is the tube through which urine passes from the bladder to the outside of the body.

* abdominal (ab-DAH-mih-nul) refers to the area of the body below the ribs and above the hips that contains the stomach, intestines, and other organs.

* ejaculation (e-jah-kyoo-LAY-shun) is the discharge of semen, a whitish fluid containing sperm, from the penis.

* pelvic exam is an internal examination of a woman's reproductive organs.

* cervix (SIR-viks) is the lower, narrow end of the uterus that opens into the vagina.

How Do Doctors Diagnose Trichomoniasis?

If a woman has symptoms of the disease, the doctor will perform a pelvic exam * to look for the tell-tale signs of inflammation on the cervix * and

A magnification of Trichomonas vaginalis, the parasite that causes trichomoniasis. Infection occurs in both men and women, but women have symptoms more often then men have symptoms. ©D.M. Phillips/Visuals Unlimited
A magnification of Trichomonas vaginalis, the parasite that causes trichomoniasis. Infection occurs in both men and women, but women have symptoms more often then men have symptoms.
©D.M. Phillips/Visuals Unlimited
inner walls of the vagina. The doctor will take a sample of fluid from the vagina to look at under the microscope for evidence of the parasite. In some instances, Trichomonas infection may be found during a routine Pap smear * or when vaginal fluid is cultured * to diagnose infection caused by other organisms. Most cases of trichomoniasis that cause symptoms can be diagnosed in the doctor's office by examining the vaginal fluid under a microscope.

When trichomoniasis is suspected in a man, the doctor may take a sample of fluid from the man's urethra to confirm the diagnosis. If the doctor diagnoses trichomoniasis in any patient, tests for other STDs likely will be done as well, because it is common for a person to have more than one STD at the same time.

What Is the Treatment for Trichomoniasis?

Trichomoniasis is treated easily with antibiotics. Oral (by mouth) medication given over 1 week usually cures the disease. Doctors recommend that people who are infected not have sex until they have completed treatment, to limit the risk of spreading the infection. Treating all sexual partners of someone who has trichomoniasis, even if they have no symptoms, also is suggested as a way to prevent a new round of infection or the spread of the disease.

Does the Disease Have Complications?

In a pregnant woman, the infection can bring about early rupture of the amniotic sac * and premature delivery * . Trichomoniasis also may increase the risk of becoming infected with human immunodeficiency (ih-myoo-no-dih-FIH-shen-see) virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS), which severely weakens the immune system.

Can Trichomoniasis Be Prevented?

The risk of trichomonas infection can be lowered or prevented by:

  • practicing abstinence (not having sex)
  • practicing safe sex by using a male latex condom
  • reducing the number of sexual partners

* Pap smear is a common diagnostic test used to look for cancerous cells in the tissue of the cervix.

* cultured (KUL-churd) means subjected to a test in which a sample of fluid or tissue from the body is placed in a dish containing material that supports the growth of certain organisms. Typically, within days the organisms will grow and can be identified.

* amniotic sac (am-nee-AH-tik SAK) is the sac formed by the amnion, the thin but tough membrane that lines the outside of the embryo in the uterus and is filled with fluid to cushion and protect the embryo as it grows.

* premature delivery is when a baby is born before it has reached full term.



U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC runs the National STD and AIDS Hotline to answer questions about sexually transmitted diseases and provide referrals to doctors. It also offers information on trichomoniasis on its website.
Telephone 800-311-3435
Hotline 800-227-8922

Website . KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children's health. It contains articles on a variety of health topics, including trichomoniasis.

See also
AIDS and HIV Infection
Chiamydial Infections
Sexually Transmitted Diseases

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