What is trichomoniasis?

Trichomoniasis (or “trich”) is a very common sexually transmitted disease (STD) that is caused by infection with a protozoan parasite called Trichomonas vaginalis. Although symptoms of the disease vary, most women and men who have the parasite cannot tell they are infected.

What causes trichomoniasis?

Trichomoniasis is caused by the single-celled protozoan parasite Trichomonas vaginalis. The vagina is the most common site of infection in women, and the urethra is the most common site of infection in men.

How do people get trichomoniasis?

The parasite is passed from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina or urethra), and in men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite is usually transmitted from a penis to a vagina, or from a vagina to a penis, but it can be passed from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth or anus. It is unclear why some people with the infection get symptoms while others do not, but it probably depends on factors like the person’s age and overall health. Infected people without symptoms can still pass the infection on to others.

What are the signs and symptoms of trichomoniasis?

About 70 percent of infected people do not have any signs or symptoms. When trichomoniasis does cause symptoms, they can range from mild irritation to severe inflammation. Some people with symptoms get them within 5 days to 28 days after being infected, but others do not develop symptoms until much later. Symptoms can come and go.

Men with trichomoniasis may feel itching or irritation inside the penis, burning after urination or ejaculation, or some discharge from the penis.

Women with trichomoniasis may notice itching, burning, redness or soreness of the genitals, discomfort with urination, or a thin discharge with an unusual smell that can be clear, white, yellowish or greenish.

Having trichomoniasis can make it feel unpleasant to have sex. Without treatment, the infection can last for months or even years.

When do symptoms appear?

Symptoms usually appear within 5 days to 28 days of exposure in women.

What are the complications of trichomoniasis?

Trichomoniasis can increase the risk of getting or spreading other sexually transmitted infections. For example, trichomoniasis can cause genital inflammation that makes it easier to get infected with the HIV virus, or to pass the HIV virus on to a sex partner.

How does trichomoniasis affect a pregnant woman and her baby?

Pregnant women with trichomoniasis are more likely to have their babies too early (preterm delivery). Also, babies born to infected mothers are more likely be of low birthweight (less than 5.5 pounds).

How is trichomoniasis diagnosed?

To diagnose trichomoniasis, a health care provider must perform a physical examination and laboratory test. In women, a pelvic examination can reveal small red ulcerations on the vaginal wall or cervix. Laboratory tests are performed on a sample of vaginal fluid or urethral fluid to look for the disease-causing parasite. The parasite is harder to detect in men than in women.

Who is at risk for trichomoniasis?

Any sexually active person can be infected with trichomoniasis.

What is the treatment for trichomoniasis?

Trichomoniasis can be cured with a single dose of prescription antibiotic medication (either metronidazole or tinidazole), pills which can be taken by mouth. It is okay for pregnant women to take this medication. Some people who drink alcohol within 24 hours after taking this kind of antibiotic can have uncomfortable side effects.

People who have been treated for trichomoniasis can get it again. About one in five people get infected again within three months after treatment. To avoid getting reinfected, make sure that all of your sex partners get treated, and wait to have sex again until all of your symptoms go away (about a week). Get checked again if your symptoms come back.

How can trichomoniasis be prevented?

Using latex condoms correctly every time you have sex will help reduce the risk of getting or spreading trichomoniasis. However, condoms don’t cover everything, and it is possible to get or spread this infection even when using a condom.

The only sure way to prevent sexually transmitted infections is to avoid having sex entirely. Another approach is to talk about these kinds of infections before you have sex with a new partner, so that you can make informed choices about the level of risk you are comfortable talking with your sex life.

If you or someone you know has questions about trichomoniasis or any other STD, especially with symptoms like unusual discharge, burning during urination, or a sore in the genital area, check in with a health care provider and get some answers.

Where can I get more information?

Illinois Department of Public Health

HIV/STD Hotline 800-243-2437 (TTY 800-782-0423)

U.S. Centers for Disease Control and Prevention (CDC)
CDC-INFO Hotline (7am-7pm Mon.-Fri. Closed Holidays)

STD information and referrals to STD Clinics
800-CDC-INFO (800-232-4636)
TTY: 888-232-6348
In English, en Español

CDC National Prevention Information Network (NPIN)
P.O. Box 6003
Rockville, MD 20849-6003
888-282-7681 Fax

American Social Health Association (ASHA)
P. O. Box 13827
Research Triangle Park, NC 27709-3827

May 2013

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Illinois Department of Public Health
535 West Jefferson Street
Springfield, Illinois 62761
Phone 217-782-4977
Fax 217-782-3987
TTY 800-547-0466
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