Trichomoniasis information

What is Trichomoniasis?


Trichomoniasis (trick-o-mon-I-AS-is) ⎼ sometimes called just "trich" (trick) ⎼ is a sexually transmitted disease (STD) caused by a small parasite called Trichomonas vaginalis.

According to the Centers for Disease Control and Prevention (CDC), there are about 7.4 million new cases of trichomoniasis in the United States each year. In fact, it's the most common curable STD among young women who are sexually active, although it's also found in men.

Trich typically infects the vagina in women, and the urethra (the tube that carries urine and semen out of the body) in men. Both men and women can catch trich by having unprotected penis-vagina intercourse with an infected partner. Women are also at risk for trich from an infected female partner through vulva-to-vulva contact...but men rarely contract the parasite from other men.

What are the signs and symptoms of trichomoniasis?

Most men and up to 85% of women with trich don't know they're infected. However, symptoms may include...

In women:

  • White or off-color vaginal discharge with a foul odor
  • Genital itching or redness
  • Pain during sex or urination
  • Frequent urination

In men:

  • Slight discharge from the penis
  • Mild burning sensation after urination or ejaculation

What are the risks and complications of trichomoniasis?

While it's possible to get infected through a first sexual experience, the risk of contracting trich increases among people who have multiple sex partners, and people who have had trich or other STDs in the past.

What about complications from trichomoniasis? If a woman with trich has unprotected sex with an HIV-positive partner, she's at a greater risk for contracting HIV. Additionally, HIV-positive women with trich may also be more likely to pass HIV to a partner.

Pregnant women with untreated trichomoniasis are at risk for pre-term delivery, and/or delivering a low-birth-weight baby. Without treatment, there's also a chance of an infected mother passing trich to her baby during delivery.

Men with a trich infection rarely experience complications.

Is there a test for trichomoniasis?

Yes, but mainly for women.

In women, diagnosis includes a pelvic exam to look at the vagina and cervix. The doctor will also take a small sample of vaginal fluid to be viewed under a microscope, revealing whether the parasite that causes trichomoniasis is present.

Trich is harder to diagnose in men. But a man may be treated if his partner has trich, or if he complains of burning in the urethra even after being treated for other STDs with similar symptoms (like chlamydia and gonorrhea).

Note: While a new technology enables trich testing on urine samples, it's not yet widely available.

Is trichomoniasis curable?

Yes, trich can often be cured with a single oral dose of either Metronidazole or Tinidazole*...your doctor can determine the correct dosage based on your individual circumstances.

If you have trichomoniasis, it's important that your sexual partner is treated at the same time. When one partner is diagnosed, a doctor may send home an extra dose of medication for the other person to take, as well.

A good rule of thumb for couples where one or both partners have trich: don't have sex for one full week after treatment to allow the medication to work, and to avoid passing the infection back and forth during sex.

*Note: These medications can cause nausea or vomiting if taken with alcohol. Follow your doctor's instructions, and avoid drinking alcohol for 24 hours after taking Metronidazole, and for 72 hours after taking Tinidazole.

Is trichomoniasis preventable?

There's no vaccine for trich, and it's possible to get re-infected if you've had it before.

But, as with most STDs, you can reduce your risk by practicing safer sex. Using condoms and limiting the number of sexual partners is always a good idea, and using spermicides (like Nonoxynol-9) can also reduce the risk of spreading trichomoniasis.

Primary Sources

Lisa Oldson, MD

STD expert

"The first thing I tell a patient about STDs is that if you're worried about one STD, you should probably worry about all STDs. In other words, if you had unprotected sex and you're worried about a possible HIV exposure, it's important to understand that hepatitis can be spread in the same fashion...ditto for chlamydia, gonorrhea, herpes and syphilis."