Trichomoniasis [trik-uh-muh-naya-sis], or “trich,” is a sexually transmitted infection (STI) that is spread through skin-to-skin contact during vaginal, oral, or anal sex. The infection is treatable and can be cured with antibiotics.
The microscopic parasite Trichomonas vaginalis causes trichomoniasis, and thus it is different than many other STIs because it is not caused by a virus or a bacterium.

This STI is the most common curable one among young women who are sexually active. Estimations place the number of new cases each year in the USA at 7.4 million. Only about 30% of infected people present any symptoms.

What are the symptoms of Trichomoniasis?

Though most people who have it do not show any signs, some possible symptoms include:

  • Itching or burning sensation in the genitals
  • Soreness or redness of the genitals
  • Burning sensation during urination
  • The unpleasant feeling during sexual intercourse
  • Men: discharge from the penis
  • Women: change in vaginal discharge with a foul odor (color can be white, gray, yellow, or greenish)

Symptoms may come and go and can show up as early as 5 to 28 days after sexual contact and can range from mild to severe. Call your doctor if you experience any of these symptoms.

Can trichomoniasis lead to other problems?

Yes, it can. Without proper treatment, a trichomoniasis infection can make you more susceptible to getting or transmitting other STIs, such as HIV (the virus that leads to AIDS). This is especially true if you are experiencing symptoms of trichomoniasis.

How is it transmitted?

Trichomoniasis is passed along through skin-to-skin contact during sexual acts such as vaginal, anal, or oral sex. This means that a condom may not protect a person completely since the parasite may be on parts of the skin that are not protected by a condom.
Though rare, a pregnant woman with an active trichomoniasis infection can pass it on to her baby during birth.
People who have trichomoniasis but do not have symptoms can still pass it on to their sexual partners.

Who is at risk?

You are at a higher risk for contracting trichomoniasis if you:

  • know that your partner is infected
  • have multiple sexual partners
  • have sex without condoms
  • have/had other STIs, or
  • have had a previous trichomoniasis infection.

Young, sexually active women under 25 years old have the highest rates of trichomoniasis infections.

How can trichomoniasis affect my pregnancy?

If a trichomoniasis infection is left untreated during pregnancy, it can increase a woman’s chances of pre-term delivery and low birth weight. Both of these can affect the baby’s development, overall health, and time spent in the hospital after birth.

There is also a chance that the infection/parasites could be transmitted to the baby during vaginal birth. This is, however, very rare and the infant is usually easily cured with antibiotics. Possible other adverse outcomes are possible if the infection is left untreated.

To learn more about how trichomoniasis can affect your pregnancy, check out our article Trichomoniasis During Pregnancy.

How is it diagnosed and treated?

Trichomoniasis is diagnosed not through symptoms, but through an exam by your doctor and a laboratory test.
The treatment is a large single dose of antibiotics, typically metronidazole or tinidazole. Common brand names for these are Flagyl or Tindamax. If both you and your partner test positive, it is suggested that both of you undergo the antibiotic treatment at the same time. This is important if you want to avoid passing it back and forth.

Can trichomoniasis be prevented?

There are only two effective ways to prevent it. The first is to refrain from sexual contact of any kind. The second is to be in a long-term monogamous relationship such as marriage with someone who is not infected. It is extremely rare that casual contact (no sexual contact) can transfer the parasite.

Since this STI can be spread through skin-to-skin contact and does not require the sharing of bodily fluids, condoms are not a reliable method for preventing infection. The correct and consistent use of condoms may only help reduce the chance of passing on or contracting trichomoniasis.

Want to Know More?

Compiled using information from the following sources:

1. Centers for Disease Control and Prevention (CDC) – Trichomoniasis Fact Sheet.

2. Sexuality Information and Education Council of the United States (SIECUS) – STD Fact Sheets.

3. Mayo Clinic – Diseases and Conditions: Trichomoniasis.