Trichomoniasis — CDC Fact Sheet

In brief

• Trichomoniasis ("trich") is a common, treatable sexually transmitted infection (STI).
• Most people who have it have no symptoms.

What it is

Trich is caused by infection with Trichomonas vaginalis, a protozoan parasite. CDC estimates there were more than two million infections in the United States in 2018. It is more common in women than men, and older women are more likely than younger women to have it.

Symptoms

About 70 percent of infected people have no signs or symptoms. When there are symptoms, they range from mild irritation to severe inflammation. Some people notice them 5 to 28 days after infection, others much later, and they can come and go.

Trich can make sex unpleasant. Without treatment, the infection can last for months or even years.

Complications

• Other STIs. Trich raises the risk of getting or passing on other STIs; the genital inflammation it causes, for example, makes it easier to get HIV or pass it to a partner.
• Pregnancy. Pregnant women with trich are more likely to deliver early, and their babies more likely to be born at low birth weight — under 5.5 pounds.

How it spreads

Trich spreads through sex without a condom with an infected partner. In women it is usually found in the lower genital tract (vulva, vagina, cervix or urethra); in men, inside the penis (the urethra). During sex it usually passes from penis to vagina or vagina to penis, and can pass from vagina to vagina. It rarely infects the hands, mouth or anus. Why some people get symptoms and others do not is unclear — probably factors such as age and general health. People without symptoms can still pass it on.

Prevention

The only way to avoid STIs completely is not to have vaginal, anal or oral sex. If you are sexually active:

• be in a long-term, mutually monogamous relationship with a partner who has tested negative for trich;
• use condoms correctly every time you have sex;
• talk about STI risk before having sex with a new partner;
• ask your health care provider whether you should be tested for trich or other STIs.

Diagnosis and treatment

Trich cannot be diagnosed from symptoms alone; a provider can examine you, and a lab test confirms it.

Trich is the most common curable STI. It is treated with medicine taken by mouth, which is also safe during pregnancy.

You can get it again after treatment: about 1 in 5 people are reinfected within 3 months, often through sex without a condom with an infected partner. To avoid that:

• your partners should be treated at the same time;
• do not have sex until you and your partners have finished treatment;
• get tested again about three months after treatment, even if your partners were treated.

Sources

• Centers for Disease Control and Prevention, Trichomoniasis – CDC Fact Sheet, drawing on the CDC's Sexually Transmitted Infections Treatment Guidelines, 2021 and national prevalence estimates for 2018. Its stock photo collage is left out.