Trichomoniasis (or “trich”) is a very common STD caused by infection with Trichomonas vaginalis (a protozoan parasite). Although symptoms vary, most people who have trich cannot tell they have it.

As part of their lifecycles, some parasitic protozoa like Giardia can live in harsh environments as hardy cysts that can even survive in cold water for months. These can be found in contaminated water, food, or in feces.

In the United States, CDC estimates that there were more than two million trichomoniasis infections in 2018. However, only about 30% develop any symptoms of trich. Infection is more common in women than in men. Older women are more likely than younger women to have the infection.

In women, the infection is most commonly found in the lower genital tract (vulva, vagina, cervix, or urethra). In men, the infection is most commonly found inside the penis (urethra). During sex, the parasite usually spreads from a penis to a vagina, or from a vagina to a penis. It can also spread 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. It probably depends on factors like a person’s age and overall health. People with trich can pass the infection to others, even if they do not have symptoms.

Men with trich may notice:

Women with trich may notice:

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

Pregnant women with trich are more likely to have their babies early. Also, their babies are more likely to have a low birth weight (less than 5.5 pounds). Also, putting the baby at risk for infection to the baby as the baby passes through the birth canal.

If any woman suffers from trichomoniasis infection for a longtime or does not receive treatment within time, infection may result in variations in her cervix tissue. In this situation, when the respective woman has annual Pap smear, it will display abnormal cells. If the trich problem causes variations in cervical tissue, woman has to undergo treatment for the removal of abnormal cells. This can require undergoing with cryosurgery to freeze off the abnormal cell/tissue.

Trich is the most common curable STD. A healthcare provider can treat the infection with medication (pills) taken by mouth. This treatment is also safe for pregnant people.

If you receive and complete treatment for trich, you can still get it again. Reinfection occurs in about 1 in 5 people within 3 months after receiving treatment. This can happen if you have sex without a condom with a person who has trich. To avoid reinfection, your sex partners should receive treatment at the same time.

You should not have sex again until you and your sex partner(s) complete treatment. You should receive testing again about three months after your treatment, even if your sex partner(s) received treatment.
Treatment for trichomoniasis is taking an antibiotic — either metronidazole (Flagyl), tinidazole (Tindamax) or secnidazole (Solosec). To prevent being infected again, all sexual partners should be treated at the same time. You can reduce your risk of infection by using condoms correctly every time you have sex.

Risk factors for getting trichomoniasis include having: