Trichomoniasis, which most people call “trich” (pronounced as “trick”), is among the most common curable sexually transmitted diseases. Most cases of this infection go unnoticed because most people who are infected aren’t aware of it.
However, it’s estimated that as many as 180 million new trich infections occur globally every year, and, according to the Centers for Disease Control and Prevention, about 3.7 million Americans have trich.
Learn more about this common STD, what symptoms to look out for, how the infection can make a person more susceptible to other STDs and why trich is easy to mistake for other health problems.
In This Section
- Trichomoniasis Symptoms
- Trichomoniasis Transmission
- Trichomoniasis Prevalence
- At-Risk Groups
- Trichomoniasis Complications
- Trichomoniasis & Pregnancy
- Trichomoniasis Testing
- Trichomoniasis Treatment
- Trichomoniasis Prevention
Fewer than 1 in 3 people who are infected with trich experience any symptoms of the infection. For those whose bodies do show obvious signs of trich, those symptoms generally appear within a week of becoming infected but could take up to a month to show up.
It’s estimated that women are more likely to be infected, and men who have trich are very unlikely to see any obvious physical signs. Common symptoms are similar between men and women, but there are some distinctions.
- Burning after urination or ejaculation
- Penile discharge
- Irritation or itching inside penis
- Discomfort when urinating
- Itching, burning, pain or redness of genitals
- Change in vaginal discharge, including color (clear, white, yellow, green), volume and smell (especially including strong fishy odor)
Trich symptoms can vary from so minor they aren’t noticed to extremely painful and irritating. And because many women who have trich symptoms may mistake the discharge and odor from their vaginas as another STD or even a yeast infection, most trich infections aren’t properly diagnosed.
The parasite Trichomonas vaginalis causes trich infections as it’s passed from person to person during intercourse or other sexual activities. The trich parasite is transmitted in bodily fluids like semen, pre-cum and vaginal fluids.
While it’s most often spread during vaginal intercourse, trich also can spread easily by the sharing of sex toys or even through contact with fingers or other body parts that are carrying infected bodily fluids.
For women, the most commonly infected body parts are in the lower genital tract; this includes the vulva, vagina, urethra and cervix. For men, the urethra is the most commonly infected body part.
In addition to spreading via sex toys and vaginal intercourse, it’s also possible to spread trich through vagina-to-vagina contact, and, while it’s considerably less common, trich also can infect the mouth or the anus. Also, sexual intercourse does not have to take place or be finished to completion for trich to be spread from person-to-person.
However, because the parasite lives only in bodily fluids like semen and vaginal fluid, less-intimate contact like kissing cannot cause the STD to be spread from an infected person to another.
About 3.7 million Americans have trich, according to the CDC, but the overall number of new cases varies, and because trich is not a federally notifiable STD like chlamydia or syphilis, it’s difficult to pinpoint exactly how many people have it at any given time.
One method for gauging a relative increase or decline in trich is to examine data on doctor visits. According to CDC data, about 222,000 women between the ages of 15 and 44 sought a doctor’s care for a trich infection in 2016, which represents a huge increase from the 2015 figure of 139,000. However, it’s important to remember that most people who are infected do not get tested, so the number of doctor visits is a mere fraction of the overall prevalence of the infection.
Trich infections by year*
* Initial visits to physicians, women between 15 and 44 only
Any person who has sex or engages in other sexual activity with another person is at risk of contracting and spreading trich, which remains the most common curable STD. However, there are lifestyle and demographic factors that can contribute to a higher risk of becoming infected with trich:
- Gender: Women are more likely than men to become infected with trich, though people of all genders are at risk.
- Sexual partners: The more sexual partners a person has, the more statistically likely they are to contract trich.
- Race: Black women have a statistically elevated rate of trich.
- Sexual habits: People who rarely use condoms or dental dams during sex are more likely to have trich.
About 3% of women between the ages of 14 and 49 are estimated to have trich, and as many as 1% of women who have trich have never had sexual intercourse. Studies have indicated that, likely owing to gaps in sexual education along racial lines, African-American women have a higher rate of trich.
Trich prevalence by ethnicity (women 14-49)
One of the leading complications involving trich is the frequency with which trich infections are confused for other health issues, such as other infections. For women whose bodies do show symptoms, one of the most common is discolored discharge that’s accompanied by a foul-smelling, fishy odor.
Other issues sometimes mistaken for trich include:
- Yeast infection, which often causes vaginal discharge
- Bacterial vaginosis, a common vaginal infection that is not sexually transmitted but can be caused in part by sexual activity
- Chlamydia and gonorrhea, two very common STDs that can cause unusual vaginal discharge
Symptoms of trich can come and go, but the infection does not resolve on its own. Complications from an untreated trich infection include an increased risk of contracting other STDs, such as HIV, or developing pelvic inflammatory disease, or PID, an infection that can impact a woman’s fertility.
STDs during pregnancy, including trich, can be very serious. Pregnant women with trich have higher rates of preterm delivery, and their babies are more likely to be of low birth weight, meaning they weigh less than 5.5 pounds. It’s rare though not impossible for babies to contract trich during pregnancy or childbirth, but those who do can be treated with antibiotics to cure the infection.
Most pregnant women who show no physical signs of trich do not need to undergo routine testing for the STD, but some women who are considered high risk may consider getting tested for trich along with other STDs at least once during their pregnancy.
Routine testing for trich is generally not recommended for the bulk of the public, though there are a few groups who would benefit from initial and possibly repeated testing:
- Incarcerated women
- Sex workers
- Women with multiple sexual partners
- Illicit drug users
- Women with a history of STDs
- Women with HIV
For people who believe they’ve been exposed to trich, are having symptoms or are in one of the groups at an elevated risk of contracting the infection, there are many options for getting diagnosed, including:
- Doctor’s office
- Pharmacy clinic
- Campus health clinic
- Community health clinics
- At-home test kits
- Urgent care center
- Planned Parenthood
A trich test usually involves a vaginal swab for women and a urine test for men.
Trich is the most common curable STD, and the infection is easily treated with antibiotics, such as metronidazole or tinidazole, usually a single dose. Depending on a person’s overall health status and physiology, a doctor may recommend a lower dose for a longer period.
Those undergoing treatment should refrain from any sexual activity for about 7-10 days to ensure their bodies are fully cured, and they should avoid alcohol for a few days to prevent a potentially unpleasant interaction.
As with any STD, the best treatment for trich is prevention. A successful treatment course does not prevent a person from becoming infected in the future, and, in fact, an estimated 1 in 5 people who have been treated for trich get the infection again within three months.
People who are sexually active, including any sexual contact that involves bodily fluids, can lower their risk of getting trich by using condoms or dental dams every time they have sex and ensuring that they only have sex within a monogamous relationship with a person who is not infected with trich or other STDs.
While trich is less scary than some other STDs, it still can lead to potentially serious consequences, including pelvic inflammatory disease, which can impact a woman’s chances of having a baby when she decides the time is right for her. Even in the short term, trich infections are unpleasant and uncomfortable, but using safer sex practices and, if you need to, getting tested and treated can help you avoid this common infection.
- Centers for Disease Control and Prevention, 2015 STD Treatment Guidelines, Screening Recommendations and Considerations Referenced in Treatment Guidelines and Original Sources. (2015.) Retrieved from https://www.cdc.gov/std/tg2015/screening-recommendations.htm
- Centers for Disease Control and Prevention, Sexually Transmitted Disease Surveillance 2018, Table 44. Selected STDs and Complications — Initial Visits to Physicians' Offices, National Disease and Therapeutic Index (NDTI), United States, 1966-2016. (2019.) Retrieved from https://www.cdc.gov/std/stats18/tables/44.htm
- Centers for Disease Control and Prevention, Trichomoniasis-CDC Fact Sheet. (2017.) Retrieved from https://www.cdc.gov/std/trichomonas/stdfact-trichomoniasis.htm