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Sex

Trichomoniasis 101

by Nicole Telfer, Science Content Producer
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Top things to know

  • Trichomoniasis is often asymptomatic, meaning that many people don’t know they have it
  • Some people may experience symptoms including increased, malodorous, colored vaginal discharge, vulvar pain and itchiness, and/or pain with urination or sexual intercourse

What is trichomoniasis?

Trichomoniasis is a very common sexually transmitted infection (STI) that is caused by the parasite Trichomonas vaginalis. Although not as commonly discussed as other more “famous” STIs (like HIV, gonorrhea, chlamydia), trichomoniasis is actually estimated to be the most common non-viral STI in the United States (1).

Huh? How can trichomoniasis be so common, and I’ve never even heard of it? I thought chlamydia and gonorrhea were the most common STIs?

Not quite. In the United States, trichomoniasis is not required to be reported to the Centers for Disease Control (CDC). Currently, Trichomonas vaginalis infections are not considered reportable conditions because of the low severity of health outcomes, the low cost associated with treatment, difficulty in prevention, and low public interest/concern (2).

The most prevalent STI in the United States is estimated to be human papillomavirus (HPV), followed by genital herpes (HSV-2), both of which are not reported diseases to the CDC (1). Trichomoniasis comes in next, estimated to be the third most-prevalent STI in the United States (1). This is why chlamydia and gonorrhea are the most common reported STIs in the US, and trichomoniasis is the most common non-viral STI. These small words make a huge difference when understanding disease prevalence across the country.

What are the symptoms of trichomoniasis?

Trichomonas vaginalis commonly infects the vagina, urethra, or cervix in women and people with female reproductive tracts (3). In men and people with male reproductive tracts, the urethra is the most common site of infection (3).

It is difficult for many people to realise they have a trichomoniasis infection, since 70% are asymptomatic—this means they do not have physical signs or symptoms of the infection (3). Some women and people with female reproductive tracts may experience symptoms such as changes in vaginal discharge, which can change color to yellow-green-gray, become frothy, copious, and/or develop an unpleasant foul or fishy odor (4). Some people may also experience itching, burning or redness of the vulva and/or pain during urination or sex (4). The symptoms may be made worse during menstruation (5).

These symptoms may not be constant, but may come and go over time (3,4). Some people develop symptoms a couple of days after infection, while others may only notices symptom changes much later (3).

Men with trichomoniasis often also do not experience symptoms, but if they do notice symptoms these can include itchiness or irritation of inside the penis, a burning sensation after urination or ejaculation, and/or discharge from the penis (3).

How does one get trichomoniasis?

Trichomoniasis is spread through penis-vagina sex and vulva-vulva sex. Anal sex or oral sex are not common routes of Trichomonas vaginalis transmission (3). It has been suggested that it may also be spread via contact with objects (like shared washcloths after sex) or mutual masturbation with fingers, but this type of disease transmission is not very common (6,7).

People of all genders can contract trichomoniasis from heterosexual sex, but transmission between men during homosexual sex is much lower (8).

A person can also be re-infected with trichomoniasis after having been treated previously. People don’t become immune to trichomoniasis after they’ve had it (3).

How common is trichomoniasis?

It is estimated that trichomoniasis is the third most prevalent STI in the United States, affecting around 3.7 million people (1).

Worldwide, the World Health Organization (WHO) estimates that in 2008 there were 276.4 million cases of adults infected with Trichomonas vaginalis (9). This estimate is greater than the WHO’s estimates for all the cases of chlamydia, gonorrhea, and syphilis combined (9).

How can I prevent contracting trichomoniasis?

Being sexually active puts people at risk for contracting an STI. Using condoms during every sex act can greatly reduce the risk of contracting trichomoniasis (and many other STIs). Condoms should be used not just during ejaculation, but before any genital or sexual contact starts.

Ask all partners whether they’ve been tested recently for STIs before starting sexual contact. If a partner has sex with multiple people, ask about their STI status and encourage them to also get tested. Limiting the number of sexual partners you are exposed to will also decrease your risk of contracting trichomoniasis and other STIs.

If unprotected sex has occurred, or if symptoms of a trichomoniasis infection are present, visit your healthcare provider or local STI clinic for screening tests.

In addition, practices like douching should be avoided, as this may actually increase chances of contracting an STI (10).

How is trichomoniasis treated?

Getting tested for trichomoniasis can be done with either a urine sample or vaginal swab. After getting a diagnosis, it is important that sexual partners also be treated, in order to prevent reinfection (11).

Trichomoniasis can be quickly treated using a medication with both antibiotic and antiprotozoal functions (11). When taking these medications, it is important to abstain from alcohol ingestion for 24-72 hours, as this can cause negative interactions (11). It is possible to transmit trichomoniasis even while being treated. Stay away from sexual contact for at least 7-10 days until after completion of the full course of medication—even if symptoms have already gone away (3,11).

A follow-up appointment should be scheduled three months after treatment (11). Antimicrobial resistance is possible with trichomoniasis infections, so if symptoms persist after treatment, be sure to follow-up sooner with your healthcare provider (11).

What are the potential complications of trichomoniasis?

In pregnant people, untreated trichomoniasis infections can result in preterm delivery and low birth weight babies (3,11). If you are pregnant and suspect your have trichomoniasis or are at risk of contracting the infection, speak to your healthcare provider about testing.

Having an STI, like trichomoniasis, can also increase your chances of contracting HIV if exposed to it, or spreading HIV if already infected (12-14). Also, people with trichomoniasis infections are at greater risk of developing pelvic inflammatory disease (PID) if they are HIV positive (15).

If you think you have trichomoniasis, or any STI, it is important for you to seek help from your healthcare provider or an STI clinic. Many clinics provide free or low-cost STI testing. This will all help keep you, your sexual partners, and your community healthy.

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