What Is Trichomonas Vaginalis? Understanding the Parasite Behind Trichomoniasis

You’ve probably heard of sexually transmitted infections (STIs) like chlamydia and gonorrhea, but what about trich? Short for trichomoniasis, this common STI is caused by a parasite called Trichomonas vaginalis¹…and it’s way more widespread than most people think.

Because its symptoms often overlap with other vaginal infections like bacterial vaginosis or a yeast infection, trichomoniasis can easily go misdiagnosed, which is dangerous, since, left untreated, it can increase your risk of complications like pelvic inflammatory disease, low birth weight, and even other STIs.

Let’s get to know the parasite behind the infection, how trichomoniasis affects your body, and how to bounce back after an infection.

This post is for informational purposes only and does not constitute medical advice. See full disclaimer below.

What Is Trichomonas vaginalis?

Trichomonas vaginalis (or T. vaginalis) is a protozoan parasite that causes trichomoniasis, a sexually transmitted disease primarily spread through sexual intercourse². Unlike bacteria or viruses, this tiny organism moves with a whip-like tail, allowing it to migrate through the vaginal canal, urethra, or cervix (depending on who’s infected).

This parasite thrives in the urogenital tract and can live in both men and women, although it’s diagnosed far more often in women. The tricky part? Many infected people never show symptoms, which means T. vaginalis can silently spread from one sexual partner to another.

What Is Trichomoniasis?

Trichomoniasis, or "trich," is a sexually transmitted infection (STI) caused by the parasite Trichomonas vaginalis. In fact, it's one of the most common and the most underdiagnosed STIs here in the US. According to the Centers for Disease Control and Prevention (CDC), millions of Americans contract trich each year, but it is hard to get an exact number because many people who have trich remain asymptomatic (though they can still pass it to others).

When symptoms do show up, they can be hard to attribute to trich, at least initially, because they often resemble other infections like bacterial vaginosis, vaginitis, or candidiasis³.

The most common symptoms of trich include:

• Vaginal discharge that's thin, yellow-green, or frothy with a strong odor
  
• Itching or soreness around the vulva⁴
  
• Burning during urination or after sex⁵
  
• Redness of the cervix, sometimes referred to as "strawberry cervix"
  
• In men: discharge from the urethra, urethritis, or painful urination

Diagnosis: How Do You Know It’s Trich?

The only person who can diagnose Trich is a healthcare provider. They will do this by asking you about your symptoms, performing a pelvic exam, and then taking a vaginal swab⁶. They will use the swab to look for the parasite through a test like:

• Wet mount microscopy⁷
• Antigen test
  
• Nucleic acid amplification test (NAATs)

NAATs are the most sensitive of the three tests and the one recommended by the CDC for spotting Trich. 

Because Trich is often asymptomatic, it's important to get tested routinely (not just if you have symptoms). Trich is included in most standard STI tests. If you're sexually active, have a new sexual partner, or have multiple sexual partners, make STI testing a part of your annual exam.

Treatment for Trichomoniasis

While no one ever wishes for an STI, the good news is that trich is very treatable⁸. Most people are prescribed the antibiotic metronidazole or tinidazole, usually as a single dose or a brief course⁹. These antibiotics are part of the CDC’s treatment guidelines for sexually transmitted diseases.

During treatment your doctor may advise you to:

• Avoid alcohol for 24 hours after taking the meds
• Inform and treat all sex partners to avoid reinfection
• Practice safe sex (using condoms) until cleared
  

Complications from Untreated Trichomoniasis

Regular STI testing is crucial, especially for trich. Leaving even asymptomatic trich untreated can increase your risk of:

• Pelvic inflammatory disease (PID)
• Preterm delivery and low birth weight in pregnancy
• Greater susceptibility to HIV and other STIs
  

Persistent inflammation of the vagina and genital tract also compromises long-term reproductive health¹⁰.

Supporting Vaginal Health After Treatment

While antibiotics may help to clear an active Trich infection, they are not the end of your treatment journey. After any sort of antibiotic treatment, it's important to support your body and your vaginal microbiome to protect against future infections. 

See, antibiotics don't just wipe out the infection-causing bacteria; they actually wipe out all the bacteria living in your vagina, including healthy Lactobacillus bacteria¹¹. Daily probiotics, especially following antibiotic use, can help restore these bacteria levels and strengthen your natural immunity.

Happy V's Prebiotic + Probiotic contains clinically studied strains of Lactobacillus like L. acidophilus and L. rhamnosus, which have been shown to help restore balance, maintain vaginal pH, and defend against overgrowth of pathogens.

In preclinical testing, Happy V's probiotic blend also showed a reduction in harmful bacteria, including those that cause yeast infections and BV, two of the most common secondary infections following STI treatment.

Along with taking high-quality probiotics, you can also support your body by:

• Not douching, since this can worsen bacterial imbalances
  
• Wearing breathable, cotton underwear
  
• Using condoms or other barrier methods 
  
• Staying on top of regular STI screenings

When to See a Healthcare Provider

Any unusual vaginal symptoms, such as unusual vaginal discharge, itching, or burning all signal that your body needs some support. Also, if you have recently had sexual contact with someone who has Trich, make an appointment with your doctor to get tested, even if you don't have symptoms yet. A quick swab test will save you from developing symptoms or passing Trich to another partner.

Final Thoughts

It's hard to say how common Trichomoniasis even is because it often flies under the radar. But even asymptomatic Trich can lead to health issues down the road if left untreated, not to mention be passed to another partner. This is why routine STI testing is important for anyone who is sexually active.

When spotted, Trich is easily treated, and after treatment, daily probiotics and protective habits will keep it from coming back.

Keep the Conversation Going

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• Explore our supplements made to support your vaginal health, from cycle to season.
  

Disclaimer: This blog is for informational and educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Statements about supplements have not been evaluated by the Food and Drug Administration. For more information about trichomoniasis or other STIs, visit cdc.gov or speak to a licensed health care provider.