Sexually transmitted infections (STIs) are a rising public health concern. There are more than 1 million cases of STIs occurring every day across the globe and one such disease is called trichomoniasis. Trichomoniasis is a common, non-viral, sexually transmitted infection caused by the parasite Trichomonas vaginalis. It is spread during sexual contact through vaginal fluids and semen.1
Trichomoniasis is easily transmitted as people often show no symptoms when infected. However, there are ways to limit its spread which this article explains, as well as everything else you need to know about trichomoniasis.
Causes of trichomoniasis
A parasite called Trichomonas vaginalis causes trichomoniasis. It infects the squamous epithelial cells (found on the outer layer) of the genitals. It then attaches itself to these cells via special proteins and continues to grow there.1,2
The main sites of trichomonas infection in people assigned female at birth (AFAB) are the vagina and the urethra. It can also be found in the cervix, bladder, Bartholin’s glands, and endocervix (inner part of the cervix). In people assigned male at birth (AMAB), the common site of infection is the urethra,but it is also seen in the epididymis.2
Trichomonas can also infect the anus, mouth, and hands in both people AFAB and AMAB. It thrives in an anaerobic (without oxygen) and alkaline environment (pH greater than 7). The parasite cannot survive outside the human body but it can stay alive in a wet environment for more than 3 hours.1,2
Trichomoniasis is transmitted through:
- Vaginal sex (Vaginal-penile or vaginal-vaginal sexual intercourse)
- Anal sex
- Oral sex
- Genital contact (skin-to-skin contact without ejaculation)
Asymptomatic people (those who show no symptoms) spread the disease unknowingly to their sexual partners. It’s estimated that more than 70% of partners that are AMAB get infected after contact with infected people AFAB.2
Trichomonas cannot be spread through:2
- Sharing food and drinks
- Non-sexual contact (holding hands)
- Toilet seats
- Wet towels
- Hot tubs
Trichomoniasis is not caused by poor hygiene or UTIs (Urinary tract infections). However, it can be triggered by vaginal irritation due to:2
- Oral contraceptives (birth control pills)
- Hormone therapy
- Tight-fitting clothes
- Sex without lubrication
- Cuts or wounds on the vagina
Signs and symptoms of trichomoniasis
The main reason trichomonas spreads easily is that most patients are asymptomatic. However, symptoms develop over time in some cases. They usually appear within 5-28 days of infection and differ in people AFAB and AMAB.2
People AMAB rarely experience symptoms of trichomoniasis but in those that do, the common symptoms are:
- Frothy penile discharge
- Penile itching or irritation
- Pain during urination or intercourse
- Burning sensation after ejaculation or during urination
Trichomoniasis symptoms are more common in people AFAB and they include:1,4
- A large amount of thin or foamy, foul-smelling vaginal discharge (either clear, white, grey, yellow, or green in colour)
- Vulvar and vaginal irritation, soreness, redness, or burning.
- Strawberry cervix (seen in 2-5% of patients)
- Pain during intercourse or urination.
- Abdominal pain
People AFAB can also experience cyclic symptoms that worsen during menstruation.7
Management and treatment for trichomoniasis
Trichomoniasis will not go away on its own. Without treatment, the infection can linger on for months or even years. Trichomoniasis is treated with oral antibiotics that kill the parasite and can be given while pregnant. Healthcare providers will prescribe either metronidazole, tinidazole, or secnidazole.1,3
Treatment options for trichomoniasis include:
- Megadose: A single large dose of one of the above antibiotics to be taken only once
- Multiple doses: Many lower doses of one of the above antibiotics to be taken twice a day for seven days. Take the full course of the medication even if the symptoms clear up. Stopping the medication early will not cure the infection
Longer courses or more doses of these medications are prescribed for persistent and recurring infections. Healthcare providers will retest patients for trichomoniasis two weeks to 3 months after treatment to ensure the infection is completely gone.3
Precautions of trichomonas treatment
Some precautions that are important to abide by are:2
- Refrain from having sex for one week after treatment to avoid reinfection
- Do not consume alcohol or alcoholic beverages during treatment and a few days after the last dose since it causes rapid heart rate and severe nausea and vomiting
- Stop breastfeeding during the treatment and 3 days after the last dose to avoid exposing your baby to these medications
- Report the following allergic reactions or hypersensitivity symptoms to your doctor immediately if they occur:
- Facial oedema
- Anaphylactic shock
- These medications can cause heartburn and leave a metallic taste in your mouth. So, report any side effects if they occur
Partner Treatment/ Partner Therapy
Sexual partners of people infected with trichomoniasis should get treated for the infection and other STIs simultaneously to prevent reinfection. EPT (Expedited Partner Therapy) is a CDC-recommended partner therapy that involves providing prescriptions to the sex partners of infected patients without clinically assessing them.3
Diagnosis of trichomoniasis
Healthcare providers diagnose trichomoniasis by performing the following tests:
- Physical exam: Your healthcare provider examines your genitals and assesses the symptoms you’re experiencing. For people who are AFAB this may include a pelvic exam and a sample of vaginal discharge and for people who are AMAB this will involve a sample of penile discharge.
- Lab Tests: These tests detect trichomonas in a sample of vaginal fluid or a penis urethral swab and the various types are listed below.2,3,4
The sample is examined under the microscope to check for trichomonas infection. If the parasite is seen, no more tests are needed. However, if trichomoniasis is not detected, other tests are done.
The sample is placed in a culture medium and examined after 2-7 days. If trichomoniasis is present in the sample, the parasite will multiply in the medium.
It detects and identifies Candida (yeast) species, Gardnerella vaginalis, and Trichomonas vaginalis in one vaginal sample. It has a high sensitivity for Trichomonas vaginalis and provides results in 45 minutes.
Rapid antigen test
It detects trichomonas antigens (proteins that trigger the immune system to produce antibodies) in a sample of vaginal fluid. The test can be done in a doctor’s office and the results are provided in 10-15 minutes.
Nucleic acid amplification test (NAAT)/RT-PCR test
It’s a highly-sensitive test that detects genetic sequences of trichomonas. It works on various sample types forms, including urine, vaginal fluid, and cervical discharge.
- Other diagnostic tests include:the potassium hydroxide (KOH) “Whiff test”, vaginal pH test, and pap smear.
Your healthcare provider may also perform tests for other STIs.2
The risk factors that predispose an individual to get trichomoniasis are:2
- Old age
- Multiple sexual partners
- Unprotected sex
- Previous history of STIs
- Concomitant infections
- Non-Hispanic black ethnicity
- Low socioeconomic status
- Low education level
- People AFAB are more prone to trichomoniasis than AMAB
Untreated trichomoniasis results in various complications which are listed below.1,2
Complications of trichomoniasis in people who are AFAB
- HIV: Trichomoniasis increases the risk of contracting HIV by exposing the target cells of HIV, i.e. white blood cells and causing infections that increase its risk by disrupting the normal vaginal microbiome.
- Altered reproductive health and pregnancy: Trichomoniasis causes infertility, premature labour and delivery, low birth weight babies, premature rupturing of placental membranes, and neonatal death.
- Cervical cancer: Trichomonas vaginalis increases the risk of developing HPV -induced cervical cancer by 2-fold.
- Pelvic inflammatory disease: The incidence of pelvic inflammatory disease is higher in people infected with trichomonas than those that are not.
- HSV2: there is a higher chance of contracting Herpes Simplex virus II when infected with Trichomonas vaginalis.
Complications of trichomoniasis in people who are AMAB
- HIV: There’s a 6-fold increase in HIV concentration in people AMAB with trichomonas than those without it.
- Altered reproductive health: Trichomonas causes infertility by significantly decreasing sperm motility and viability.
How can I prevent trichomoniasis?
The ways to prevent trichomoniasis if you are sexually active include:2,3,4
- Use condoms correctly during sexual intercourse and avoid oil-based lubricants as they can cause latex condoms to break
- Always be aware of your partner’s sexual history and share yours with them
- Ensure you and your partner undergo regular testing for trichomoniasis and other STIs. People who are AFAB with and without HIV should get tested at least once a year
- Get your partner and yourself treated when infected with trichomoniasis or any other STIs
- Limit the number of sexual partners or stick to a long-term monogamous relationship with one partner
- Use microbicides before sex which prevent trichomonas from attaching itself to the cells of the genital tract
- Circumcision also prevents trichomoniasis. Some studies have shown that partners of circumcised people AMAB have lower chances of getting the disease and other infections.
How common is trichomoniasis?
It mainly affects people AFAB, but people AMAB can also contract it. Among people AFAB, trichomonas infections are mostly seen in those 35-40 years old and those with black ethnicity. Trichomoniasis is most prevalent in Africa and the US compared to the UK.3,4,
Is trichomoniasis contagious?
Trichomoniasis is contagious and is spread through sexual contact. Most people unknowingly transmit this infection to their sexual partners as there are no symptoms most of the time.
When should I see a doctor?
You should see a doctor if:1,3
- You experience the following symptoms –
- Foul-smelling or frothy vaginal and penile discharge
- Painful urination or intercourse
- Genital itching, irritation, redness, or burning
- You still have symptoms after treatment
- You are sensitive or allergic to the oral antibiotics prescribed
Trichomoniasis is a common, curable, non-viral sexually transmitted disease caused by the parasite Trichomonas vaginalis. Patients infected with trichomonas often show no symptoms and unknowingly infect their partners. Hence, the patient and partner should get treated and tested simultaneously to stop the infection. Trichomoniasis requires oral antibiotics to kill the parasite. Leaving it untreated causes serious complications. You can prevent trichomoniasis by practising safe sex and undergoing regular testing. It’s also always best to contact your doctor if you notice any strange changes in your genitals.
- Kissinger P. Trichomonas vaginalis: a review of epidemiologic, clinical and treatment issues. BMC Infect Dis [Internet]. 2015 Dec [cited 2023 May 15];15(1):307. Available from: http://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-015-1055-0
- Ifeanyi OE, Chinedum OK, Chijioke UO. Trichomonas vaginalis: complications and treatment. Int J Curr Res Med Sci [Internet]. 2018 [cited 2023 May 15];4(5):76-89. Available from: https://researchgate.net/Trichomonas vaginalis: Complications and treatment
- Van Gerwen OT, Muzny CA. Recent advances in the epidemiology, diagnosis, and management of Trichomonas vaginalis infection. F1000Research [Internet]. 2019 [cited 2023 May 15];8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6758837/
- Bouchemal K, Bories C, Loiseau PM. Strategies for prevention and treatment of Trichomonas vaginalis infections. Clinical microbiology reviews [Internet]. 2017 July [cited 2023 May 15] ;30(3):811-25. Available from: https://journals.asm.org/doi/full/10.1128/CMR.00109-16