Trichomoniasis (trick-oh-mo-NEYE-ah-sis), or “trich,” is an infection in the vagina or the male urethra and prostate gland caused by the microscopic, single-celled protozoan called Trichomonas vaginalis.1 While this protozoan can affect both males and females, it typically affects females more. About 3.7 million people have the infection in the United States, while only 30% ever develop symptoms.2 The good news is that trichomoniasis is the most common curable STI! 2


Trichomoniasis is spread through sexual contact. The vulva, vagina, and urethra are the most common sites of infection in females, while the urethra is the paramount site of infection in males. During any sexual activity involving one’s genitals, the protozoa are able to spread. Even mutual masturbation can lead to transmission if fluid exchange occurs. Trichomoniasis can survive on objects such as towels, underwear, or sex toys. For this reason, sharing sex toys and other potentially infected objects may lead to the spread of the infection. Contraception should be used when participating in vaginal and anal sex or mutual masturbation in order to avoid transmission of trichomoniasis. Abstinence is the most effective method of preventing STIs but if you are sexually active, we recommend barrier methods of contraception such as latex condoms, which are the most effective against prevention of STIs. Although condoms are not 100% effective at protecting against STIs, they are the best methods of prevention. The protozoa do not usually infect areas outside of the reproductive tract, such as the mouth or hands.

Open and effective communication between both partners can lead to healthier sex lives. Getting tested frequently is important for anyone that is sexually active. If transmission does occur, infected individuals should avoid sexual contact with others and should immediately seek treatment from a health care professional along with any partners in contact.


Trichomoniasis is often asymptomatic, meaning the infection shows no signs of being present. An incubation period of 5 to 28 days is standard, so if symptoms do develop, they will likely not appear for several weeks. Females who eventually develop symptoms may not notice any for up to six months! At any given moment, roughly 3% of reproductive-aged females in the U.S. are infected with “trich.”1 Even more staggering, approximately a quarter of all vaginitis cases (inflammation of the vagina) are due to the Trichomonas protozoan. 2

Trichomoniasis can have display different symptoms in males and females. The listed symptoms below are some of the most common symptoms that appear in infected individuals.

Symptoms in Females 

  • Foul-smelling, greenish, or frothy vaginal discharge
  • Blood spotting in vaginal discharge
  • Vaginal itching and redness
  • Swelling in the groin
  • Painful sexual intercourse
  • Frequent urge to urinate—often accompanied by pain and burning2

Symptoms in Males

  • Urethral discharge
  • Frequent urge to urinate—accompanied by pain and burning2

Symptoms in males and females may differ significantly. It is very important to distinguish the different symptoms. Additionally, it is critical to recognize symptoms so that a healthcare professional can be informed and proper treatment can be provided.


Trichomoniasis is diagnosed by microscopic examination of fluid taken from a swab of the afflicted vagina or urethra. In some cases, the diagnostic procedure includes creating a culture from the gathered specimens. Keep in mind that when recognizing symptoms, it is important to avoid self-diagnosing since only a trained healthcare professional can confirm the diagnosis with a microscopic examination. Furthermore, self-diagnosing can lead to unnecessary anxiety about an infection that may not even be present. Always seek the advice of a healthcare professional if any concerns arise.


Trichomoniasis can be cured with an oral dose of metronidazole or tinidazole. These medications should NOT be used during pregnancy because extensive research related to the effects of these drugs on unborn children have not been conducted. Further, the U.S. food and drug administration classify metronidazole as a Type B drug, meaning it may cause bizarre side effects and, thus, should only be taken when necessary. 2 Simultaneous treatment should be administered to prevent partners from swapping the infection between each other. One in five patients who are treated become infected again after treatment so following up with a doctor is important. 2

While the symptoms of trichomoniasis might seem more annoying than dangerous, if left untreated, there can be serious consequences. The genital inflammation caused by “trich” can make infected individuals more susceptible to the HIV. Furthermore, trichomoniasis can have negative impacts on pregnancy as it can lead to premature delivery and low birth weight.2 The infection weakens the membranes surrounding the amniotic sack, eventually rupturing it, and thus, starting premature labor. Overall, treatment for trichomoniasis is fairly simple and extremely effective at curing the infection as well as preventing further health problems from arising.2 Overall, treatment for trichomoniasis is fairly simple and extremely effective at curing the infection as well as preventing further health problems from arising.

Concluding Remarks

Trichomoniasis is an easily curable infection with very effective treatments, but the prevalence of the infection is still extremely high so it should be taken very seriously. The symptoms range from swelling of the groin to premature labor so identification of the infection is very important for treatment. Furthermore, if reduced risk of infection is desired, use barrier protection methods such as male condoms can be used to used to protect sexually active individuals from trichomoniasis and other STIs. Remember to never self-diagnose and to consult health care professionals for proper diagnosis and treatment. For STIs, remember to never self-diagnose and to consult health care professionals for proper diagnosis and treatment. If risky sexual behavior occurs, contact a health care professional immediately and get tested.


  1. LeVay, Simon, Janice I. Baldwin, and John D. Baldwin. Discovering Human Sexuality. Sunderland, MA: Sinauer Associates, 2009. Print.
  2. “Trichomoniasis – CDC Fact Sheet.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 31 Jan. 2017. Web. 28 Feb. 2017.
  3. “Trichomoniasis.” Trichomoniasis. STD-Gov., n.d. Web. 22 Apr. 2014.

Last Updated: 12 March 2017.