Trichomoniasis (Trich): Causes and Symptoms
Disclaimer: Not medical or professional advice. Always seek the advice of your physician.
Trichomoniasis (Trich) is a sexually transmitted infection caused by the protozoan Trichomonas vaginalis. The infection does not go away on its own, so it must be treated. The WHO estimates an incidence of around 250 million cases of trichomoniasis each year. Women are more likely than men to get the disease.
Trichomonas vaginalis, a single-celled protozoan parasite, is the etiologic agent of trichomoniasis. It can move with the aid of flagella.
When was Trichomoniasis First Diagnosed?
- Alfred Francois Donné, a professor of microscopy at the Collège de France, while examining women’s vaginal discharge, discovered Trichomonas vaginalis almost 180 years ago. Moreover, studies have found that Trichomonas vaginalis can coexist with syphilis and gonorrhea in one organism.
- Two years later, the German zoologist Christian Gottfried Ehrenberg classified T. vaginalis as the ciliated protozoa. However, further research had been stopped. Ehrenberg believed that T. vaginalis (like most ciliates) is relatively harmless.
- 35 years later, the Russian obstetrician Lazarevich Ivan Pavlovich noticed that T. vaginalis is most frequently detected in women experiencing inflammation of the genital tract.
- The pathogenicity of Trichomonas was confirmed before World War II. Then scientists spent the following two decades trying to identify the transmission route of the infection.
How do People Get Trichomoniasis?
Trichomoniasis is transmitted mainly through unprotected vaginal sexual contact.
The infection spreads when the genitals come into contact with infected vaginal fluids during sex. Both men and women can pass the parasite to their sexual partners.
Transmission between female partners is possible, although it occurs less often.
Infection between male partners is considered uncommon. Trichomoniasis is also not typically spread through oral sex.
The parasite does not survive well outside the human body, so getting infected through toilet seats, shared towels, or swimming pools is considered extremely unlikely.
Trichomoniasis Symptoms
Most infected people have an asymptomatic course of trichomoniasis. According to some sources, 70%–80% of patients have minimal or no genital symptoms. Signs and symptoms of infection may appear 5-28 days after exposure.
Common Symptoms of Trichomoniasis in Men and Women
- genital itching or irritation
- redness in the genital area
- burning sensation when urinating
- discomfort during intercourse and urination
- lower abdominal pain (in rare cases)
Symptoms of Trichomoniasis in Women
- frothy vaginal discharge (usually yellow or green) with an unusual, foul odor
- inflammation and redness of the vulva
- sores in the mucous membrane of the vagina
Symptoms of Trichomoniasis in Men
- mucus-like urethral discharge
- hematospermia, the presence of blood in the semen (in rare cases)
- rash on the glans (head of the penis)
What Makes Trichomoniasis Dangerous?
Trichomoniasis is often called a “mild” STI because many people have no symptoms.
But even a silent infection can affect your health in several important ways.
- It makes HIV infection more likely.
According to public health experts, people with trichomoniasis have about a 1.5-times higher risk of getting HIV. The infection also increases the amount of virus in genital fluids, which can make transmission easier.
- It can lead to pregnancy complications.
Trichomoniasis has been linked to premature birth, early rupture of the amniotic sac, and babies being born with low birth weight or smaller than expected for their gestational age.
- It may cause deeper pelvic infections in women with HIV.
In this group, trichomoniasis is associated with a higher risk of pelvic inflammatory disease, a condition that can affect fertility and long-term reproductive health.
- In men, it can cause inflammation of the urinary tract and prostate.
This may lead to burning during urination, discharge, or chronic pelvic discomfort. Some studies have explored a possible link with prostate cancer, but official guidelines state that this connection has not been clearly proven.
- It has been linked to a higher risk of cervical cancer.
Researchers have found an association between trichomoniasis and cervical cancer, although this does not mean the infection directly causes cancer.
- In rare cases, the infection can pass to a baby.
Transmission during pregnancy or childbirth is uncommon, but newborns may develop genital or breathing-related infections.
Trichomoniasis and HIV
Trichomoniasis is not just an uncomfortable sexually transmitted infection. It can also make a person more vulnerable to HIV. Studies show that people infected with Trichomonas vaginalis have a higher risk of acquiring HIV compared with those who are not infected.
This happens mainly because the parasite causes inflammation in the genital tissues. Inflamed mucous membranes become more fragile and can develop tiny microscopic breaks. During sexual contact, these small повреждения may create an easier pathway for HIV to enter the body.
The infection also triggers an immune response. The body sends protective immune cells to the affected area, but HIV specifically targets these cells. As a result, their increased presence in inflamed tissues may unintentionally raise the likelihood of HIV transmission.
For individuals who are already living with HIV, trichomoniasis can increase the amount of virus released in genital secretions. This may make it easier to pass HIV to a sexual partner even when symptoms of trichomoniasis are mild or completely absent.
Trichomoniasis is also seen more often in women with HIV and has been linked to a higher risk of pelvic inflammatory disease in this group, which can affect long-term reproductive health.
Trichomoniasis and Pregnancy
Trichomoniasis during pregnancy has been linked to a higher risk of certain complications.
Research shows that the infection may increase the likelihood of preterm birth, meaning delivery before 37 weeks of pregnancy, as well as low birth weight in newborns.
Babies who are born too early or weigh less than expected may face more health challenges. These can include breathing difficulties, problems with feeding and temperature control, and a higher risk of developmental concerns later in life.
Transmission of trichomoniasis from mother to baby is considered uncommon, but it can still occur. In rare cases, newborns exposed to the infection may develop respiratory or genital infections.
For this reason, timely diagnosis and appropriate treatment during pregnancy are important. Managing the infection helps reduce the risk of complications and supports safer outcomes for both the mother and the baby.
How is Trichomoniasis Prevented?
- Use condoms. Condoms are the best way to prevent STIs during sex. It is very important that condoms are put on before any sexual contact occurs between the penis, vagina, mouth, or anus. Contraction and transmission of trich can occur without ejaculation. Other methods of birth control, like birth control pills, shots, implants, or diaphragms, will not protect against STIs.
- Get tested. Make sure your partner is also tested for STIs before having sex.
- Practice monogamy.
- Limit your number of sexual partners. STI risk increases with the number of sexual partners.
If you are exposed to trichomoniasis, you should get tested for other STIs, since they could be transmitted at the same time as trich.
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