Trichomonas vaginalis is a pathogenic, single celled microorganism that infects the urogenital tract. It causes vaginal infections in women and urethritis in some men. An infection with Trichmonas vaginiais is called Trichomoniasis and is a sexually transmitted disease (STD).
Image 1: Diagram of Trichomonas vaginalis (Source: Veralovic et al 10th Edition of Clinical Microbiology, 2011)
If a woman shows symptoms of infection, such as a strong-smelling vaginal discharge, genital itching, and/or pain during urination then testing should occur. A man may display symptoms of the frequent urge to urinate and/or a discharge from the urethra.
For women, a vaginal or endocervical swab is collected.
For men, a urethral swab is required.
Alternatively, both males and females can provide a first pass urine sample in a sterile container.
As symptoms warrant or if a sexual partners test positive.
The test is looking for the presence of Trichomonas vaginalis.
In women, a swab of the secretions inside the vagina is collected.
In men, a thin swab is inserted into the urethra of the penis.
Alternatively, the first portion of urine is collected for testing.
Your doctor may request the test if you show signs of symptoms, such as vaginal discharge or pain on urination. Co-infection with other sexually transmitted diseases is likely. If you have an infection with another sexually transmitted disease, your doctor might test for Trichomonas vaginalis as well. Likewise, if you are positive for Trichomonasis your doctor may test you for other STDs such as Chlamydia and Gonorrhoea. Testing may also be performed if your partner has tested positive for a STD. Re-testing may also occur to ensure that the infection has been eradicated as reinfection from an untreated partner is common.
A positive result means an infection of Trichomonasis. This requires treatment with a course of antibiotics, usually Metronidazole. All sexual partners of a positive infected person should also be tested. Infection, especially in men, can often be asymptomatic (no obvious symptoms).
A negative test means either there is no infection with T. vaginalis and symptoms are due to another cause or Trichomonas was not able to be detected in the sample using the test method performed. If Trichomoniasis is still suspected, a different testing method may be used or a repeat sample may be taken to confirm the result.
Trichomonasis is one of the most prevalent, treatable non-viral STDs, mostly affecting women. It is more common in Aboriginal populations especially in rural and remote communities.
An infected person is at greater risk of getting other STDs, so the doctor may want to test for these other infections also.
Trichomonas infection can affect pregnancy, contributing to premature birth and low birth weight. You should inform your doctor if you think you might be pregnant. The doctor may medically manage a woman who is infected and in her first three months of pregnancy differently.
In women, vaginal discharge is typically described as copious, liquid, greenish, frothy and foul smelling. Symptoms, such as intense vaginal discharge, are often sudden and frequently noted to occur during or after menstruation. Itching or redness in and around the vagina may also be experienced. Other symptoms can include pain during sexual intercourse, discomfort or swelling in the lower abdomen or groin, and the frequent urge to urinate, often with pain and burning. However, at least 10% of women with Trichomonas vaginalis infections are asymptomatic.
Most infected men have no symptoms but when they do, symptoms include discharge from the urethra, a frequent urge to urinate, and a burning sensation on urination.
It is usually treated with an antibiotic called Metronidazole. All current sexual partners should be notified and treated at the same time or the patient is likely to become re-infected.
Cervical screening test, Chlamydia trachomatis, Neisseria gonorrhoeae
Conditions: Sexually transmitted diseases
RCPA Manual: Genital swab
Better Health Channel: Trichomoniasis
Queensland Government: Sexual Health
Register of Public Sexual Health Clinics in Australia and New Zealand (pdf)
Last Review Date: March 22, 2021