Trichomonas infection is a very common sexually transmitted disease. This infection is caused by a microscopic parasite called Trichomonas vaginalis. It mostly affects sexually active women with multiple partners.   The parasite passes during sexual contact from the genitals of one person to the other.

Common Symptoms:  Most who are infected do not have symptoms.  Only about 30% of infected people develop symptoms that usually appear between 5-28 days after infection.  Symptoms are from a mild irritation, itchy or burning sensation during urination to a severe inflammation.  If untreated, the infection can last from a couple of months to years.   It is important to note that untreated vaginal inflammation can make a woman more physically prone to infection by other STD like HIV. 

Lack of specific symptoms, cause for diagnosis to be dependent on laboratory tests.  The most commonly used to detect Trichomonas infection are:

Wet Prep - The most common way to test for this infection in the laboratory is through direct microscopic examination for the parasite.  The genital is swabbed with a sterile swab and inserted in a saline solution.  This solution can either be tested under the microscope at the doctor's office or sent to the laboratory for testing.  The picture in this article is of a wet mount examination showing two parasites.

Cytology – Trichomonas parasite can also be detected during the routine PAP smear examination in the laboratory.

Culture- For the parasite is performed in the microbiology laboratory with a time to result of about 7 days. However, this is the least common of the tests for Trichomonas.

Direct Fluorescent Antibody (DFA) can also be performed to test for the parasite.

Polymerase Chair Reaction (PCR) are the most sensitive as are other Molecular tests to detect parasite DNA which are also available.

The Center for Disease Prevention and Control (CDC) has published a easy to read fact sheets on all the Sexually Transmitted Diseases and related conditions.


Two trichomonas vaginalis magnified

Two trophozoites of T. vaginalis obtained from in vitro culture, stained with GiemsaCredit: CDCCredit: CDC