Trichomoniasis is the most common, non-viral sexually transmitted infection in the U.S. and quite common worldwide. Many women have this infection and don’t even know! This article describes this unusual parasite and its treatment but also explains the importance of immediate treatment.


Trichomoniasis, also called Trich, is the most common, non-viral infection transmitted via intercourse in the U.S. It is also the 3rd most common cause of genital infections and like the other 2, does not cause any long term harm. As with the other causes, the symptoms tend to drive women to seek care. Additionally, this pathogen is more insidious and resilient, making complete eradication challenging.

This infection was first described in 1836 but effective treatment wasn’t discovered until over a century later. The causative organism is Trichomonas, a protozoan parasite whose only host is human. It resides in the lower genital tract of both men and women, including the urethra and is efficiently transmitted during intercourse. It is able to survive for hours in excreted urine or other bodily fluid and on soiled towels or underwear used by infected women. But transmission via these routes is possible but not likely.

Typical symptoms include a copious odorous discharge that may have a range of colors: clear, white, grey and green. The classic appearance is a frothy grayish green discharge. Other symptoms may include itching, pain with urination, frequent urination, urgent urination, pain with intercourse and even lower abdominal discomfort. It can take a few days to several weeks to develop symptoms after exposure and over 70% of people never develop any symptoms. This contributes to continued transmission and even chronic infestation lasting years, even decades.

Many women present to their doctors complaining of symptoms which may lead to detection. Some doctors perform routine checks for this infection because they recognize that it may be present without causing problems. Even though this infection does not generally cause direct harm, it is wise screen for it and treat it. It can increase the rate of transmission of other serious infections in exposed women and it has been associated with preterm labor, premature rupture of membranes and low birth weight infants in women who are infected during pregnancy.

The diagnosis can be made easily with a number of readily available tests. A wet mount is the oldest and more readily available method. It consists of taking a small sample of secretion and placing it in a drop of saline solution on a slide with a cover. Microscopic examination can easily identify the protozoa under ideal situations. An ovoid shaped organism with a flagellated structure can be seen swimming amongst epithelial and white blood cells. This protozoa with its ameboid like movements has a classic appearance on microscopic examination but can be missed if the number of organisms is low or if its motility is decreased.

Other methods for detecting trichomonas include rapid point of care tests and culture. The point of care tests utilizes methods that detect genetic material or specific structural markers of the organism. These tests have a high sensitivity and can be completed in 10-45 minutes. Cultures may take up to 1 week but combined with the wet mount can yield a nearly 100% detection rate.

Treatment consists of an oral medication which is also used to treat other bacterial and parasitic infections. Metronidazole 2 grams as a single dose or Tinidazole 2 grams also as a single dose is the standard therapy. If partners are not treated at the same time, there is a high chance of recurrence. Re-infection rates of up to 17% have been reported. There are also reports of low level resistance to the medication. In these scenarios treatment with Metronidazole 500 mg twice daily for 7 days or either of the above medications at a dose of 2 grams daily for 5 days is recommended.

Because of the theoretical risk of birth defects, treatment in pregnant women should be delayed until after the 1st trimester. If a pregnant woman has symptoms then local treatment with Clotrimazole is an alternative. It is important however to be treated as soon as possible and to get rechecked to ensure the treatment has been effective to prevent pregnancy complications.

If you have an abnormal discharge, irritation, pain or other unusual genital symptoms, it is important to be seen by a healthcare provider. Most likely the treatment will be simple however it is imperative to make sure there isn’t a more serious problem

I hope this article has provided you with information that will help you make wise choices, so you may:


Live healthy, live well and live long!