Trichomoniasis is caused by Trichomonas vaginalis, a single cell protozoan parasite with a whip-like tail that it uses to propel itself through vaginal and urethral mucus. This sexually-transmitted disease (STD) is found worldwide.

In the United States the highest incidence is in women between 16 and 35 years of age. This disease-causing protozoan cannot survive in the mouth or rectum, and therefore must be transmitted through penis-to-vagina intercourse or vulva-to-vulva contact with an infected partner.

The symptoms of the disease are quite different in men than in women.

In men, the infection is often without symptoms (asymptomatic), and clears spontaneously in a few weeks. Symptomatic men may experience a mild urethral itching or discharge, mild burning after urination or ejaculation, and, on occasion, may develop prostatitis or epididymitis from the infection.

Women develop a frothy, foul smelling, green-white or yellowish vaginal discharge. The volume of discharge may be large. Itching may occur on the labia and inner thighs and the labia may appear swollen.

Data on the incidence and prevalence of trichomoniasis is not as complete as that for gonorrhea and syphilis. Figures suggest that it is a frequently encountered infection. More than half of all females with gonorrhea also have trichomonas. Frequently, individuals with one diagnosed STD have one or more additional sexually-transmitted infections.

• discomfort with intercourse
• vaginal itching
• profuse, greenish-yellow, frothy or foamy, vaginal discharge with a foul or strong smell (malodorous)
• labial swelling or vulvar itching
• itching of the inner thighs

• burning after urination or ejaculation
• itching of urethra
• slight discharge from urethra

• A wet prep (microscopic examination of discharge) demonstrates rapidly moving (motile) trichomonads in the vaginal secretions.
• A pap smear may also detect the presence of the organism.

In men, the disease can be hard to diagnose without special culture techniques, but men are treated presumptively if infection is diagnosed in female sexual partners.

Men may also be treated presumptively if they have ongoing symptoms of urethral burning and/or itching despite treatment for gonorrhea and chlamydia.

If prolonged infection is present, it may cause changes in the tissue on the cervical surface. These changes may be noted on a routine Pap smear. In such cases, treatment should be initiated and the Pap smear repeated 3 to 6 months after successful treatment.

It is important that trichomoniasis be treated to prevent symptoms and transmission to partners. Trichomoniasis can also increase the probability of acquiring HIV infection from an infected partner.

Trichomoniasis is present in the sexually active population of all ages. A monogamous sexual relationship with a known healthy partner can help reduce the risk of this and all other sexually-transmitted diseases.

Barring total abstinence, condoms remain the best and most reliable protection against this and other sexually-transmitted diseases. Condoms must be used consistently and correctly. See safer sex behaviors.