Trichomoniasis

Definition

Trichomoniasis refers to an infection of the genital and urinary tract. It is the most common sexually transmitted disease, affecting about 120 million women worldwide each year.

Description

Trichomoniasis is caused by a protozoan (the smallest, single-celled members of the animal kingdom). Trichomonas vaginalis is passed almost 100% of the time through sexual contact. Trichomoniasis is primarily an infection of women's vaginal and urinary tracts. A woman is most susceptible to infection just after having completed her menstrual period. Men may carry the organism unknowingly, since infection in men may cause mild or no symptoms.

Causes and symptoms

Because trichomoniasis is a sexually transmitted disease, it occurs more often in individuals who have multiple sexual partners. The protozoan is passed to an individual by contact within the body fluids of an infected sexual partner. It often occurs simultaneously with other sexually transmitted diseases, especially gonorrhea.

In women, the symptoms of trichomoniasis include an unpleasant vaginal odor, and a heavy, frothy, yellow discharge from the vagina. The genital area (vulva) is often very itchy, and there is frequently pain with urination or with sexual intercourse. The labia (lips) of the vagina, the vagina itself, and the cervix (the narrowed, lowest segment of the uterus which extends into the upper part of the vagina) will be bright red and irritated.

In men, there are usually no symptoms at all. Occasionally, a man will notice a small amount of yellowish discharge from his penis, usually first thing in the morning. There may be some inflammation of the urethra, or urethritis, which produces mild discomfort while urinating.

The use of antibiotics is a contributing factor to recurrent trichomoniasis in some women because antibiotics affect the balance of bacteria in the vagina, allowing such organisms as T. vaginalis to multiply more rapidly.

Diagnosis

Diagnosis is easily made by taking a sample of the discharge from the women's vagina, or from the opening of the man's penis. The sample is put on a slide, and viewed under a microscope. The protozoa, which are able to move about, are easily viewed.

Trichomoniasis tends to be underdiagnosed in men because of the relative mildness of symptoms in men and insufficiently sensitive diagnostic tests. The recent introduction of DNA amplification, however, indicates that the incidence of trichomoniasis in men is much higher than was previously thought.

Treatment

The usual treatment is a single large dose of metronidazole, or split doses over the course of a week. Sexual partners of an infected individual must all be treated, to prevent the infection being passed back and forth.

Women who are taking antibiotics for other illnesses should speak to their health care provider about the possibile effects of the medication(s) on the balance of organisms in their vagina.

As of late 2003, the number of cases of metronidazole-resistant trichomoniasis appears to be increasing rapidly. Some success has been reported with the broad-spectrum anti-parasitic drug nitazoxanide, but further research needs to be done. A group of researchers in Thailand is currently investigating the effectiveness of a group of drugs known as bisquaternary quinolinium salt compounds in treating trichomoniasis.

Alternative treatment

Cure of trichomoniasis may be difficult to achieve with alternative treatments. Some practitioners suggest eliminating sweets and carbohydrates from the diet and supplementing with antioxidants, including vitamins A, C, and E, and zinc. Naturopaths may recommend treatment with two douches (a wash used inside the vagina), alternating one in the morning and one at bedtime. One douche contains the herbs calendula (Calendula officinalis), goldenseal (Hydrastis canadensis), and echinacea (Echinacea spp.); the other douche contains plain yogurt. The herbal douche helps to kill the protozoa, while the yogurt reestablishes healthy flora in the vagina. Another herbal remedy that is sometimes used is tea tree oil. Acidifying the vagina by douching with boric acid or vinegar may also be useful.

Prognosis

Prognosis is excellent with appropriate treatment of the patient and all sexual partners. Without treatment, the infection can smolder on for a very long time, and can be passed to all sexual partners.

Prevention

All sexually transmitted diseases can be prevented by using adequate protection during sexual intercourse. Effective forms of protection include male and female condoms.

Key Terms

Metronidazole

An anti-infective agent regarded as the best available drug for treating trichomoniasis. It is sold under the trade names Flagyl and MetroGel.

Protozoan

A one-celled organism belonging to the simplest phylum of the animal kingdom. Trichomoniasis is caused by a protozoan.

Urethritis

Inflammation of the urethra, which is the canal that carries urine from the bladder to the outside of the body.

For Your Information

Resources

Books

• Nash, Theodore E., and Peter F. Weller. "Protozoal Intestinal Infections and Trichomoniasis." Harrison's Principles of Internal Medicine, 14th ed. Edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.
• Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Vaginitis." New York: Simon & Schuster, 2002.
• Plorde, James J. "Introduction to Pathogenic Parasites: Pathogenesis and Chemotherapy of Parasitic Diseases." Sherris Medical Microbiology: An Introduction to Infectious Diseases. Edited by Kenneth J. Ryan. Norwalk, CT: Appleton and Lange, 1994.
• Rosenthal, M. Sara. The Gynecological Sourcebook. Los Angeles, Lowell House. 1994.

• Chavalitshewinkoon-Petmitr, P., M. Ramdja,S. Kajorndechakiat, et al. "In vitro Susceptibility of Trichomonas vaginalis to AT-Specific Minor Groove Binding Drugs" Journal of Antimicrobial Chemotherapy 52 (August 2003): 287-289.
• Ching, Susanne, and Phuong H. Nguyen. "Vaginitis." eMedicine, 5 April 2002. http://emedicine.com/med/topic2358.htm.
• Davis, Annabel. "Trichomonas vaginalis: Signs, Tests, and Treatment." Nursing Times 94 (November 25-December 1, 1998): 58-59.
• Dunne, R. L., L. A. Dunn, P. Upcroft, et al. "Drug Resistance in the Sexually Transmitted Protozoan Trichomonas vaginalis." Cell Research 13 (August 2003): 239-249.
• Pirotta, M. V., J. M. Gunn, and P. Chondros. "'Not Thrush Again!' Women's Experience of Post-Antibiotic Vulvovaginitis." Medical Journal of Australia 179 (July 7, 2003): 47-49.
• Schwebke, J. R., and E. W. Hook, 3rd. "High Rates of Trichomonas vaginalis Among Men Attending a Sexually Transmitted Diseases Clinic: Implications for Screening and Urethritis Management." Journal of Infectious Diseases 188 (August 1, 2003): 465-468.

• Centers for Disease Control and Prevention (CDC). "Fact Sheet:Trichomonas Infection. http://www.cdc.gov/ncidod/dpd/parasites/trichomonas/factsht_trichomonas.htm.

Source: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Authors are Rosalyn Carson-DeWitt, MD, Rebecca J. Frey, PhD.

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