Chapter 210 Trichomoniasis
Diagnostic Summary
• Profuse malodorous white to green discharge from the vagina.
• Discharge usually has a pH greater than 4.5, a weak amine odor, and large numbers of white blood cells and trichomonads on wet mount.
• Vulvovaginal pruritus, burning, and/or irritation.
• Vulva and introitus usually show erythema.
• Cervix may or may not have a mottled erythema—“strawberry cervix” (less than 5%).
• Dysuria and/or dyspareunia may be present.
• Rule out trichomoniasis in males exhibiting signs of prostatitis, urethritis, or epididymitis.
General Considerations
Trichomonas vaginalis infection is a common cause of vaginal irritation in women and is the most common nonviral sexually transmitted disease in the world. It is estimated to affect 5 million women in the United States each year alone. One in five women in the United States will have trichomoniasis at some time in her life. Aside from these alarming statistics, there are other reasons for taking trichomonal infections seriously, as follows1,2:
• Gonorrhea and trichomoniasis are common coexisting infections, with up to 40% of women with trichomoniasis having gonorrhea and vice versa.
• Trichomoniasis is a common cause (90%) of cervical erosion and therefore may be a factor in malignant transformation.
• Trichomoniasis may complicate interpretation of Papanicolaou smears, increasing the number of false-positive results.
• Trichomoniasis raises the rate of sterility among males and females, in the latter as a result of salpingitis and in the former because of toxic products that decrease the motility of spermatozoa.
• The rate of postpartum fever and discharge is higher in women in whom T. vaginalis infection occurs at delivery.
• Neonates infected via the birth canal may manifest serious illness (rare).
• Prostatitis and epididymitis are common in infected males.
• Trichomoniasis increases transmission and infectivity of human immunodeficiency virus (HIV), such that HIV-seropositive men with concomitant trichomoniasis may have a sixfold higher concentration of HIV RNA in their seminal plasma.
• Infection may confuse and/or complicate other urinary or genital tract problems.
Diagnosis
T. vaginalis is a flagellate 15 to 18 micrometers in length. It is shaped like a turnip, with three to four anterior flagella and one posterior flagellum mounted in an undulating membrane. It is transmitted via sexual intercourse. Although women in the past have been thought to be the primary reservoir for Trichomonas and men merely the vector, the medical literature now suggests that men are also reservoirs.3,4
Diagnosis is made from clinical signs and symptoms (see the diagnostic summary), saline wet mount, and culture. Trichomonal cultures (using the Feinberg Trichomonas medium) have recently been advocated to improve diagnostic sensitivity. Although the wet mount is one of the most commonly used and quickest methods to achieve a diagnosis, multiple studies have demonstrated that, compared with culture, the sensitivity of a wet mount ranges from only 45% to 60%.1,2 In men, a reliable culture site has not been established, and cultures from urine and seminal samples have consistently afforded a low yield. Among patients with trichomonal vaginitis, the organism can be cultured from the vagina and paraurethral glands in 98%, from the urethra in 82%, and from the endocervix in 13%. In only 56% to 65% of patients is T. vaginalis seen on a Papanicolaou smear, thus making the smear an unreliable form of diagnosis.1,2 However, recent data suggest that the positive predictive value of this test is acceptable for a diagnosis of trichomoniasis when it is found incidentally on Papanicolaou smear. A meta-analysis found a sensitivity of 57% and a specificity of 97%.5
Rapid point-of-care tests for trichomonal vaginitis are now available; they include the OSOM Trichomonas Rapid Test (Genzyme Diagnostics, Cambridge, Mass), an immunochromatographic capillary-flow dipstick technology, and the Affirm VP III (Becton Dickinson, Franklin Lakes, NJ), a nucleic acid probe test that evaluates for trichomonal vaginitis, Gardnerella vaginalis, and Candida albicans.1 Both of these tests are performed on vaginal secretions and have a sensitivity greater than 83% and a specificity greater than 97%. The results of the OSOM Trichomonas Rapid Test are available in about 10 minutes, and the results of the Affirm VP III are available within 45 minutes. These tests tend to greatly assist physicians in the accurate and timely diagnosis of trichomoniasis.
Trichomonal Vaginitis
Sexual transmission is the clear route of Trichomonas infection. Prevalence is highest among women with multiple sex partners and in those with other sexually transmitted infections. Transmission rates from men to women seem to be high, because an 80% to 100% prevalence rate is found in the female partners of infected men.4 In the female, T. vaginalis usually infests the vagina and urethra. However, infection may involve the endocervix, Bartholin glands, Skene glands, or bladder. The vagina appears to be a good reservoir for the organism. Under stimulation of estrogen, the vaginal walls are well glycogenated—essential for T. vaginalis to thrive. Prepubescent and postmenopausal women seldom have symptomatic trichomonal infections.
Trichomonas in the Male
Although the incidence is lower in men, 5% to 15% of cases of nongonococcal urethritis are estimated to be caused by trichomonal infections.1,2 The estimated transmission rate is 70% for men who have had sexual contact with infected women in the previous 48 hours.2 Men with T. vaginalis are most often asymptomatic, yet mild cases of urethritis, prostatitis, and epididymitis have been reported. As might be expected, trichomoniasis is a factor in male infertility.4 Trichomonads have been identified in semen, urethral discharge, urine, and prostatic fluid and have been found in the prostatic secretions and semen in up to 23% of men with chronic nongonococcal prostatitis.6
Although men were thought to be the only vectors for Trichomonas, the parasite is now known to persist in the male reproductive tract. The reinfection of treated females who are sexually active is well documented.4 Therefore, treatment of both sex partners is necessary. Furthermore, among both women and men, the association of T. vaginalis with enhanced HIV acquisition and transmission has been well documented.2
Therapeutic Considerations
Conventional Treatment
Conventional therapy of trichomoniasis involves metronidazole7 and tinidazole, a second-generation nitroimidazole used to treat metronidazole-resistant infection. Randomized controlled trials comparing tinidazole (2-g single oral dose) and either metronidazole (2-g single oral dose) or short-course metronidazole have demonstrated parasitologic cure rates of 86% to 100% for all treatments, although tinidazole is slightly more effective but also more expensive. In a Cochrane Database meta-analysis of randomized trials comparing short-course therapy with tinidazole and short-course therapy with metronidazole for trichomoniasis, metronidazole had significantly higher rates of parasitologic failure, clinical failure, and adverse effects.8 Again, in order to reduce recurrence rates, sex partners should be treated at the same time.
If metronidazole or inidazole treatment is chosen, probiotic supplementation should accompany it. In the treatment of bacterial vaginosis, administration of vaginal insertion with L. acidophilus has led to cure rates superior to those with metronidazole.9,10 This suggests some benefit in vaginal trichomoniasis, given the frequent disruption of proper vaginal flora in these women.
Diet
Dietary factors affect the body’s ability to defend itself against foreign invaders and substances both directly and indirectly. As with any infection, it is not the pathogenicity of the organism but rather the “fertility of the soil” that allows the organism to grow and flourish. A well-balanced diet high in natural fiber (vegetable, fruits) and low in fat, sugar, and refined carbohydrates aids immune function (see Chapter 56 for more discussion) and may discourage any concomitant overgrowth of Candida.
Lifestyle
Depression and anxiety have been associated with exacerbations of trichomonal infections. Therefore, efforts to reduce stress are definitely indicated. Reduction may be achieved by a variety of means, including exercise and meditation.
Nutritional Supplements
In addition to the basic supplements for immune support described in Chapter 56, zinc supplementation appears to be an important consideration in the treatment of trichomonal infections in both men and women. The antimicrobial spectrum of zinc is broad and comprises many potential genitourinary pathogens, including T. vaginalis as well as Candida albicans and Chlamydia trachomatis and many viruses.11 Trichomonads are readily killed by zinc at a concentration of 0.042% (6.4 mmol/L), a concentration that can occur in the prostatic fluid of men. The zinc concentration of prostatic fluid ranges from 0.015% to 0.10% (2.3 to 15.3 mmol/L).11 This finding suggests that persistent trichomonal infections in men may be due to a low-level zinc deficiency. Zinc sulfate (220 mg twice daily for 3 weeks) has been recommended as a possible treatment for trichomonal infections that are refractory to metronidazole.12
For women with drug-resistant trichomoniasis, zinc douches in combination with metronidazole may provide welcome relief. In a small study, the women with recalcitrant trichomoniasis (4 months to 4 years culture-positive despite conventional treatment), all became culture-negative through the use of a combination of 1% zinc sulfate douching (for 3 days after each menstrual period) and 1.6 to 2.2 g/day of metronidazole (suppositories plus oral administration).13
Topical Trichomonacides
Povidone-Iodine
Iodine has long been recognized as a highly potent trichomonacide. Povidone-iodine (PVP) has a broad therapeutic effect in killing a large number of different microorganisms that cause vaginitis, including T. vaginalis.14,15 PVP (iodine, which is absorbed into polyvinyl pyrrolidine) has several advantages over iodine in that it has little sensitizing potential, does not sting, is water-soluble, and washes out of clothing.
A success rate of 98.1% has been reported in patients with intractable trichomonal, monilial, nonspecific, and mixed vaginitis for a 2-week treatment regimen using PVP (Betadine) preparations.16,17 Other studies suggest a 28-day course of povidone-iodine pessaries, particularly if the patient is using oral contraceptives.18
Propolis
An ethanol extract of propolis (150 mg/mL) has been shown to have a 100% lethal effect in vitro on the protozoans T. vaginalis and Toxoplasma gondii after 24 hours of contact.19 This extract has also been shown to diminish the inflammation associated with trichomonal vaginitis.
Essential Oils
The diverse antimicrobial action of essential oils has been well demonstrated. Many possess strong antitrichomonal properties. In a study of 40 essential oils tested for their ability to kill Trichomonas, Mentha piperita (peppermint) and Lavandula angustifolia (lavender) had the fastest killing effects (20 and 15 minutes, respectively).20
Melaleuca alternifolia
M. alternifolia (tea tree) oil is a powerful cidal agent (see Chapter 102). Commonly used as a germicidal agent in Great Britain and Australia, a 40% solution of tea tree oil has been found to be a highly effective treatment.21 The 40% solution of the oil produced no irritation, burning, or other side effects. Daily vaginal douches with a 0.4% solution of Melaleuca oil in 1 L of water was also found to be effective.22
Berberine-Containing Botanicals
The plant alkaloid berberine sulfate has been shown in vitro to inhibit the growth of several protozoa, including Entamoeba histolytica, Giardia lamblia, and T. vaginalis.23,24 No clinical trials of this agent have been reported in trichomonas vaginalis (see Chapter 97 for further discussion).
Therapeutic Approach
Given the risk of serious sequelae of trichomoniasis and the high success rate of conventional pharmaceutical intervention, systemic metronidazole should be carefully considered as a possible first-line treatment along with simultaneous and subsequent naturopathic therapies to decrease the risk of future recurrence and to treat some of the contributing underlying susceptibilities. Naturopathic therapies may be used as first-line therapy in patients who are allergic to metronidazole or are pregnant. The use of metronidazole in pregnancy remains somewhat of a controversy despite its apparent lack of teratogenic action, because data have accumulated that despite the role of T. vaginalis in perinatal morbidity, metronidazole treatment may actually increase the risk of preterm birth.25,26 Discussion with the patient of such factors as diet, sexual habits, and lifestyle is a must. The clinician should inform the patient that Trichomonas infection is a sexually transmitted disease and that treatment of the sex partners is necessary to prevent reinfection. During the treatment, sexual intercourse should be avoided. If intercourse does occur, a condom must be used.
Topical Treatments
• Betadine douche, pessary, or saturated tampon: twice a day for 14 days
• M. alternifolia oil (40% solution): swabbed on affected area two times/day or used as a douche, 1 L of a 0.4% solution twice a day or a suppository, one at night
• Zinc sulfate douche: 1% solution twice a day
• Lactobacillus insertions or douches a day, preferably in the morning
1. Wendel K.A., Workowski K.A. Trichomoniasis: challenges to appropriate management. Clin Infect Dis. 2007 Apr 1;44(suppl 3):S123–S129.
2. Soper D. Trichomoniasis: under control or undercontrolled? Am J Obstet Gynecol. 2004;190:281–290.
3. Langley J.G., Goldsmid J.M., Davies N. Venereal trichomoniasis: role of men. Genitourin Med. 1987;63:264–267.
4. Saperstein A.K., Firnhaber G.C. Clinical inquiries: should you test or treat partners of patients with gonorrhea, chlamydia, or trichomoniasis? J Fam Pract. 2010 Jan;59(1):46–468.
5. Wiese W., Patel S.R., Patel S.C., et al. A meta-analysis of the Papanicolaou smear and wet mount for the diagnosis of vaginal trichomoniasis. Am J Med. 2000;108:301–308.
6. Gardner W.A., Jr., Culberson D.E., Bennet B.D. Trichomonas vaginalis in the prostate gland. Arch Pathol Lab Med. 1986;110:430–432.
7. Workowski K.A., Levine W.C. Sexually transmitted diseases treatment guidelines 2002. MMWR Morbid Mortal Wkly Rep. 2002;51(RR06):1–78.
8. Forna F., Gulmezoglu A.M. Interventions for treating trichomoniasis in women. Cochrane Database Syst Rev. 2003;2:218.
9. Anukam K.C., Osazuwa E., Osemene G.I., et al. Clinical study comparing probiotic Lactobacillus GR-1 and RC-14 with metronidazole vaginal gel to treat symptomatic bacterial vaginosis. Microbes Infect. 2006 Oct;8(12-13):2772–2776.
10. Marcone V., Calzolari E., Bertini M. Effectiveness of vaginal administration of Lactobacillus rhamnosus following conventional metronidazole therapy: how to lower the rate of bacterial vaginosis recurrences. New Microbiol. 2008 Jul;31(3):429–433.
11. Krieger J.N., Rein M.F. Zinc sensitivity of Trichomonas vaginalis: in vitro studies and clinical implications. J Inf Disease. 1982;146:341–345.
12. Willmott F., Say J., Downey D., et al. Zinc and recalcitrant trichomoniasis. Lancet. 1983;1:1053.
13. Houang E.T., Ahmet Z., Lawrence A.G. Successful treatment of four patients with recalcitrant vaginal trichomoniasis with combination of zinc sulfate douche with metronidazole therapy. Sex Transm Dis. 1997;24:116–119.
14. Gershenfeld L. Povidone-iodine (PVP-I) as a trichomonacide. Am J Pharm Sci Support Public Health. 1962;134:324–331.
15. Gershenfeld L. Povidone-iodine as a topical antiseptic. Am J Surg. 1957;94:938–939.
16. Shook D.M. Clinical study of povidone-iodine regimen for resistant vaginitis. Curr Ther Res Clin Exp. 1963;5:256–263.
17. Mayhew S.R. Vaginitis: a study of the efficacy of povidone-iodine in unselected cases. J Int Med Res. 1981;9:157–159.
18. Henderson J.N., Tait I.B. The use of povidone-iodine (“Betadine”) pessaries in treatment of candidal and trichomonal vaginitis. Curr Med Res Opinion. 1975;3:157–162.
19. Starzyk J., Scheller S., Szaflarski J., et al. Biological properties and clinical application of Propolis. II. Studies on the antiprotozoan activity of ethanol extract of propolis. Arzneimittelforschung. 1977;27:1198–1199.
20. Jankov N., Baltova E., Topalov V., et al. Action of some essential oils on Trichomonas vaginalis. Folia Med (Plodiv). 1968;10:308.
21. Humphrey E.M. New Australian germicide. Med J Aus. 1930;1:417.
22. Pena E.F. Melaleuca alternifolia oil: its use for trichomonal vaginalis and other vaginal infections. Obstet Gynecol. 1962;19:793–795.
23. Kaneda Y., Torii M., Tanaka T., et al. In vitro effects of berberine sulphate on the growth and structure of Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis. Ann Trop Med Parasitol. 1991;85:417–425.
24. Kaneda Y., Tanaka T., Saw T. Effects of berberine, a plant alkaloid, on the growth of anaerobic protozoa in axenic culture. Tokai J Exp Clin Med. 1990;15:417–423.
25. Klebanoff M.A., Carey J.C., Hauth J.C., et al. Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection. N Engl J Med. 2001;345:487–493.
26. Kigozi G.G., Brahmbhatt H., Wabwire-Mangen F., et al. Treatment of Trichomonas in pregnancy and adverse outcomes of pregnancy: a subanalysis of a randomized trial in Rakai, Uganda. Am J Obstet Gynecol. 2003;189:1398–1400.
