TRICHOMONIASIS is an important sexually transmitted disease (STD) that is associated with increased perinatal morbidity and increased HIV transmission. Infection with Trichomonas vaginalis also results in local urogenital tract symptoms. Standard teaching is that trichomoniasis is an important cause of vaginitis in women, but that male sexual partners experience little or no morbidity. The widespread belief that men are asymptomatic carriers of infection persists among most clinicians despite a slowly growing literature suggesting the contrary.
Given the high incidence and prevalence of trichomoniasis, there is sparse literature on infection in men. In MEDLINE searches, only 79 articles published during the last 25 years considered trichomoniasis in the male urogenital tract, 40 of which were published in English. Of these 40 articles, 11 (28%) appeared exclusively in Sexually Transmitted Diseases.
It is worthwhile to summarize critical findings in this remarkable series of articles from Sexually Transmitted Diseases. Most studies used varied diagnostic approaches to describe the prevalence of trichomoniasis in different populations. Zigas1 found an 11% prevalence among Melanesian men in New Guinea, compared with a 0% rate among white men. Short2 found that trichomoniasis was three times more common among blacks than among whites. Saxena diagnosed trichomoniasis in 58% of 16- to 22-year-old men in a job training program, and found that pyuria was more common among T vaginalis-positive patients (P = 0.01). Harms3 diagnosed trichomoniasis in 9% of 125 Malagasy men with urethral discharge. Conversely, Jainer et al4 found T vaginalis in only 1% of 219 Parisian men with urethral symptoms.
Other workers concentrated on the clinical presentation of trichomoniasis in men. Latif5 found that urethral discharge and irritation were the most common symptoms in 325 African men with urethral trichomoniasis. Of these 325 patients, 252 (78%) had had symptoms for more than 4 weeks. Kuberski6,7 found that the typical clinical presentation was persistent urethritis and/or prostatitis due to an antibiotic-resistant agent. I8 reviewed our own studies documenting T vaginalis in 11% of 447 men at risk for STDs. Although 54% of infected men reported urethral discharge, this discharge was only mild or moderately severe. Elimination of T vaginalis was associated with resolution of urethritis. A recent study by Hobbs et al9 detected trichomoniasis in 51 (17%) of 293 Malawian men. The prevalence was 21% among symptomatic men compared with 12% among asymptomatic men. HIV-seropositive men with T vaginalis infection had significantly higher HIV RNA concentrations in their seminal plasma than HIV-positive men without trichomoniasis. T vaginalis may infect other urogenital sites, such as the prostate.10,11 Negative urine and urethral cultures have been documented in some men with such invasive infections.12
Joyner et al13 expand and elaborate on these earlier themes, and argue that trichomoniasis is an important cause of urogenital symptoms in sexually active men. Among men attending their STD clinic, trichomoniasis was associated with nongonococcal urethritis. This was especially true in men older than 30 years; trichomoniasis was diagnosed in 5.1% of 214 patients, representing a higher rate than either gonorrhea (2.8%) or chlamydial infection (3.3%). The duration of symptoms of urethritis was longer among men with trichomoniasis (median, 14 days) than among men with either chlamydial infection (median, 7 days) or gonorrhea (median, 3 days). Despite different diagnostic methods and different patient populations, these data agree with those of other recent studies documenting a high prevalence of trichomoniasis among men attending STD clinics.
Taken together, this slowly growing body of data suggests that T vaginalis represents an important consideration in the differential diagnosis of urethritis. Trichomoniasis is “no longer a minor STD.”16 Currently, the Centers for Disease Control and Prevention recommend testing or empirical therapy for patients who do not respond to antichlamydial treatment. Indications should be expanded to include older men, those with mild urethritis, or those with longstanding symptoms. T vaginalis is an important cause of urethritis in sexually active men, especially older men with urethral symptoms or inflammation but little or no evidence of discharge on physical examination.
1. Zigas, V. An evaluation of trichomoniasis in two ethnic groups in Papua New Guinea. Sex Transm Dis 1977; 4:63–65.
2. Short SL, Stockman DL, Wolinsky SM, Trupei MA, Moore J, Reichman RC. Comparative rates of sexually transmitted diseases among heterosexual men, homosexual men, and heterosexual women. Sex Transm Dis 1984; 11:271–274
3. Harms G, Matull R, Randrianasolo D, et al. Pattern of sexually transmitted diseases in a Malagasy population. Sex Transm Dis 1994; 21:315–320.
4. Janier M, Lassau F, Casin I, et al. Male urethritis with and without discharge: a clinical and microbiological study. Sex Transm Dis 1995;22:244–252.
5. Latif AS, Mason PR, Marowa E. Urethral trichomoniasis in men. Sex Transm Dis 1987; 14:9–11.
6. Kuberski T. Trichomonas vaginalis
associated with nongonococcal urethritis and prostatitis. Sex Transm Dis 1980; 7:135–136.
7. Kuberski T. Evaluation of the indirect hemagglutination technique for study of Trichomonas vaginalis infections, particularly in men. Sex Transm Dis 1978; 5:97–102.
8. Krieger JN. Trichomoniasis in men: old issues and new data. Sex Transm Dis 1995; 22:83–96.
9. Hobbs MM, Kazembe P, Reed AW, et al. Trichomonas vaginalis
as a cause of urethritis in Malawian men. Sex Transm Dis 1999; 26:381–387.
10. Gardner WA Jr, Culberson DE, Bennett BD. Trichomonas vaginalis
in the prostate gland. Arch Pathol Lab Med 1986; 110:430–432.
11. Krieger JN, Riley DE, Roberts MC, Berger RE. Prokaryotic DNA sequences in patients with chronic idiopathic prostatitis. J Clin Microbiol 1996; 34:3120–3128.
12. Krieger JN, Verdon M, Siegel N, Holmes KK. Natural history of urogenital trichomoniasis in men. J Urol 1993; 149:1455–1458.
13. Joyner JL, Douglas JM, Ragsdale S, Foster MA, Judson FN. Comparative prevalence of infection with Trichomonas vaginalis
among met attending a sexually transmitted disease clinic. Sex Transm Dis 2000 27:000–000.
14. Krieger JN, Jenny C, Verdon M, Siegel N, Springwater R, Critchlow CW, Holmes KK. Clinical manifestations of trichomoniasis in men. Ann Intern Med 1993; 118:844–8449.
15. Borchardt KA, al-Haraci S, Maida N. Prevalence of Trichomonas vaginalis
in a male sexually transmitted disease clinic population by interview, wet mount microscopy, and the InPouch TV test. Genitourin Med 1995; 71:405–406.
16. Hook EW. Trichomonas vaginalis:
no longer a minor STD. Sex Transm Dis 1999; 26:388–389.
That Trichomonas vaginalis can be a cause of urethritis is beyond dispute. What is needed now are collaborative studies that focus on geographic differences in the reported prevalence of T vaginalis among men with urethritis and on the organism's biological properties. Such studies need to better define populations that have high relative prevalence rates of T vaginalis. Stratification among patients on the basis of previous history, age, race, etc. all appear to be important. It is no longer acceptable to say, “among men with urethritis”-we have to know: Are these infected men different from other men with urethritis? The possibility that some of the organisms may be different in different parts of the world deserves study.