Trichomoniasis is correctly diagnosed less frequently in men than in women. This is largely due to the fact that the symptoms of trichomoniasis in men are not as noticable or bothersome as they are in women; if they have no reason to suspect that they are infected, they don't get tested. Another contributing factor is that the most commonly used diagnostic methods often fail to detect T. vaginalis infection in men.
Asymptomatic Infections
Most men who have trichomoniasis do not know that they have it because they either have no symptoms or their symptoms are too minor to elicit concern. In a recent study, 75% of 205 infected men claimed to be asymptomatic.1 In another study, 47% of men with trichomoniasis reported discharge and 22% had dysuria (painful urination).2 Fifty-four percent of men in a third study complained of discharge, but characterized it only as mild or moderate.3
Trichomoniasis Testing Methods
The prevalence of T. vaginalis detected in men varies according to the setting and diagnostic methods used. Diagnostic methods used with men include culture techniques, wet mount, and various staining methods (Gram's, Giemsa, Papanicolaou's, periodic acid-Schiff, and acridine orange). Wet mount examination is only 50-70% accurate in women, and it is even less reliable in men. Urethral cultures will grow T. vaginalis in only 60% of cases. Staining methods are also less accurate than direct examination and require confirmation by a second method.3
| Test | Specimen | Percent Infected |
|---|---|---|
| Culture | Urethral swab | 12.5% |
| Urine | 8.0% | |
| Semen | 10.5% | |
| Any | 16.4% | |
| PCR | Urine | 69.3% |
| Semen | 53.8% | |
| Any | 71.8% | |
| Any | Any | 73.2% |
| Table 1 | ||
Saxena (1991) found a 58% prevalence of trichomoniasis among a group of 85 "high risk" young men (ages 16-22) recruited from a job training program. The study used multiple diagnostic methods to detect infection with greater accuracy than any individual method could provide. The direct fluorescent antibody test (DFA), using a combination of urethral culture and urine sediment culture as the "gold standard," resulted in 60% sensitivity and 73% specificity. The Pap smear showed a 3% sensitivity with 96% specificity, and wet mount was 33.3% sensitive and 84.6% specific.4
Polymerase chain reaction (PCR) has recently emerged as a highly accurate diagnostic method, but is presently used only in research settings. A study by Schwebke (2002) comparing PCR to combined urine and urethral cultures found 17% prevalence (52/300) when using PCR for diagnosis vs. only 5% with combined cultures.5 Using urine PCR, Wendel (2003) found a T. vaginalis prevalence of 13% in 355 men.2
In perhaps the most definitive study to date, Hobbs (2006) compared culture to PCR in the detection of trichomonads in multiple specimens collected from 280 male sexual partners of women who had trichomoniasis. Over 73% (205/280) of the men were positive for trichomoniasis on at least one test. As shown in Table 1, culture alone only detected infection in 16.4% of the men, while PCR detected 71.8%.1
| Patient Population (n) | Trichomoniasis | Chlamydia | Gonorrhea |  |
|---|---|---|---|---|
| STD clinic, Baltimore, MD (355)2 | 13% | 11% | 19% |  |
| STD clinic, Birmingham, AL (300)6 | 17% | 19.6% | 17.7% |  |
| STD clinic, Richmond, CA (204)7 | 12% | 5% | 25% |  |
| Job training program (85)6 | 58% | 29% | 23.5% |  |
| Table 2 | ||||
- Hobbs MM, Lapple DM, Lawing LF, Schwebke JR, Cohen MS, Swygard H, Atashili J, Leone PA, Miller WC, Seña AC. Methods for detection of Trichomonas vaginalis in the male partners of infected women: implications for control of trichomoniasis. J Clin Microbiol. 2006 Nov;44(11):3994-9. Epub 2006 Sep 13.
- Wendel KA, Erbelding EJ, Gaydos CA, Rompalo AM. Use of urine polymerase chain reaction to define the prevalence and clinical presentation of Trichomonas vaginalis in men attending an STD clinic. Sex Transm Infect. 2003 Apr;79(2):151-3.
- Krieger JN, Jenny C, Verdon M, Siegel N, Springwater R, Critchlow CW, Holmes KK. Clinical manifestations of trichomoniasis in men. Ann Intern Med. 1993 Jun 1;118(11):844-9.
- Saxena SB, Jenkins RR. Prevalence of Trichomonas vaginalis in men at high risk for sexually transmitted diseases. Sex Transm Dis. 1991 Jul-Sep;18(3):138-42.
- Schwebke JR, Lawing LF. Improved detection by DNA amplification of Trichomonas vaginalis in males. J Clin Microbiol. 2002 Oct;40(10):3681-3.
- Schwebke JR, Hook EW 3rd. High rates of Trichomonas vaginalis among men attending a sexually transmitted diseases clinic: implications for screening and urethritis management. J Infect Dis. 2003 Aug 1;188(3):465-8. Epub 2003 Jul 10.
- 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 Dec;71(6):405-6.
