Risk assessment and laboratory diagnosis of trichomoniasis in men.

Control of Trichomonas vaginalis is assuming higher priority because recent studies have suggested that trichomoniasis enhances susceptibility to human immunodeficiency virus infection and the risk for delivery of low-birth weight infants. In a cross-sectional study, 50 cases were identified among 447 men attending a sexually transmitted disease clinic. As previously reported, trichomoniasis was associated with nonchlamydial nongonococcal urethritis. Other risk factors included sexual contact with an infected woman or prior treatment for trichomoniasis or nongonococcal urethritis. Urethral and first-void urine cultures were positive in 80% and 68% of positive cases, respectively. When combined, these two cultures diagnosed 49 (98%) of 50 cases. These data suggest that criteria for selection of men for culture should include presence of nonchlamydial nongonococcal urethritis, recent exposure to trichomoniasis, or a history of trichomoniasis or nongonococcal urethritis. In addition, combining urethral and urine sediment cultures may prove accurate for evaluating T. vaginalis infection.