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- Sexually transmitted urogenital infection caused by a pear-shaped, parasitic protozoan
- Causes vaginitis/urethritis in women, nongonococcal urethritis in men
- In pregnancy, increases risk of preterm labor, preterm premature rupture of membranes, small for gestational age infant, and possibly stillbirth
- Synonym(s): trich; trichomonal urethritis
- The most common curable sexually transmitted infection (STI); in 2008, >275 million new cases worldwide, over half of curable STIs (1)
- Estimated 1.1 million new cases annually in the United States
- 10–25% of vaginal infections
- 1–17% of cases of NGU in males; reported prevalence among men without urethritis ranges from 0% to 8%.
- Predominant age: middle-aged adults
- Rare until onset of sexual activity
- Common in postmenopausal women; age is not protective and long-term carriage is common.
- Women have higher prevalence (1.5 to 4.4 times more than men) (2).
Rare in prepubertal children; diagnosis should raise concern of sexual abuse.
- 3.1% of all U.S. women age 25 to 49 years; 1.5% of U.S. women age 15 to 24 years
- Racial disparity demonstrated
- 1.3% of white, non-Hispanic women
- 1.8% of Mexican American women
- 13.3% of black, non-Hispanic women
Etiology and Pathophysiology
- Trichomonas vaginalis: a pear-shaped, flagellated, parasitic protozoan
- Grows best at 35–37°C in anaerobic conditions at pH of 5.5 to 6.0
- STI, but nonsexual transmission is possible because organism can survive several hours in moist environment.
No known genetic considerations
- Multiple sexual partners
- Unprotected intercourse
- Lower socioeconomic status
- Other STIs
- Untreated partner with previous infection
- Use of douching or feminine powders
Commonly Associated Conditions
- Other STIs, including HIV
- Bacterial vaginosis