- Sexually transmitted urogenital infection caused by a pear-shaped, parasitic protozoan
- Causes vaginitis/urethritis in women, nongonococcal urethritis in men
- Association with infertility in epidemiologic studies
- 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
- Estimated 1.1 million new cases annually in United States
- 10–25% of vaginal infections
- In males, up to 17% of nongonococcal urethritis; French study shows decreasing prevalence in men since 2007.
- 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.
- Rare in prepubertal children; diagnosis should raise concern of sexual abuse.
- Neonatal infections occur most often in the lungs, also vaginal (1)
- 2.1% in U.S. women aged 14 to 59 years
- 0.5% of U.S. men aged 14 to 59 years
- Racial disparity demonstrated
- 9.6% of black women versus 0.8% of other women
- 3.4% of black men versus 0.03% of other men
Etiology and Pathophysiology
- Trichomonas vaginalis: pear-shaped, flagellated, parasitic protozoan
- Grows best at 35–37°C in anaerobic conditions with pH 5.5 to 6.0
- Divides by binary fission, does not have a cyst form so does not survive externally
- STI, but nonsexual transmission possible because it 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
- Hormonal contraception use does NOT increase risk.
- Use of male or female condoms
- Limiting sexual partners
- Male circumcision may be protective.
Commonly Associated Conditions
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