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Patient Story

A 17-year-old teen presents with a vaginal itching, odor, and discharge for several weeks. She has one partner who is asymptomatic. Speculum examination shows a cervix (Figure 78-1) with a copious foamy white discharge with a fishy odor. Wet mount shows trichomonads swimming in saline (Figures 78-2 and 78-3). The trichomonads are larger than white blood cells (WBCs) and have visible flagella and movement. She is diagnosed with trichomoniasis and treated with 2 g of metronidazole in a single dose. The patient is tested for other sexually transmitted diseases (STDs) and her partner is treated with the same regimen.


Trichomonas infection seen on the cervix. There is a thick foamy off-white discharge. (Used with permission from Richard P. Usatine, MD.)


Wet mount showing Trichomonas in saline under low power. There are two visible trichomonads to the right and above the tip of the pointer. The largest cells are vaginal epithelial cells with visible nuclei. (Used with permission from Richard P. Usatine, MD.)


Wet mount showing Trichomonas (arrows) in saline under high power. The smaller more granular cells are white blood cells. (Used with permission from Richard P. Usatine, MD.)


Trichomonas vaginitis is a local infection caused by the protozoan Trichomonas vaginalis that is associated with vaginal discharge and irritation. The patient often has an itch and an odor along with the discharge but may be asymptomatic.


Trichomoniasis, trich, tricky monkeys.


  • An estimated 3 to 5 million cases of trichomoniasis occur each year in the US.1

  • The worldwide prevalence of trichomoniasis is estimated to be 180 million cases per year; and these cases account for 10 to 25 percent of all vaginal infections.2

  • Cross-sectional data from the 2003 to 2004 US National Health and Nutrition Examination Survey (NHANES) shows 3 percent of female adolescents (aged 14 to 19 years) had laboratory evidence of infection with Trichomonas vaginalis.3

Etiology and Pathophysiology

  • Trichomonas infection is caused by the unicellular protozoan T. vaginalis.4

  • The majority of men (90%) infected with T. vaginalis are asymptomatic, but many women (50%) report symptoms.5

  • The infection is predominantly transmitted via sexual contact. The organism can survive up to 48 hours at 10°C (50°F) outside the body, making transmission from shared undergarments or from infected hot spas possible although extremely unlikely.

  • Trichomonas infection is associated with low-birth-weight infants, premature rupture of membranes, and preterm delivery in pregnant patients.6

  • In a ...

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