Sexually Transmitted Diseases (STDs) Slideshow Pictures

Medical Author:

Andrew K Chang, MD

Medical Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Trichomoniasis Causes

Trichomoniasis is caused by Trichomonas vaginalis, a flagellated motile protozoan.

• Approximately 174 million people worldwide are infected with this parasite each year, making it the most common curable sexually transmitted infection worldwide

• The average size of a trichomonad is 15 mm (they are not visible with the naked eye).

• Reproduction of the parasites occurs every 8-12 hours.

• Trichomonas vaginalis was isolated in 14%-60% of male partners of infected women and in 67%-100% of female partners of infected men. It is unclear why women are infected more often than men. One possibility is that prostatic fluid contains zinc and other substances that may be harmful to trichomonads.