Trichomoniasis is caused by the protozoan Trichomonas vaginalis. It is the most common non-viral sexually transmitted disease (STD) worldwide. Women are affected more often than men. Trichomoniasis is one of the three major causes of vaginal complaints among reproductive aged women, along with bacterial vaginosis and candida vulvovaginitis , and a cause of urethritis in men; however, the infection is often asymptomatic.
MICROBIOLOGY AND TRANSMISSION
The organism responsible for trichomoniasis is the flagellated protozoan Trichomonas vaginalis, which principally infects the squamous epithelium in the urogenital tract: vagina, urethra, and paraurethral glands. Other less common sites include the cervix, bladder, Bartholin glands, and prostate. Humans are the only natural host.
Trichomoniasis is virtually always sexually transmitted. Although survival on fomites has been reported, fomites have no proven role in transmission. Women can acquire the disease from other women, but men do not usually transmit the infection to other men.
The incubation period is unknown; however, in vitro studies suggest an incubation period of 4 to 28 days in about 50 percent of patients .
Coexistence of T. vaginalis and bacterial vaginosis pathogens is common, with coinfection rates of 60 to 80 percent .