Immune and Lymphatic
Trichomonas vaginalis, an anaerobic, parasitic flagellated protozoan, is the causative agent of trichomoniasis and is the most common pathogenic protozoan infection of humans. Trichomoniasis is a common sexually transmitted disease. Trichomoniasis, like many other sexually transmitted diseases, often occurs without any symptoms. When women have symptoms, they usually appear within 5 to 28 days of exposure. The symptoms in women include a heavy, yellow-green or gray vaginal discharge, discomfort during intercourse, unpleasant vaginal odor, and painful urination. Irritation and itching of the female genital area, and on rare occasions, lower abdominal pain can also be present. In about two-thirds of infected females, there is edema, inflammation, cell hypertrophy, and metaplasia. The symptoms in men, if present, include a thin, whitish discharge from the penis and painful or difficult urination.