In the United States the highest incidence is in women between 16 and 35 years of age. Transmission is usually through sexual contact but on occasion may occur following direct contact with contaminated surfaces including wet wash cloths and toilet seats. Women can acquire the disease from infected men and women, whereas men usually only contract it from infected women. The symptoms of the disease are quite different in men than in women. Symptomatic men may experience a mild urethral itching or discharge, mild burning after urination or ejaculation, and, on occasion, may develop prostatitis or epididymitis from the infection.
Women develop a frothy, foul smelling, green-white or yellowish vaginal discharge .
The volume of discharge may be large. Itching may occur on the labia and inner thighs and the labia may appear swollen. Data on the incidence and prevalence of trichomoniasis is not as complete as that for gonorrhea and syphilis . Figures suggest that it is a frequently encountered infection. More than half of all females with gonorrhea also have trichomonas.