Trichomoniasis is a sexually transmitted disease caused by a microorganism called trichomonas vaginalis. Sexually active women are affected, while men can only be the carriers. 

Diagnosis is done by examining the vagina and taking a sample of the vaginal fluids (or urine) and testing it for the presence of the parasite (trichomonas). Its presence is much harder to determine in men rather than women. Men often don’t exhibit symptoms, and are unaware of the problem until their partner seeks medical help. If the symptoms are present these are: irritation of the penis, stinging sensation during urination or after ejaculating. In women foul smelling green- yellowish foamy  discharge appears, as well as pain during urination, rashes and vaginal oversensitivity. This causes discomfort during sex. Pain in the lower abdomen is also a symptom. Antibiotics are used as a treatment.  

Because trichomonas can survive several hours outside of the human body it is possible to get infected by the use of a toilet seat, towel or any other item used for personal hygiene. Some researchers suggest that it is usually transmitted non-sexually. If untreated it can cause infertility in men.