Trichomoniasis is caused by a small parasite called Trichomonas vaginalis. The infection is acquired through sexual contact with an infected person.

Symptoms usually develop 1-4 weeks after contact, but some women do not have symptoms. 
In females symptoms include vaginal discharge which is greenish, frothy and watery with an unpleasant smell. The skin around the vagina and vulva can be uncomfortable, hot and swollen with redness and inflammation that can extend onto the upper thighs. Itching or pain when urinating can also occur.
In males it can cause a discharge from the penis and discomfort when urinating. However, men usually don’t have symptoms of infection.  

Diagnosis

A swab of vaginal fluid can be sent to a laboratory where the organism can be detected by culture or other methods.
Trichomonas in males is very difficult to identify. Male partners of infected females should always be treated.

Trichomoniasis is treated with a course of antibiotic tablets.