There are several types of sexually transmitted diseases and one of them is Trichomoniasis which is caused by Trichomonas vaginalis. It is very common among women who are sexually active.
Men also get trichomoniasis infection rarely and the symptoms for men irritation in the penis, whitish discharge, burning sensation while passing urine.
In women the infection is asymptomatic (without any symptoms). However some women will have symptoms like vaginal discharge that is green in color, low back pain, discomfort while having sex and vaginal itching.