Trichomoniasis

Trichomoniasis is a sexual trasmitted disease  caused by a parasite. It affects both women and men, but symptoms are more common in women. Symptoms in women include a green or yellow discharge from the vagina, itching in or near the vagina and discomfort with urination. Most men with trichomoniasis don't have any symptoms, but it can cause irritation inside the penis.
You can cure trichomoniasis with antibiotics. In men, the infection usually goes away on its own without causing symptoms. But an infected man can continue to infect or reinfect a woman until he gets treated. So it's important that both partners get treated at the same time. Correct usage of latex condoms greatly reduces, but does not eliminate, the risk of catching or spreading trichomoniasis.

Trichomoniasis is considered the most common curable STD. In the United States, an estimated 3.7 million people have the infection, but only about 30% develop any symptoms of trichomoniasis. Infection is more common in women than in men, and older women are more likely than younger women to have been infected.