Sexually transmitted disease
Trichomoniasis is the most common STD in the world that is not caused by a virus.  It can cause inflammation swelling of the vagina (vaginitis, urethra (urethritis), or penis.  It can also cause more serious problems.  If it is not treated, it can cause permanent damage to a woman's reproductive system.  It can also cause prostate cancer, and makes a woman more likely to give birth to a premature baby.