What are sexually transmitted infections?

The pathogens causing sexually transmitted infections are mainly transmitted through and/or affect the penis and the vagina as well as the rectum. They are most commonly passed on through body fluids that play a role during sex, such as semen, the liquid film on the mucous membranes of the vagina, penis and rectum, and through blood. The main routes of transmission are vaginal and anal intercourse without a condom or internal condom as well as oral intercourse.

Most sexually transmitted infections are easily treatable if diagnosed early on. If left untreated, some of them can have severe consequences, such as infertility, loss of eyesight (as a result of untreated gonorrhoea of the eyes), or damage to blood vessels, bones, nerves, or the brain (in advanced syphilis).