infections
Overview of Sexually Transmitted Infections (STIs)
Introduction
Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner. Sexually transmitted disease (STD) refers to a disease that has developed from an STI. Sexually transmitted infections may be caused by bacteria, viruses, or parasites. Some infections can spread to other parts of the body, sometimes with serious consequences. Most sexually transmitted infections can be effectively treated with medications. Using condoms during genital sex can help prevent passing these infections from one person to another. Sexual contact, including oral, anal, or genital sex, provides an opportunity for organisms to spread (be transmitted) from one person to another because it involves transfer of body fluids. Some infections that are spread through sexual contact can also be spread through kissing or close body contact. STIs are relatively common. In the United States, over 25 million new cases of STIs occur each year; about half of the new cases occur in people ages 15 to 24 years (see alsoCenters for Disease Control and Prevention [CDC]: Sexually Transmitted Disease Surveillance 2020). Several factors make prevention of transmission of STIs difficult. They include the following: Unprotected sexual activity with one or more partners Lack of education about safer sex practices Reluctance to talk about safer sex practices with a partner Reluctance to talk about sexual issues with a health care practitioner Lack of access to health care Infections that do not cause symptoms, so people do not know they need to be tested or treated The need to treat both sex partners simultaneously to avoid transmitting the infection between partners again Incomplete treatment, which can lead to development of organisms that are resistant to medications 