Are you confused by the difference between an STI and an STD? You're not alone.

An STI is a sexually transmitted infection. More than 1 million STIs are passed along every day worldwide, according to the World Health Organization (WHO). The Centers for Disease Control and Prevention (CDC) estimates that adolescents and young adults account for half of all new sexually transmitted infections.

A sexually transmitted infection often leads to a sexually transmitted disease (STD). Some organizations use these terms interchangeably, but they are different. Simply put, an STI is an infection that has not yet developed into a disease. As the term indicates, STIs are transmitted during sexual activity and can include infections from parasites, bacteria or viruses.

When STIs are not treated, and bacteria, viruses or parasites begin exhibiting symptoms, they become sexually transmitted diseases and may cause permanent damage to