• A sexually transmitted infection (STI) is an infection that spreads through sexual contact.
  • STIs are caused by pathogens, a living thing or virus that causes infection.
  • The only way to avoid the risk of STIs is to practice abstinence from sexual activity.
  • Only some STIs can be cured with medicine; other STIs cannot be cured.
  • Rates of chlamydia among U.S. females in 2006 are shown below.
  • Rates were much higher in teens and young women than in other age groups.
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