5.7 - STIs

STIs and how they spread

• A sexually transmitted infection (STI) is an infection passed on through sexual contact, including sexual intercourse.
• The pathogens are carried in the body fluids exchanged during sex, so an STI spreads from an infected person to a partner during unprotected sexual contact.

HIV - A virus

• HIV (human immunodeficiency virus) is spread mainly in infected body fluids such as blood, semen and vaginal fluids during sex.
• It can also be passed on in other ways:
  • Drug users sharing needles
  • From an infected mother to her baby during pregnancy, childbirth or breastfeeding
• An untreated HIV infection may eventually lead to AIDS (acquired immune deficiency syndrome), in which the immune system gradually fails and the person becomes very vulnerable to other infections.

Chlamydia - A bacterium

• Chlamydia is a bacterium and is also passed on during sex.
• It often causes no obvious symptoms, so a person can carry and spread it without knowing.
• If left untreated, it can lead to infertility.

Preventing the spread of STIs

The spread of STIs (sexually transmitted infections) can be reduced in several ways:

• Condoms - Using a condom during sex acts as a barrier that stops body fluids, and the pathogens they carry, being passed between partners.
• Abstinence - Avoiding sexual contact altogether is the only way to be certain an STI is not passed on this way.
• Screening and testing - Finds infections, including ones causing no symptoms, so infected people can be treated and avoid passing the infection on. Testing is especially important after unprotected sex or contact with several partners.
• Medication - Can reduce the chance of an infected person passing the infection on during sex, or of an infected mother passing it to her baby.
• Not sharing needles - People who inject drugs should not share needles, as this passes infected blood between them.