Sexually Transmitted Infections (Cambridge (CIE) IGCSE Co-ordinated Sciences (Double Award)): Revision Note

Exam code: 0654 & 0973

Cara Head

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Cara Head

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STIs & HIV/AIDS

  • Unprotected sexual intercourse can lead to the transfer of pathogens via exchange of body fluids

  • Infections passed on in this way are known as sexually transmitted infections (STIs)

How HIV Affects the Immune System

  • HIV (Human Immunodeficiency Virus) is an example of an STI

  • HIV is a viral pathogen

  • The virus infects the body's immune system and decreases the body’s ability to fight infection, eventually leading to AIDS (Acquired Immunodeficiency Syndrome)

  • HIV can be spread by infected body fluids, e.g.

    • Sharing needles with an infected person

    • Blood transfusions with infected blood

    • From mother to fetus across the placenta during pregnancy

    • Mother to baby via breastfeeding

    • Having unprotected sexual intercourse with a person infected with HIV

Controlling the Spread of STIs

  • The spread of STIs such as HIV is best controlled by:

    • Not having unprotected sex, but making sure to always use a condom

    • Getting tested if unprotected sex or sex with multiple partners has occurred

    • Raising awareness through education programmes

    • Never sharing needles and ensuring medical equipment is sterile

    • Screening for HIV during pregnancy

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Cara Head

Author: Cara Head

Expertise: Biology & Psychology Content Creator

Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding