Communicable (Infectious) Diseases (AQA GCSE Biology): Revision Note

Pathogens & prevention of diseases

What is a communicable disease?

• A disease is an illness or disorder of the body or mind that leads to poor health

• Communicable/infectious diseases are caused by pathogens and are transmissible (can be spread between individuals within a population)

  • Both plants and animals can be affected by pathogens

Infectious and non-infectious diseases table

• Many microorganisms are pathogens including:

  • Bacteria

  • Viruses

  • Fungi

  • Protists

• To control disease, it is very important to know what pathogen is causing it

Controlling the spread of disease

• Transmission occurs either through direct contact, contaminated water or in droplets carried in the air

• The simplest way to prevent disease is to stop pathogens from spreading

• Controlling the spread of disease can be done through:

  • good hygiene

  • effective sanitation 

  • waste disposal

Methods to prevent spread of pathogens

• Hygienic food preparation to prevent contact transmission:

  • keep food cold to slow bacteria and fungi reproduction

  • wash hands and clean surfaces to avoid contamination

  • cook food thoroughly to kill pathogens

  • use separate utensils for uncooked meat and cover food to prevent contamination

• Personal hygiene

  • To prevent direct transmission:

    • wash with soap, especially after using the bathroom, to remove pathogens

  • To prevent airborne transmission:

    • use tissues to catch sneezes and coughs and dispose of used tissues

• Waste disposal to prevent direct transmission:

  • dispose of waste food to prevent prevalence of flies which act as a vector

  • cover rubbish bins and remove to the landfill for disposal or burning regularly

• Sanitation to prevent waterborne transmission:

  • homes and public places should have plumbing and drains to remove faeces and waste safely; these drains can carry pathogens

  • raw sewage should be treated to remove solid waste and kill pathogens before being released into the environment

Other methods to reduce transmission in the population

• Vaccinations reduce the likelihood of transmission

• Destroying vectors that carry the disease

  • Find out more about protist diseases that require vectors