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

Pathogens & prevention of diseases

• Pathogens are:

microorganisms that cause infectious disease

• Diseases caused by pathogens can be transmitted between individuals in a population; they are said to be communicable

• Types of pathogen include:

  • bacteria

  • viruses

  • fungi

  • protists

• Both plants and animals can be infected by pathogens

Controlling the spread of disease

• Transmission can occur either through:

  • direct contact

  • contaminated water

  • droplets carried in the air

• Reducing the spread of pathogens can aid disease control

Methods to prevent spread of pathogens

• Hygienic food preparation to prevent contact transmission, including:

  • 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

  • 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 number of individuals that can transmit a pathogen

• Destruction of vectors that carry the disease can reduce transmission

  • Find out more about protist diseases that require vectors