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KS3: Harmful Microbes

Students are introduced to a number of health issues that can be caused by harmful microbes. This lesson demonstrates the different ways in which bacteria, viruses, and fungi can be pathogenic to humans, and aligns well with PHSE/ RSHE guidelines relating to health & prevention.

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Learning objectives
All students will:
  • Understand that sometimes microbes can make us ill and cause infection
  • Understand that harmful microbes can pass from person to person
  • Understand that different infections cause different symptoms
  • Understand how global travel has influenced the spread of disease
Most students will:
  • Understand how individuals, groups, and organisations work together when responding to infectious diseases outbreaks
Background Information

Some microbes can be harmful to humans and can cause disease: the Influenza virus causes the ‘flu’ (short for ‘Influenza’ – other respiratory tract infections (RTIs) that cause similar symptoms are the ‘common cold’ or ‘influenza-like illness’); Campylobacter bacteria can cause food poisoning; and dermatophyte fungi, such as Trichophyton, can cause diseases such as athlete’s foot and ringworm. Microbes like these are known as pathogens. Each microbe can make us ill in different ways.

Someone who is ill because of a harmful disease-causing microbe is said to be infected. Many harmful microbes can pass from one person to another by a number of different routes – air, touch, water, food, aerosols (such as sneezes and water vapour), animals, etc. Diseases caused by such microbes are said to be infectious diseases.

In this lesson, students explore which microbes cause well known diseases, explore their symptoms, routes of transmission, preventative measures, and potential treatments for each disease.

Main activity:
  • Infectious disease match
Extension activities:
  • Infectious disease discussion
Curriculum links


  • Health and prevention


  • Working scientifically


  • Reading
Supporting Materials
Teacher sheets
KS3 Harmful microbes teacher guidance
TS1 Disease match answers
TS2 Disease match - differentiated answers
Student worksheets
SW1 Disease match worksheet
SW2 Disease match differentiated worksheet
Student handouts
SH1-4 Disease match information sheets
SH5-6 Disease match differentiated information sheets