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  • We all get sick from time to time. Wintertime, in particular, brings with it colds and flus.

    Symptoms may include feeling hot and cold, a runny nose, streaming eyes, headaches, tiredness, loss of appetite, then after a few days (or sometimes longer), we start to feel better and are back to normal. So what is happening? Why do we feel so terrible? How do we get better? What is going on inside our bodies?

    Let’s investigate…

    Infection is the invasion of pathogenic (disease-causing) microorganisms in the body and the body’s response to that.

    Pathogenic microorganisms, commonly called germs or bugs, are all around us. They can be easily transmitted from one person to another. Once they get past your skin (part of your first line of defence), they get into your body, your bloodstream and your cells. At this point, your immune system (your second line of defence) kicks in and fights back to destroy the pathogens causing infection.

    The immune system

    The immune system consists of cells, tissues and organs that work together to protect you. We explore the immune system and how it responds to various microorganisms.

    In the article The body’s second line of defence, we look at microorganisms, including some of the pathogens that cause sickness.

    Hand washing and hygiene practices are vital to stopping the spread of infection. In the 1880s, Florence Nightingale was well aware of the importance of hand washing even though microorganisms were not fully understood at that time.

    Every nurse ought to be careful to wash her hands very frequently during the day. If her face, too, so much the better.”

    Florence Nightingale

    We find out what happens when your immune system doesn’t work through the story of David Vetter who lived in a sterile bubble all his life.

    We also take a look at vaccination. This is a way of preventing some diseases by using your immune system to protect you. Vaccination became a global focus with the COVID-19 pandemic. We look at the history of vaccination, as well as current immunisation in New Zealand. This is supported by activities including an investigation into some of the ethical issues surrounding vaccination.

    Māori perspectives

    We explore rongoā – the Māori term for medicines that are produced from native plants in New Zealand. Many of these plants were and are still used to fight infection. Find out more in the article Rongoā Māori and then follow up with the activity Using rongoā Māori.

    Meet the scientists

    Scientists from the Malaghan Institute of Medical Research in Wellington share their research. The article Hookworm and allergies profiles the work of Professor Graham Le Gros, who is working on a vaccine against asthma and allergies. Dr Joanna Kirman explores infectious diseases, like tuberculosis, and how they affect the immune system. This helps her team find cures for these diseases. Dr Bridget Stocker and Dr Mattie Timmer design drugs and make molecules to improve vaccines.

    Take up the challenge

    We also have some great activity ideas that cover some of the big ideas in science.

    There are also cross-curricular opportunities: Literacy in immunology and Drama with microbes.

    Curious to see how all of this fits together? Check out the unit plans: Fighting infection – the immune system and Fighting infection – reducing infection.

    Being a scientist is a lot like being a detective – you have to think of cunning ways to solve problems and find the answers.

    Dr Joanna Kirman (Malaghan Institute of Medical Research)

    Question bank

    The Fighting infection – question bank provides a list of questions about ferns and places where their answers can be found. The questions support an inquiry approach.

    Key terms

    For explanations of key concepts, see Fighting infection – key terms.


    Use this timeline to see some of the historical aspects of fighting infection, covering early discoveries on germs, vaccination, how are our bodies help us to get better and more.


    We have curated content in this Viruses and the immune system collection – it explores viruses and how our immune system fights them. Log in to make this collection part of your private collection. Click on the copy icon, and then you can add additional content and notes and make other changes.

      Published 2 November 2010 Referencing Hub articles
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