Communicable diseases, disease prevention and the immune system (4.1.1)
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Delivery guides are designed to represent a body of knowledge about teaching a particular topic and contain:
- Content: a clear outline of the content covered by the delivery guide
- Thinking Conceptually: expert guidance on the key concepts involved, common difficulties students may have, approaches to teaching that can help students understand these concepts and how this topic links conceptually to other areas of the subject
- Thinking Contextually: a range of suggested teaching activities using a variety of themes so that different activities can be selected that best suit particular classes, learning styles or teaching approaches.
Content (from AS and A-level)
The content from the specification that is covered by this delivery guide is:
|4.1.1 Communicable diseases, disease prevention and the immune system|
|(a)||the different types of pathogen that can cause communicable diseases in plants and animals||To include:
• bacteria – tuberculosis (TB), bacterial meningitis, ring rot (potatoes, tomatoes)
• viruses – HIV/AIDS (human), influenza (animals), Tobacco Mosaic Virus (plants)
• protoctista – malaria, potato/tomato late blight
• fungi – black sigatoka (bananas), ringworm (cattle), athlete’s foot (humans).
|(b)||the means of transmission of animal and plant communicable pathogens||To include direct and indirect transmission, reference to vectors, spores and living conditions e.g. climate, social factors (no detail of the symptoms of specific diseases is required).
M0.1, M0.2, M0.3, M1.1, M1.2, M1.3, M1.5, M1.7, M3.1, M3.2
HSW1, HSW2, HSW3, HSW5, HSW6, HSW7, HSW8, HSW11, HSW12
|(c)||plant defences against pathogens||To include production of chemicals
plant responses that limit the spread of the pathogen (e.g. callose deposition).
|(d)||the primary non-specific defences against pathogens in animals||Non-specific defences to include skin, blood clotting, wound repair, inflammation, expulsive reflexes and mucous membranes (no detail of skin structure is required).
|(e)||(i) the structure and mode of action of phagocytes
(ii) examination and drawing of cells observed in blood smears
|To include neutrophils and antigen-presenting cells
the roles of cytokines, opsonins, phagosomes and lysosomes.
|(f)||the structure, different roles and modes of action of B and T lymphocytes in the specific immune response||To include the significance of cell signalling (reference to interleukins), clonal selection and clonal expansion, plasma cells, T helper cells, T killer cells and T regulator cells.
|(g)||the primary and secondary immune responses||To include T memory cells and B memory cells.
|(h)||the structure and general functions of antibodies||To include the general structure of an antibody molecule.|
|(i)||an outline of the action of opsonins, agglutinins and anti-toxins|
|(j)||the differences between active and passive immunity, and between natural and artificial immunity||To include examples of each type of immunity.|
|(k)||autoimmune diseases||To include an appreciation of the term autoimmune disease and a named example e.g. arthritis, lupus.|
|(l)||the principles of vaccination and the role of vaccination programmes in the prevention of epidemics||To include routine vaccinations
reasons for changes to vaccines and vaccination programmes (including global issues).
M0.1, M0.2, M0.3, M1.1, M1.2, M1.3, M1.5, M1.7, M3.1, M3.2
HSW1, HSW2, HSW3, HSW5, HSW6, HSW7, HSW8, HSW9, HSW11, HSW12
|(m)||possible sources of medicines||To include examples of microorganisms and plants (and so the need to maintain biodiversity)
the potential for personalised medicines and synthetic biology.
HSW7, HSW9, HSW11, HSW12
|(n)||the benefits and risks of using antibiotics to manage bacterial infection.||To include the wide use of antibiotics following the discovery of penicillin in the mid-20th century
the increase in bacterial resistance to antibiotics (examples to include Clostridium difficile and MRSA) and its implications.
HSW2, HSW5, HSW9, HSW12
This is based on the old ‘Name That Tune’ game show. It’s a fun way of introducing a topic whilst giving the crucial pieces of information. With diseases that students may not have heard of, the words can be used as clues e.g. Tobacco Mosaic Virus: ‘Part of my name may be associated with cigarettes.’
It can be used in a simple form or as a tool to introduce more facts as the learning progresses. The diseases can be listed on the board and students then pick the right disease for the facts being read or students could be allowed to guess the disease solely from the fact cards. As with the game show, the fewer facts required to guess the pathogen, the more points the student achieves (or they win outright). Students could even suggest how many facts they could name it in before the facts are read/revealed.
Example – TB:
- I was discovered by Robert Koch in 1882
- The discovery of antibiotics in 1944 helped halt my spread
- Gram staining does not work on me
- I am a bacterium that survives inside cells
- I cause breathing problems
- I am phagocytosed by macrophages in the lungs
- A vaccine exists to protect against me, called BCG.
This is a simple mix and match activity where students have to match a particular social situation or condition with a particular disease. This can be text or visual, the latter tending to be more effective. It can be extended to include diseases that are topical or relevant to a particular class and not just confined to the examples given in the specification.
Mix and match card examples are suggested below.
- Squalid conditions (taken from a less economically developed country or from history in UK) for cholera/typhoid
- Winter scene for influenza
- Rainy weather for potato blight
- Tropical picture with mosquitoes for malaria
- Sharing of dirty needles for HIV/AIDS.
See the link 'Infectious diseases' for a website which is a good starting point for facts behind each disease.
Here are a couple of suggested practical activities from SAPS that could link in to the teaching of communicable diseases in plants:
CSI Trees – investigating plant pathogens
Deadly diseases and plant pathology.
Approaches to teaching the content
These learning outcomes are designed to demonstrate the constant ‘battle’ between the immune system and pathogens. They also demonstrate the diversity of the pathogenic world (a good link with 4.2.2 Classification) and the routes the immune system has to take to overcome them and indeed how the immune system is exploited by the pathogen. This is an on-going battle that is followed through the learning outcomes and concludes with the need to understand that this battle is continuing to this day, with the increase in bacterial antibiotic resistance (4.1.1n) and the search for botanical sources of medicine (4.1.1m). This links well with learning outcomes 4.2.2(h) and (i) and the concept of pathogen evolution can be discussed here.
This whole topic can be seen as a walk through biological history as well as clear biological content as shown in the activity ‘Swimming through the rivers of history’. A particular epidemic can be discussed in terms of its geography and other patterns of its history and each is linked to particular learning outcomes in this topic e.g. ‘US soldiers returning from (the First World) War in large numbers were susceptible to influenza’ can be linked with 4.1.1(b), (d) and (g) (and taken further if desired).
Common misconceptions or difficulties students may have
The use of specific examples of epidemics/pathogens can be used throughout the teaching. Examples of pathogens and their antigens are a good way of navigating students through the complexity of antigen presentation, clonal selection etc. for B and T cells (4.1.1e–f). Many students find it difficult to visualise these processes and their chronology, so taking a specific antigen and showing how it travels through the body and ‘selects’ a particular lymphocyte can aid this understanding (see the ‘Thanks for the memories’ activity).
The importance of the antibody can be easily linked to the concepts behind this topic but the structure (4.1.1h) can cause confusion e.g. how many polypeptide chains each antibody has and how the hinge region works. This can easily be remedied by using pipe cleaners and asking students to assemble their own antibodies (see the ‘Capture the antigen’ activity). This can be used to highlight the fact that each antibody from one particular B cell has a set variable region, as students often see antibodies as changing their variable regions or a B cell as producing a wide variety of antibodies.
Conceptual links to other areas of the specification – useful ways to approach this topic to set students up for topics later in the course
4.1.1 Communicable diseases, disease prevention and the immune system has many synoptic links with the earlier teaching Module 2: Foundations in biology, particularly 2.1.1 Cell structure, and 2.1.5 Biological membranes. 4.1.1 therefore gives teachers a chance to reinforce earlier theory and skills e.g. the use of a light microscope with 4.1.1e (ii) blood smears.
4.1.1 Communicable diseases, disease prevention and the immune system also has a clear link with the later topics within this teaching Module – 4.2.1 Biodiversity and 4.2.2 Classification and evolution. A teacher may therefore wish to introduce, or fully incorporate, some of those topics whilst delivering 4.1.1.
Few students have encountered autoimmune diseases (4.1.1k) and those that have commonly discuss them in terms of being automatic diseases that the immune system responds to quickly. This can be linked with other areas of the specification e.g. 5.1.4(e) for Type 1 diabetes or 5.1.2(c and e) for Goodpasture’s Syndrome or glomerulonephritis. This is outlined in a webpage from the 'National institute of Diabetes and Digestive and Kidney Diseases' from the U.S. (see link 'Goodpasture’s Syndrome').
This is a timeline style activity, which can be added to as the teaching of 4.1.1 progresses. It is designed to be used throughout the teaching of the content and then works well as a revision tool. It is a great way of using literacy and social awareness within the context of Biology.
This can easily be repeated with TB, HIV and malaria. This also works well with potato blight, which can be tied with the Irish potato famine of 1845.
See the link for information on the Irish potato famine.
4.1.1 Communicable diseases, disease prevention and the immune system can be taught with reference to specific historical examples of disease outbreaks throughout all the learning outcomes, as outlined in the activity ‘Swimming through the rivers of history’.
The less historically active pathogens – for example, athlete’s foot – can be discussed in a medical context and linked with epidemiological data and good visual pictures.
Indeed, epidemiological data can be used throughout the learning outcomes and are particularly useful for 4.1.1(g) and (l). This also links to mathematical skills e.g. M1.3, M3.1.
Eurosurveillance is a good website showing bar chart data for the 2009 influenza outbreak.
Pictures of various diseases/immune cells can be used and mix and match activities utilised throughout the learning outcomes with pictures being matched with the correct nomenclature (see the ‘Spreading the germs’ activity). Pictures of antigen presenting cells and phagocytes are good to show, as well as microscope slides, and can be contrasted with each other to illustrate the specialisation of each cell type (4.1.1e).
Some learning outcomes require a clear sequence of events and these can be introduced or revised using sequence cards (see the ‘Thanks for the memories’ activity) where each student has a sequence card and must stand up or role play at the correct time in the sequence of events. This works well for 4.1.1(e) and (f).
Models can be used to illustrate the structure of an antibody, which can be done as a team task with each student having one component and having to construct the antibody, or as an individual activity (see the ‘Capture the antigen’ activity).
The ‘fun’ element of the topic can be introduced with areas that students often pay minimal attention to and thus forget. This is demonstrated for 4.1.1(d) in the activity ‘What’s bugging you?’.
One student can take on the role of a pathogen or antigen (e.g. H1N1 for influenza virus) and then they have to navigate around the classroom in the correct sequence, where other members of the class have cards or pictures to show what they represent in the body. Students can be placed in the correct order and the ‘pathogen’ student has to guess what they are or students can be randomly placed showing their cards and the ‘pathogen’ has to find the correct student at each stage. The pathogen student can go through the whole sequence or hand over to a ‘B cell/T cell’ student who can continue the process.
The website 'New Human Physiology' has a webpage which summarises clonal expansion (see link).
Influenza virus/H1N1 antigen
Bronchial epithelial cells
Dendritic cells/macrophage/antigen presenting cell
Blood plasma/lymph fluid
Naïve B cells/naïve T cells
Complementary B cell receptor/T cell receptor to antigen
Development of specific B lymphobasts/T lymphoblasts in clonal selection
Mitosis of lymphoblasts for clonal expansion
Differentiation of cloned lymphocytes
Plasma cells/Effector T cells
Memory B cells/Memory T cells
Antibodies to lungs/Killer T cells and Helper T cells to lungs.
This is a simple activity to outline the structure of the antibody (4.1.1h). It can be combined with shapes representing antigens of varying structure and used to demonstrate the antibodies roles as opsonins, agglutinins and anti-toxins (4.1.1i).
Each student has three different coloured pipe cleaners representing the disulfide bonds, heavy chains and light chains. The heavy chain pipe cleaner is cut into four, the light chain pipe cleaner is cut into two and the disulfide bond pipe cleaner is cut into four. Students then join the pipe cleaners with or without assistance (good differentiation tool) and then the variable regions can be twisted to fit various shaped antigens. Each student can represent a B cell, producing one type of antibody, and this can be used to illustrate this fact, which students often fail to grasp. Toxins can be introduced using modelling clay and the pipe cleaner antibody used to demonstrate its role as an antitoxin. This is a good way of allowing students to explore the possible actions of antibodies prior to teaching 4.1.1(i).
Students are given a fun bug that attacks different parts of the body or allow students to name their own bug when given a particular part of the body or condition. Students then have to suggest how the body attempts to remove that bug prior to the involvement of the innate/acquired immune response.
- Bug Bazooka was in your curry; how will you get rid of it?
- Bug Winterola is around in this cold weather; how do you get rid of it?
- Bug Cuttoba is on that rusty knife; how will you stop it getting into your body?
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