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Infectious Diseases. Prevention and Treatment. For teacher’s reference. Curriculum Links : Course: SBI 3C Unit: ( C) Microbiology Expectation: 3.5 - describe how different viruses, bacteria, and fungi can affect host organisms, and how
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Infectious Diseases Prevention and Treatment
For teacher’s reference Curriculum Links: Course: SBI 3C Unit: (C) Microbiology Expectation: 3.5 - describe how different viruses, bacteria, and fungi can affect host organisms, and how those effects are normally treated or prevented (e.g., hepatitis viruses can damage the liver, but vaccinations can prevent infections; streptococcus bacteria can cause respiratory infections, which are treated with antibiotics; ringworm is a fungal infection of the skin, treated with fungicides
Misconceptions Antibiotics can cure all types of infectious diseases Antibiotics can be taken to prevent infections Colds and Flu are caused by bacteria (or general confusion over which illnesses are caused by viruses vs. bacteria) You can get the flu from the flu shot Viruses are living organisms
Agenda Infectious Diseases Bacteria, Viruses, Fungi, and Protists that cause Infectious Diseases Transmission of Diseases Prevention of Diseases Treatment of Diseases
Infectious disease • Defined as: • A disease caused by a microscopic pathogen such as bacteria, viruses, fungi, and parasites • These diseases can be transmitted from person to person
Bacteria and Disease • Bacteria cause disease when they build up in large numbers in an affected area of the body. • The toxins from the bacteria “overload” a person’s immune system and it’s ability to remove these poisons • This can have varying effects on the host (depending on bacteria/disease) • decrease function of cells and tissues • destroying cells and tissues
Examples Adapted from Nelson Biology 11 College Preparation
Viruses and Disease • Viruses depend on host cells to survive and reproduce • Through the process of reproduction, viruses attack host cells • This is what causes the symptoms of the disease • Viral Infections are often difficult to treat Why do you think this is?
Examples How do Viruses compare to Bacteria size wise?
Protists and Disease • Protists which are single celled eukaryotes (examples include amoeba, paramecium) • Protists can be parasitic, causing harm to the host organism • What is meant by parasitic?
Fungi and Disease Fungi are responsible for many human diseases. These diseases are referred to as mycoses Most are simply bothersome Some can be life threatening
Examples • Amanita phalloides(a.k.a Dead cap) world’s most dangerous mushroom. Eating one or two can be fatal
Disease Transmission Infectious diseases can spread easily from person to person in five different ways 1._______________________________ 2._______________________________ 3._______________________________ 4._______________________________ 5._______________________________
Disease Transmission Infectious diseases can spread easily from person to person in five different ways 1. Air 2. Food 3. Water 4. Person to Person contact (direct or indirect) 5. Animal bites
Examples of Transmission Methods Adapted from Modern Biology (2002)
Prevention • Vaccinations • Immune System • Specific • Non-Specific – Body’s “first line of defense” for preventing pathogens from entering the body
Non-Specific Immunity • Skin – keratin shield acts as a barrier • Sweat, oils, and waxes released by skin – toxic to many bacteria and fungi • Mucus membranes – Barrier secretes mucus which traps pathogens • Stomach Acid – destroys most swallowed pathogens • Inflammatory Response – Injured cells send a chemical signal as pathogens enter (through a cut for example). Chemical signal attracts phagocytes to destroy foreign pathogen • Fever – Body’s response to infection
Specific Immunity – The Immune System • Include several organs within the body working together to identify pathogens and kill them • Bone marrow • Thymus • Lymph Nodes • Tonsils • Adenoids • Spleen A great animated video to describe the immune system
Vaccinations • Vaccines contain pathogens or toxins that have been modified so they can no longer cause disease • They contain antigens that stimulate an immune response this produces memory cells • Some diseases that have been controlled through vaccines: • Polio, Measles, Mumps, Tetanus, Diphtheria,
Treatment Different depending on the pathogen causing the disease
Case Study Activity Jessica’s Case Measles Suzie’s Case Malaria Tim’s Case Giardiasis Jack’s Case Cholera
Teaching Strategies/Ideas Graphic organizers (to divide Bacteria, Virus, Protist, and Fungi) Diagnostic activities HIV simulation lab activity Use current/recent events (e.g. H1N1, cholera outbreak in Haiti, SARS) in lessons Incorporate Social Justice (e.g. AIDS awareness, “buy a net” malaria prevention charity)
References http://emedicine.medscape.com/infectious_diseases http://www.microbiologyprocedure.com/infection-and-diseases/diseases-caused-by-bacteria.htm http://www.ehow.com/about_5139239_diseases-do-protists-cause.html http://science.education.nih.gov/supplements/nih1/diseases/guide/understanding1.htm http://www.fungi4schools.org/Documentation/03World-of-Fungi/WF05_Fungi_and_Disease.pdf http://www.phac-aspc.gc.ca/media/nr-rp/2005/2005_3bk1-eng.php