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Transcript
Immunity and Infection Chapter 17 The Chain of Infection • Links in the Chain – Transmitted through a chain (six links) • Pathogen - disease causing microorganism • Reservoir - natural environment of the pathogen: Person, animal, or environmental component • Portal of Exit • Means of transmission – Direct transmission – Indirect transmission • Vectors – carrier of the pathogen from one host to another • Portal of entry – Penetration of the skin – Inhalation through mouth or nose – Ingestion • New host – Breaking the Chain Immunity and infection 2 3 Body’s Defense System • Physical and Chemical barriers – Skin, mucous membranes, respiratory tract • The Immune System – Immunological Defenders • • • • • Neutrophils Macrophages – “big eaters” Natural killer cells Dendritic cells – eat pathogens and activate lymphocytes Lymphocytes – T-cells • Helper, Killer, and Suppressor – B-cells • Antibodies – Memory T and B cells 4 Identify Body Defenses 6 The Inflammatory Response • Histamine. • Dilation of blood vessels, heat, redness, and swelling. • The immune response – Phase 1 – Dendritic cells are drawn to the site – Phase 2 – Helper T cells multiply • Production of Killer T and B cells • Cytokines – chemical messengers – Phase 3 – Killer T cells strike • Cell-mediated immune • Antibody-mediated immune response – Phase 4 – Last Phase – • Suppressor T-cells • Slow down activity 7 8 Immunity • An infected person will never get the same illness again. • Lymphocytes create amplification of the immune response are reserved by memory T and B cells • Symptoms and contagion – Incubation – viruses are multiplying in the body or when bacteria are actively multiplying • Will not feel symptoms until the second or third phase of the immune response cycle – Prodromal period – the infected host has acquired immunity 9 Immunization • • The process of ‘priming’ the body to remember an encounter with a specific antigen. Types of vaccines – VACCINE- Introduction of a killed or weakened – – – pathogen to stimulate the body to produce antibodies. ACTIVE IMMUNITY - person produces his or her own antibodies to the microorganism. PASSIVE IMMUNITY- Injection of antibodies produced by other human beings or animals. ACQUIRED IMMUNITY-The ability of a memory lymphocytes to remember a previous infection. (chicken pox). 10 Immunization Issues • Vaccine shortages in the U.S. • Vaccine safety 11 Allergy: The Body’s Defense System Gone Haywire • The Body’s Defense System Gone Haywire – Allergies – Allergens • Pollen, Animal Dander, Dust mites and cockroaches, Molds, Food, Insects – The Allergic response • Immunoglobulin (IgE) • Anaphylaxis 12 13 Dealing With Allergies • Avoidance • Medication • Immunotherapy “allergy shots 14 15 Pathogens and Disease • Bacterium – Microscopic single celled organism – – – – – – – – Pneumonia Meningitis Strep Throat and other streptococcal infections Toxic shock and other staphylococcal Tuberculosis Tickborne infections Ulcers Other Bacterial infections • Tetanus • Pertussis • Urinary tract infections 16 Antibiotic Treatment • Actions of Antibiotics • Antibiotic resistance • Proper antibiotics usage – Don’t take an antibiotic every time you are sick – Use antibiotics as directed – Never take an antibiotic without an prescription 17 Type of Pathogens • Viruses – (parasites – take what they need) • Most common contagious disease – – – – Common Cold Influenza Measles, Mumps and Rubella Chickenpox, Cold Sores, and other herpes-virus infections • Varicella-zoster virus • Herpes simplex virus (HSV) types 1 and 2 • Epstein-Barr virus (EBV) – – – – – Viral encephalitis Viral hepatitis Poliomyelitis Rabies Human papillomavirus (HPV) • Treatment 18 19 Types of Pathogens • Fungi – – Primitive plant – Yeast infections, athletes foot, jock itch, and ringworm – Candida albicans • Protozoan – – Microscopic single-celled animal – Malaria, African sleeping sickness, Giardiasis, Tricomonias, Trypanosomiasis, and Amoebic dysentary. • Parasitic worm – – Largest organism that can enter the body – Tapeworm, Hookworm, and Pinworm. • Prions – – Fetal degeneration disorders of the CNS, linked to “proteinaceous infectious particles. – Lack DNA and RNA – Transmissible spongiform encephalopathies (TSEs) • Spongelike holes in the brain • Creutzfeldt-Jakob disease – Human – Bovine spongiform encephalopathy (BSE) or mad cow disease 20 Emerging Infectious Diseases • Selected Infections of concern – – – – – – West Nile virus Severe acute respiratory syndrome (SARS) Rotavirus Escherichia coli 0157:H7 Hantavirus Ebola 21 Factors Contributing to Emerging Infections • • • • • • • • Drug Resistance Poverty Breakdown of public health measures Environmental changes Travel and Commerce Mass food production and distribution Human behaviors Bioterrorism 22 Other Immune Disorders: Cancer and Autoimmune Diseases • If the immune system breaks down • Getting older • HIV infection • Chemotherapy • Autoimmune diseases – Rheumatoid arthritis – Systemic lupus erythmatosus 23 Support Your Immune System How to support your immune system General guidelines • • • • • • • Balanced diet Enough sleep Exercise Don’t smoke Moderation of alcohol Wash your hands Avoid contact with contagious people • • • • Plenty of clean water Avoid contact with vermin Practice safe sex Do not use Injectable drugs • Vaccinations • Controlling Stress 24