1 / 26

Immunity and Infection

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 space such as soil or water

penney
Download Presentation

Immunity and Infection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Immunity and Infection Chapter 17

  2. 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 space such as soil or water • Portal of exit – saliva, mucous membranes, blood, feces, nose • Means of transmission • Direct transmission – sneezing, coughing • Indirect transmission – rats, ticks, mosquitoes • Vectors – carrier of the pathogen from one host to another • Portal of entry • Direct contact with or penetration of the skin • Inhalation through mouth or nose • Ingestion • New host • Breaking the chain at any point can prevent disease

  3. Figure 17.1 The Chain of Infection

  4. The 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 • Memory cells • Antigens and antibodies • “Self” versus “non-self”

  5. Figure 17.2 The Lymphatic System

  6. Inflammatory and Immune Responses • Histamine • Dilation of blood vessels, heat, redness, swelling • The immune responses: natural and acquired • 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 response • Antibody-mediated immune response • Phase 4 – last phase • Slow down activity • Debris excreted from body

  7. Figure 17.3 The Immune Response

  8. Immunity • An infected person may never get the same illness again • Lymphocytes reserved by memory T and B cells = acquired immunity • Symptoms and contagion • Incubation – when 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 – symptoms first appear, but the infected host may have acquired immunity

  9. Epidemics and Pandemics • Epidemic: a rapidly spreading (greater than expected) disease or health-related concern • Pandemic: widespread epidemics • Results only if three criteria are met: • Little or no pre-existing immunity to the new virus • Efficient human-to-human transmission of the virus • New virus can cause illness • May occur in specific populations or regions

  10. 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)

  11. Table 17.2 Immunizations Recommended for Teens and College Students

  12. Immunization Issues • Vaccine shortages in the U.S. • Vaccine safety • Are they really worthwhile?

  13. Allergy: The Body’s Defense System Gone Haywire • Allergies: body defends against harmless substances • Allergens: substances that provoke allergies • Pollen, animal dander, dust mites and cockroaches, molds, food, insects • Allergic response: due to antibody • Immunoglobulin E (IgE) • Anaphylaxis

  14. Figure 17.4 The Allergic Response

  15. Dealing with Allergies • Avoidance • Medication • Immunotherapy or “allergy shots”

  16. Figure 17.5 Pathogens

  17. Pathogens and Disease • Pathogens: bacteria, viruses, fungi, protozoa, parasitic worms, prions • Bacterium – microscopic single-celled organism • Pneumonia • Meningitis • Strep throat and other streptococcal infections • Toxic shock syndrome and other staphylococcal infections • Tuberculosis • Tickborne infections • Ulcers • Other bacterial infections • Tetanus, Clostridium difficile, pertussis, urinary tract infections

  18. Antibiotic Treatment • Actions of antibiotics • Antibiotic resistance • Proper antibiotics usage • Don’t take an antibiotic every time you are sick; effective for bacteria, ineffective for virus • Use antibiotics as directed; finish full course • Never take an antibiotic without an prescription

  19. Viruses • Viruses are parasites – they take what they need • Most common contagious disease • Common cold • Influenza • Measles, mumps, rubella • Chicken pox, cold sores, and other herpesvirus infections • Varicella-zoster virus • Herpes simplex virus (HSV) types 1 and 2 • Epstein-Barr virus (EBV) (causes mononucleosis) • Viral encephalitis • Viral hepatitis (A, B, C) • Poliomyelitis • Rabies • Human papillomavirus (HPV) • Treating viral illnesses

  20. Figure 17.6 Life Cycle of a Virus

  21. Types of Pathogens • Fungi • Primitive plant – yeast infections, athlete’s foot, jock itch, ringworm • Candida albicans • Protozoa • Microscopic single-celled animal: malaria, giardiasis, trichomoniasis, trypanosomiasis, amoebic dysentery • Parasitic worms • Largest organism that can enter the body to cause infection: tapeworm, hookworm, pinworm (most common) • Prions • Fatal degenerative disorders of the CNS linked to “proteinaceous infectious particles” or prions • Lack DNA and RNA • Transmissible spongiform encephalopathies (TSEs) • Spongelike holes in the brain • Creutzfeldt-Jakob disease in humans • Bovine spongiform encephalopathy (BSE) or “mad cow disease” in cattle

  22. Emerging Infectious Diseases • Selected infections of concern: • West Nile virus • Severe acute respiratory syndrome (SARS) • Rotavirus • Escherichia coli 0157:H7 • Hantavirus • Ebola

  23. Factors Contributing to Emerging Infections • Drug resistance • Poverty • Breakdown of public health measures • Travel and commerce • Mass food production and distribution • Human behaviors • Bioterrorism

  24. Other Immune Disorders: Cancer and Autoimmune Diseases • If the immune system breaks down • Getting older • Certain immune disorders (HIV) • Chemotherapy • Autoimmune diseases • Rheumatoid arthritis • Systemic lupus erythematosus

  25. Support Your Immune System How to support your immune system General guidelines Plenty of clean water Avoid contact with vermin Practice safe sex Do not use injectable drugs Vaccinations • Balanced diet • Enough sleep • Exercise • Don’t smoke • Moderation of alcohol • Wash your hands • Avoid contact with contagious people

  26. Chapter 17 Immunity and Infection

More Related