Immunity and Infection Chapter 17

Immunity and infection 2 The Chain of Infection Links in the ChainLinks in the Chain –Transmitted through a chain (six links) Pathogen - disease causing microorganismPathogen - disease causing microorganism Reservoir - natural environment of the pathogen: Person, animal, or environmental componentReservoir - natural environment of the pathogen: Person, animal, or environmental component Portal of ExitPortal of Exit Means of transmissionMeans of transmission –Direct transmission –Indirect transmission Vectors – carrier of the pathogenVectors – carrier of the pathogen from one host to another from one host to another Portal of entryPortal of entry –Penetration of the skin –Inhalation through mouth or nose –Ingestion New hostNew host –Breaking the Chain

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4 Body’s Defense System Physical and Chemical barriersPhysical and Chemical barriers –Skin, mucous membranes, respiratory tract The Immune SystemThe Immune System –Immunological Defenders NeutrophilsNeutrophils Macrophages – “big eaters”Macrophages – “big eaters” Natural killer cellsNatural killer cells Dendritic cells – eat pathogens and activate lymphocytesDendritic cells – eat pathogens and activate lymphocytes LymphocytesLymphocytes –T-cells Helper, Killer, and SuppressorHelper, Killer, and Suppressor –B-cells AntibodiesAntibodies –Memory T and B cells

Identify Body Defenses

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7 The Inflammatory Response Histamine.Histamine. Dilation of blood vessels, heat, redness, and swelling.Dilation of blood vessels, heat, redness, and swelling. The immune responseThe immune response –Phase 1 – Dendritic cells are drawn to the site –Phase 2 – Helper T cells multiply Production of Killer T and B cellsProduction of Killer T and B cells Cytokines – chemical messengersCytokines – chemical messengers –Phase 3 – Killer T cells strike Cell-mediated immuneCell-mediated immune Antibody-mediated immune responseAntibody-mediated immune response –Phase 4 – Last Phase – Suppressor T-cellsSuppressor T-cells Slow down activitySlow down activity

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9 Immunity An infected person will never get the same illness again.An infected person will never get the same illness again. Lymphocytes create amplification of the immune response are reserved by memory T and B cellsLymphocytes create amplification of the immune response are reserved by memory T and B cells Symptoms and contagionSymptoms 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 cycleWill not feel symptoms until the second or third phase of the immune response cycle –Prodromal period – the infected host has acquired immunity

10 Immunization The process of ‘priming’ the body to remember an encounter with a specific antigen.The process of ‘priming’ the body to remember an encounter with a specific antigen. Types of vaccinesTypes 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 Immunization Issues Vaccine shortages in the U.S.Vaccine shortages in the U.S. Vaccine safetyVaccine safety

12 Allergy: The Body’s Defense System Gone Haywire The Body’s Defense System Gone HaywireThe Body’s Defense System Gone Haywire –Allergies –Allergens Pollen, Animal Dander, Dust mites and cockroaches, Molds, Food, InsectsPollen, Animal Dander, Dust mites and cockroaches, Molds, Food, Insects –The Allergic response Immunoglobulin (IgE)Immunoglobulin (IgE) AnaphylaxisAnaphylaxis

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14 Dealing With Allergies AvoidanceAvoidance MedicationMedication Immunotherapy “allergy shotsImmunotherapy “allergy shots

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16 Pathogens and Disease Bacterium – Microscopic single celled organismBacterium – Microscopic single celled organism –Pneumonia –Meningitis –Strep Throat and other streptococcal infections –Toxic shock and other staphylococcal –Tuberculosis –Tickborne infections –Ulcers –Other Bacterial infections TetanusTetanus PertussisPertussis Urinary tract infectionsUrinary tract infections

17 Antibiotic Treatment Actions of AntibioticsActions of Antibiotics Antibiotic resistanceAntibiotic resistance Proper antibiotics usageProper antibiotics usage –Don’t take an antibiotic every time you are sick –Use antibiotics as directed –Never take an antibiotic without an prescription

18 Type of Pathogens Viruses – (parasites – take what they need)Viruses – (parasites – take what they need) Most common contagious diseaseMost common contagious disease –Common Cold –Influenza –Measles, Mumps and Rubella –Chickenpox, Cold Sores, and other herpes-virus infections Varicella-zoster virusVaricella-zoster virus Herpes simplex virus (HSV) types 1 and 2Herpes simplex virus (HSV) types 1 and 2 Epstein-Barr virus (EBV)Epstein-Barr virus (EBV) –Viral encephalitis –Viral hepatitis –Poliomyelitis –Rabies –Human papillomavirus (HPV) TreatmentTreatment

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20 Types of Pathogens Fungi –Fungi – –Primitive plant – Yeast infections, athletes foot, jock itch, and ringworm –Candida albicans Protozoan –Protozoan – –Microscopic single-celled animal – Malaria, African sleeping sickness, Giardiasis, Tricomonias, Trypanosomiasis, and Amoebic dysentary. Parasitic worm –Parasitic worm – –Largest organism that can enter the body – Tapeworm, Hookworm, and Pinworm. Prions –Prions – –Fetal degeneration disorders of the CNS, linked to “proteinaceous infectious particles. –Lack DNA and RNA –Transmissible spongiform encephalopathies (TSEs) Spongelike holes in the brainSpongelike holes in the brain Creutzfeldt-Jakob disease – HumanCreutzfeldt-Jakob disease – Human –Bovine spongiform encephalopathy (BSE) or mad cow disease

21 Emerging Infectious Diseases Selected Infections of concernSelected Infections of concern –West Nile virus –Severe acute respiratory syndrome (SARS) –Rotavirus –Escherichia coli 0157:H7 –Hantavirus –Ebola

22 Factors Contributing to Emerging Infections Drug ResistanceDrug Resistance PovertyPoverty Breakdown of public health measuresBreakdown of public health measures Environmental changesEnvironmental changes Travel and CommerceTravel and Commerce Mass food production and distributionMass food production and distribution Human behaviorsHuman behaviors BioterrorismBioterrorism

23 Other Immune Disorders: Cancer and Autoimmune Diseases If the immune system breaks downIf the immune system breaks down Getting olderGetting older HIV infectionHIV infection ChemotherapyChemotherapy Autoimmune diseasesAutoimmune diseases –Rheumatoid arthritis –Systemic lupus erythmatosus

Support Your Immune System How to support your immune system General guidelines Balanced dietBalanced diet Enough sleepEnough sleep ExerciseExercise Don’t smokeDon’t smoke Moderation of alcoholModeration of alcohol Wash your handsWash your hands Avoid contact with contagious peopleAvoid contact with contagious people Plenty of clean waterPlenty of clean water Avoid contact with verminAvoid contact with vermin Practice safe sexPractice safe sex Do not use Injectable drugsDo not use Injectable drugs VaccinationsVaccinations Controlling StressControlling Stress 24