8 - Infections and Defects in Mechanisms of Defense Flashcards
Communicability
Ability to spread from one person to another and cause disease
Infectivity
Pathogen’s ability to invade and mulitply in host
Virulence
Severity or harmfullness of a disease or poison
Toxigenicity
Ability to produce toxins (influences a pathogen’s virulence)
Portal of entry
Route by which a pathogen infects host
Prokaryotes
Lack nucleus, +/- O2, Gram +/- (gram- is more dangerous (outer membrane, porin channels)
Staphylococcus aureus
-Life threatenening, very virulent (resist phagocytosis, protien blockers, inhibit recognition by immune system)
-common nosocomial infection, common on normal skin and nasal passages
-Resist many antibiotics
Exotoxins
-Released from inside of pathogen
-damage host cell plasma membranes or interfere with protien synthesis
Endotoxins
Released from outer capsule
-activate inflammatory response, produce fever
Bacteremia
Presence of bacteria in blood
Septicemia
growth of bacteria in blood
Viral disease
-Most commong affliction of humans
-to replicate they must enter host cell, as such are self-limiting
-simple organism (DNA/RNA surrounded by Capsid envolope)
Cytopathic
Causing damage to living cells
Antigenic variation
ability to change viral antigen (spikes) yearly, results in dysfunction in adaptive immune response
E.g. seasonal flu
Fungal Infection
Eukaryotes, resist penicillin, simple division reproduction
Mycoses
Diseases caused by funghi
Dermatophytes
Funghi that invade skin, hair or nails
Tineas
Term for diseases caused by dermatophytes
E.g. tinea capitis (scalp infection)
Candida albicans
Most common cause of fungal infection
-found in normal human microbiome (skin, vagina, GI)
-Disseminated in immunocompromised, high mortality rates (30-40%)
Disseminated
Spread (on same person)
Parasitic Infections
-caused by unicellular protazoa
-Spread via vectors or contaminated food/water
Plasmodium malariae
Causes (malaria)
-occurs in RBCs, anemia within 48-72 hours
-RBC release cytokines (TNF-a/IL-1) = fever, chills, vomiting
Bactericidal
agent that kills other microorganisms
Bacteriostatic
agent that inhibts growth of other microorganisms
What has contributed to antibiotic Resistance?
-lack of compliance with therapeutic regimen
-overuse of antibiotics
Toxoids
Chemically altered pathogen toxin injected into body, allows body to learn to defeat that toxin
Passive immunotherapy
Preformed antibodies are given to individual, obtained from human immunoglobin from pathogen survivor
Primary Immune Deficiency
Congenital immunodeficiency caused by gentic defect
Secondary Immunodeficiency
Acquired immunodeficiency caused by another illness
-more common than primary but usually less severe (exception of AIDS and cancer)
E.g. cancer
Severe Combined Immunodeficiency (SCID)
Underdelvoped thymus leads to absense of T-cells, few lymphocytes
DiGeorge Syndrome
Thymus and parathyroid gland dysfunction,
leads to inadequate T-cell production and management of plasma calcium
Hypogammaglobulinemia
Result from defect in B-cell maturation or function, results in lower levels of circulating immunoglobulins (antibodies) in blood
Complete Blood Count (CBC)
Numbers of RBC, WBC, platelets
Differential
Individual numbers of lymphocytes, granulocytes and monocytes
Quantitative determination of immunoglobins
Determines subpopulations of immunoglobins
Total Complement Assay
Total number of complements in blood
Stem Cell Transplantation
-transplant from bone marrow, umbiullical cord cells, temporary improvement
Mesenchymal stem cell (MSCs) injection
Injection of undifferentiated stem cells found in bone marrow, they undergo differentiation into other cell types
-potent immunosuppressive properties
Gene Therapy
Therapeutic replacement of defective genes
–> reconsititution of immune system
but can lead to leukemia in some recipients
Acquired Immune Deficiency Syndrome (AIDS)
-Caused by Human Immunodeficiency Virus (HIV)
-Depletes Helper T-cells –> dysfunctional afaptive immune system, increased susceptibility to disease
Epidemiology
branch of medicine that deals with incidence, distribution, and possible control of diseases
Difficulties with HIV vaccine development (2)
-HIV is genetically and antigenically variable
-HIV+ people have high levels of antibodies, but are not protective –> even if a vaccine creates antibodies they likely will not function properly
Anti-retroviral therapy (ART)
Combination drug therapy that inhibits entrance, reverse transcriptase, integrase and protease
Retroviral
Virus with RNA not DNA
Hypersensitivity
Altered immunological reponse to an antigen that results in disease or damage to host
Allergy
Harmful effects of hypersensitivity to environmental antigens
Autoimmunity
Disturbance in immunological tolerance of self-antigens
clinical disorders are called autoimmune diseases
Alloimmunity
Immune reacion to tissues of another individual (transplants, transfusions, or fetus)
Type I Hypersensitivity
IgE mediated (+histamine)
-most common, against enviromental antigens
-includes inital exposure (sensitization) and the subsequent exposure –> release of cytokines creates hypersensitive reaction
E.g. hay fever
Type II Hypersensitivity
Tissue-specific reactions (also called Cytotoxic Hypersensitivity)
-antibody mediated destruction of healthy host cells, against a specific tissue (only attatch to specific plasma membranes)
E.g. hemolysis in medication allergies
Type III Hypersensitivity
Immune complex mediated
Immune complexes formed and deposited in tissues, later attatch to cells
E.g. gluten allergy
Type IV Hypersensitivity
Cell mediated (Does not involve antibodies)
E.g. poison ivy, graft rejection
Immediate Hypersensitivity Reaction
reaction that occurs within minutes or hours
Anaphylaxis
Most rapid and severe immediate immune reaction
Symptoms are pruritis, erythema, vomiting, diarrhea, breathing difficulties
Pruritis
Severe itching
Erythema
Red patches on skin
Delayed Hypersensitivity Reacion
Reaction occurs after serveal hours to maxium of several days later
Atopic
Individuals predisposed to developing allergies
one parent = 40% of offspring have allergy
both parents = up to 80% of offspring
Graves’ Disease
Type II Hypersensitvitiy,
-Antibodies target cell malfunction –> targets thyroid, doesn’t kill cells but causes malfunctions
Herd Immunity
General protection of a population form a disease by means of majority protection rather than individual protection. Requires 85% of population immunized
