FUNDA INFECTION CONTROL

• WHAT ARE THE TWO TYPES OF INFECTION?

  1. EXOGENOUS
  2. ENDOGENOUS
• WHAT IS THE INFECTION FROM THE ENVIRONMENT?

  EXOGENOUS
• WHAT IS THE INFECTION THAT ORIGINATE FROM THE INSIDE OF AN ORGANISM

  ENDOGENOUS
• WHAT ARE MODES OF TRANSMISSION?

  1. DIRECT / CONTACT TRANSMISSION
  2. INDIRECT TRANSMISSION (VEHICLE/VECTOR)
  3. AIRBORNE TRANSMISSION
• How do direct/contact transmission spread?

  • Physical contact.
  • DIRECT TRANSFER OF MICROORGANISMS
  • DROPLET SPREAD MAY BE A FORM OF DIRECT CONTACT WHEN THE HOST IS WITHIN 1M/ 3FT
• Any substance serving as a means to transport infectious agents to susceptible hosts.

  Vehicle-borne transmission
• EXAMPLES OF VEHICLE

  1. FOMITES
  2. WATER/FOOD
  3. BLOOD
• WHAT IS THE TRANSMISSION ROUTE OF VEHICLE-BORNE PATHOGENS?

  • INGESTION
  • INHALATION
  • PHYSICAL CONTACT WITH VEHICLE
• WHAT IS THE TRANSMISSION OF PATHOGENS VIA ANIMALS/FLYING/ CRAWLING INSECTS ACTING AS CARRIERS?

  Vector transmission
• WHAT ARE THE VECTOR TYPES?

  • ANIMALS
  • INSECTS
• WHAT ARE THE TRANSMISSION ROUTES OF VECTORS?

  Injection of infectious agents through biting, deposition of feces or other materials on the skin via bite wounds or traumatized skin areas.
• IT IS THE TRANSMISSION OF PATHOGENS THROUGH AIR

  AIRBORNE TRANSMISSION
• WHAT ARE THE TYPES OF TRANSMISSION OF AIRBORNE PATHOGENS?

  • DROPLETS
  • DUST
• WHAT IS THE RESIDUE OF EVAPORATED DROPLETS EMITTED BY INFECTED HOSTS?

  DROPLET NUCLEI
• WHAT IS THE TRANSMISSION ROUTE OF AIRBORNE PATHOGENS?

  Material carried by air currents to a suitable portal of entry, typically the respiratory tract, of another person
• Nonspecific Defenses

  1. Protect against all microorganisms, regardless of prior exposure.
  2. Examples include physical barriers (skin), chemical barriers (stomach acid), and cellular components (macrophages, neutrophils).
• Specific (Immune) Defenses

  1. Directed against identifiable bacteria, viruses, fungi, or other infectious agents.
  2. Utilize immune cells like T cells, B cells, and antibodies tailored to specific pathogens.
• Anatomic and Physiological Barriers

  • First line of defense against microorganisms
  • mucous membranes and cilia
  • Alveolar macrophages
  • Stomach acidity prevents microbial growth
  • Lactobacilli fermentation creates acidic environment
• Intact Skin and Mucous Membranes

  • First line of defense against microorganisms
  • Effective barrier unless broken
  • Skin's dryness deters bacterial penetration
  • Resident bacteria on skin prevent multiplication of other bacteria
• Nasal Passages


  • Moist mucous membranes and cilia trap microorganisms, dust, and foreign materials
• Lungs


  • Alveolar macrophages ingest microorganisms, dead cells, and foreign particles
• Body Orifices

  • Oral cavity sheds mucosal epithelium regularly, saliva contains microbial inhibitors
  • Tears protect the eye, washing away microorganisms and containing lysozyme
  • GI tract: Stomach acidity prevents microbial growth, resident flora in large intestine prevents disease-producing microorganisms
  • Vagina: Lactobacilli fermentation creates acidic environment, inhibiting growth of many microorganisms
  • Urethra entrance harbors microorganisms, urine flow flushes and has bacteriostatic action to prevent ascent
• Inflammatory Response


  Local and nonspecific defensive response of tissues to injurious or infectious agents
• Inflammatory Response


  • Destroys or dilutes injurious agents, prevents further spread of injury, promotes tissue repair
  • Characterized by: Pain, Swelling, Redness, Heat, Impaired function (in severe cases)
• Suffix -itis


  Used to describe inflammatory processes (e.g., appendicitis, gastritis)
• Injurious Agents


  • Physical agents (trauma, heat, cold, radiation)
  • Chemical agents (external irritants, internal irritants)
  • Microorganisms (bacteria, viruses, fungi, parasites)
• Three Stages of Inflammatory Response

  1. Vascular and cellular responses

  2. Exudate production

  3. Reparative phase
• First Stage of Inflammation

  • Blood Vessel Response: Constriction followed by dilation (due to histamine release), Increased blood flow to injured area (hyperemia)
  • Vascular Permeability Increase: Dilation of vessels due to cell death and chemical mediators (bradykinin, serotonin, prostaglandin, histamine), Leakage of fluid, proteins, and leukocytes into interstitial spaces
  • Signs of Inflammation: Swelling (edema) and pain, Pain caused by pressure of accumulating fluid and chemical mediators on nerve endings
  • Impact on Organ Function: Fluid accumulation in body cavities can affect organ function, Impaired mobility in joints
  • Leukocyte Response: Bone marrow produces large numbers of leukocytes (leukocytosis), Normal leukocyte count can rise significantly during inflammation
• Exudate

  Second stage of inflammation, Composition: Fluid from escaped blood vessels, Dead phagocytic cells, Dead tissue cells and their products
• Exudate

  • Components: Fibrinogen (converted to fibrin), Thromboplastin (from injured tissue cells), Platelets
  • Purpose: Form interlacing network to wall off area, prevent spread of injurious agent
  • Clearance: Exudate cleared by lymphatic drainage
  • Types: Serous, Purulent, Hemorrhagic (sanguineous)
• Third Stage of Inflammation: Tissue Repair


  1. Involves regeneration or replacement with fibrous tissue formation (scar)

  2. Regeneration: Replacement of destroyed tissue cells by identical or similar cells, Cells organized to restore tissue architecture and function, Regenerative capacity varies among tissue types

  3. Repair by Fibrous Tissue Formation: When regeneration is not possible, Inflammatory exudate provides framework, Connective tissue elements (collagen, blood capillaries, lymphatics) replace damaged tissue

  4. Granulation Tissue: Early stage of repair process, Fragile, gelatinous tissue, appearing pink or red due to newly formed capillaries

  5. Cicatrix (Scar): Later stage of repair, Tissue shrinks, collagen fibers contract, forming firmer fibrous tissue
• Specific Defenses


  Involve the immune system
• Antigen


  Substance inducing immune responsiveness (immunity)
• Autoantigen


  Antigen originating in one's own body
• Components of Immune Response

  • Antibody-mediated defenses
  • Cell-mediated defenses
• Antibody-Mediated Defenses

  Involves production of antibodies by B cells, Antibodies target and neutralize antigens
• Cell-Mediated Defenses


  Involves actions of T cells, T cells directly attack infected or abnormal cells
• Both antibody-mediated and cell-mediated systems provide distinct but overlapping protection against pathogens
• Antibody-Mediated Defenses (Humoral Immunity)


  Defenses mediated by antibodies produced by B lymphocytes
• B Cells and Antibodies

  • B cells ultimately responsible for producing antibodies, Antibodies (immunoglobulins) are part of the body's plasma proteins