quiz 2 ai

• Disease ensues when the cumulative effects of infection on tissue/organ disruption
• Host


  Any organism that harbors another organism
• Virulence Factors

  1. Animal passage

  2. Attenuation

  3. Transposal of virulence
• Infection


  Pathogenic microorganisms penetrate host defenses, enter the tissues, and multiply
• Symbiosis

  • Mutualism
  • Commensalism
  • Parasitism
• Pathogenicity


  Refers to the ability to cause a disease
• Factors Affecting Pathogenicity

  1. Invasiveness/Infectiveness

  2. Dose

  3. Viability

  4. Toxigenicity

  5. Specificity
• Disease


  Occurs when an infection results in any change from a state of health, abnormal state in which part or all of the body is not properly adjusted or incapable of performing its normal functions
• Classification of Disease

  • Inherited Disease
  • Congenital Disease
  • Degenerative Disease
  • Nutritional deficiency disease
  • Endocrine diseases
  • Mental disease
• Symbiosis


  Association between two or more species (living together)
• Contamination refers to the presence of microorganisms
• Infestation refers to the presence of larger parasites in the body such as worms and arthropods
• Normal flora (microflora)

  • Resident microflora
  • Transient microflora
  • Opportunist
• Pathology


  Study of disease, concerned with etiology (cause), pathogenesis (manner in which a disease develops), and the structural and functional changes brought about by the disease
• Factors Affecting Pathogenicity

  1. Mode of action

  2. Virulence
• Kinds of Disease

  • Infectious Disease
  • Non-infectious Disease
• Infection

  Invasion/colonization of the body by pathogenic microorganisms, may exist in the absence of detectable disease
• Iatrogenic disease


  • Caused by medical procedures or treatment, e.g., Surgical error, drug reaction, and infections acquired from hospital treatment
• Endocrine diseases


  • Due to excessive or deficiency in hormones, e.g., Viral infection linked to pancreatic damage that leads to IDDM
• Quantity of microbes in the inoculating dose
• LOW INFECTIOUS DOSE, HIGH VIRULENCE
• Immunological disease


  • Allergies, autoimmune disease, and immunodeficiencies caused by malfunction of the immune system, e.g., AIDS
• Pathogen Communicability

  • An infectious disease is caused by a microorganism but is not necessarily communicable
  • A Communicable Disease can be passed from person to person
  • A Contagious Disease can be described as a communicable disease that is easily passed from person to person (i.e., highly communicable)
  • An individual who is asymptomatic but still contagious is described as a carrier
• Course of Infectious Disease

  • Incubation period is the interval between exposure and illness onset
  • Convalescence is a time of recuperation and recovery from illness
  • PRODROMAL and INVASIVE PHASE
  • ACME
  • DECLINE
  • CONVALESCENT
  • FULMINANT - severe and sudden in onset
  • Variation in Incubation Periods
• Bacteremia does not necessarily imply disease. Contrast with "Localized."
• EXTENT OF HOST INVOLVEMENT

  • Primary - Infection in a previously healthy person
  • Secondary - Infection that follows a primary infection
  • Mixed - Infection caused by two or more pathogens
  • Inapparent - Infection that fails to produce a full set of signs and symptoms
• Warning Signals of Disease

  • Signs
  • Symptoms
  • Fever
  • Chills
  • Septicemia
  • Pain, irritation
  • Microbes in the fluids
  • Nausea
  • Chest sounds (wheezes, crackles)
  • Malaise, fatigue
  • Skin lesions
  • Chest tightness
  • Leukocytosis
  • Itching
  • Leukopenia
  • Headache
  • Lymphadenopathy
  • Abdominal discomfort
  • Tachycardia
  • Anorexia
  • Presence of antibodies in serum
  • Sore throat
• Neoplastic diseases


  • Abnormal cell growth that leads to the formation of various types of generally harmless or cancerous growths or tumors, e.g., Papilloma virus
• Idiopathic disease


  • Diseases whose cause is unknown
• INFECTIOUS DOSE: Minimum number of microbes required to initiate an infection
• Mental disease


  • Caused by emotional or psychogenic in nature or certain infections
• INFECTION: SIZE OF INOCULUM
• Deficiency disease


  • Lower resistance to infectious disease and contribute to the severity of infections, e.g., Corynebacterium diphtheriae
• INFECTIOUS DOSE: Gonorrhea - 1,000 cells, Typhoid Fever - 10,000 cells, Cholera - 1,000,000,000
• Systemic Infection

  • Symptom = indications of disease that cannot be objectively measured, e.g., "It hurts!"
  • Sign = indications of disease that can be objectively measured, e.g., body temperature
  • Syndrome = a collection of signs and symptoms that typically are associated with a given cause
  • Subclinical or Inapparent Infection = symptoms are sufficiently mild that they go unnoticed
• OCCURRENCE OF DISEASE

  • SPORADIC - Particular disease occurs only OCCASIONALLY
  • ENDEMIC - Disease constantly pre
• EXTENT OF HOST INVOLVEMENT

  • Localized - Confined to specific tissue
  • Systemic - Infection spread to several sites, usually in the bloodstream
  • Focal - Exists when the infectious agent breaks loose from a local infection and is carried to other tissues
• Course of Infectious Disease

  • SEVERITY / DURATION OF DISEASE
  • ACUTE - One that develops rapidly only a short time
  • CHRONIC - Develops more slowly and the body's reactions may be less severe, but this disease is likely to be continual or recurrent
  • SUBACUTE - Intermediate between acute and chronic
  • LATENT - Causative agent remains inactive for a time but becomes active to produce symptoms of disease
• Infection: Chain of Infection

  • Infectious Agent
  • Reservoir
  • Portal of Exit
  • Mode of Transmission
  • Portal of Entry
  • Susceptible Host
• Effecting Disease

  To cause disease, microbes do most of the following: Gain access to the host (contamination), Adhere to the host (adherence), Replicate on the host (colonization), Invade tissues (invasion), And produce toxins or other agents that cause host harm (damage)