Microbio Q3

  1. Pathogen
    • any disease causing microorganism
    • 2 types: True/Primary pathogen & opportunistic pathogen
  2. true/primary pathogen
    • can cause infection and disease in healthy people
    • aka frank pathogen
  3. opportunistic pathogen
    can infect host only when immune defense is weakened
  4. parasite
    • pathogen is a parasite
    • any organism that lives on or in another organism and is either metabolically dependent upon that organisms or derives nutrients from that organism
    • have complex microbial interaction where one organism benefits from the association and the other organism is usually harmed or killed
  5. host
    a larger organism that supports the survival and growth of a smaller organism.
  6. parasitism
    • often requires an extended relationship or coexistence between parasite and host .
    • Is an example of symbiosis (the living together of organisms).
  7. parasite life cycle
    • Parasites have complex life cycles
    • Parasitic infections usually involve several hosts:
    • Definitive host
    • Intermediate host(s)
  8. definitive (final) host
    • Maintains the mature form of the parasite
    • Also, maintains the sexually reproductive form of the parasite
  9. Intermediate host
    • Maintains the immature parasites
    • The immature parasite usually undergoes various stages of maturation before being transferred to the definitive host
  10. Pathogenicity
    the ability of microbes to cause disease; the capacity of a pathogen to invade and harm a host
  11. Pathogenesis
    the steps involved in disease progression within the host
  12. Virulence
    • the degree or intensity of pathogenicity
    • -Is an important indicator of disease progression after infection by a pathogen
    • -Is determined by factors associated with the pathogen (called virulence factors)
  13. Virulence Factor
    • A product of microbes that increases the invasiveness or pathogenicity of the organism
    • contribute to tissue damage
    • can be integral microbial cell components or secreted products e.g. LPS, capsule, fimbriae
    • Can be secreted products; e.g. enzymes, toxins
    • Can be genetic; e.g. presence of resistance genes
  14. pathogenicity islands
    large segments of DNA that code for virulence factors; often acquired during horizontal transfer
  15. infectivity
    the ability of microorganisms to establish an infection
  16. Infectious dose (ID50)
    the number of pathogens that infect 50% of hosts within a specified period of time
  17. Invasiveness
    the ability of microorganisms to spread to adjacent tissues or other anatomical areas
  18. Lethal dose (LD50)
    the number of pathogens that kill 50% of hosts within a specified period of time; often associated with toxin production
  19. Indications of morbidity (signs)
    • -signs
    • -redness, runny nose, swelling, rash, coughing, pus formation, fever, vomiting, diarrhea
  20. Signs
    objective evidence of disease-characteristics of a disease that can be observed by someone else in addition to the patient
  21. Symptoms
    • -subjective evidence of disease
    • -characteristics of disease that can only be determined [experienced] by the patient
  22. Indications of morbidity (symptoms)
    • Pain
    • Shortness of breath
    • Nausea
    • Sore throat
    • Headache
    • Malaise (discomfort)
  23. Inflammation
    • a nonspecific defense mechanism by the body in response to infection, injury or chemical irritation
    • Characterized by:
    • Rubor: redness-from blood accumulation
    • Calor: heat-Warmth generated from the blood due to vasoconstriction
    • Tumor: swelling (edema)-from the accumulation of fluid in surrounding tissue
    • Dolor: pain-Soreness or tenderness from injury to local nerves
    • Sometimes itching (pruritus)
Card Set
Microbio Q3