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2012-11-27 10:25:01

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  1. etiology, pathogenesis, infection, infectious disease
    • etiology: study of cause of disease
    • pathogenesis: development of disease
    • infection: colonization of body by pathogen
    • infectious disease: can be transmitted from one individual to another
  2. communicable disease, noncommunicable dissease, contagious disease
    • communicable disease: can spread from one host to another
    • noncommunicable dissease: not transmitted from one host to another
    • contagious disease: easily spread from one host to another
  3. signs, symptoms, syndrome
    • signs: change in body that can be measure or observed (fever, rash)
    • symptoms: change in body function felt by the host
    • syndrome: specific group of signs and symptoms that accompany a disease
  4. sporadic disease, endemic disease, epidemic disease, pandemic disease
    • sporadic disease: occurs only occasionally in a population (Typhoid fever)
    • endemic disease: constantly present in a population (common cold)
    • epidemic disease: acquired by many hosts in a given area in a short time (influenza)
    • pandemic disease: worldwide epidemic (AIDS)
  5. acute disease, chronic disease, subacute disease, latent disease
    • acute disease: develop rapidly and lasts only a short time (influenza)
    • chronic disease: develops slowly, less severe but lasts for a long time (TB, hep B) - typically more fatal
    • subacute disease: intermediate between acute and chronic (sclerosing panencephalitis)
    • latent disease: period of no symptoms when the pathogen is inactive (shingles
  6. local infection, systemic infection, focal infection
    • local infection: limited to a very small area of the body (boils, abscesses)
    • systemic infection: infection throughout body (measles)
    • focal infection: systemic infection that began as local infection (gets into blood stream)
  7. bacterermia, septicemia, toxemia, viremia
    • bacterermia: bacteria in blood stream
    • septicemia: multiplication of pathogens in the blood stream
    • toxemia: toxins in blood
    • viremia: viruses in blood
  8. primary infection, secondary infection, subclinical infection
    • primary infection: actue infection that causes initial illness
    • secondary infection: opportunistic infection after a primary (predisposing) infection; more serious
    • subclinical infection: no noticeable signs or symptoms (inapparent infection)
  9. Period of incubation, prodromal period, period of illness, period of decline, period of convalescence
    • Incubation period: (no signs or symptoms) Time from which you are infected to when symptoms begin
    • Prodromal period: (mild signs or symptoms) Begin to show signs/symptoms
    • Period of illness: (most severe signs/symptoms) Sick, immune system kicks in
    • Period of decline: (signs and symptoms) Occurs if body overcomes pathogen
    • Period of convalescence: body returns to normal (days to weeks)
  10. Define/explain microbial antagonism
    • Normal microbiota compete with pathogens to prevent overgrowth/infection
    • Compete for nutrients, space (competitive exclusion - C. difficile completely line the GI tract so pathogens literally cannot attach)
    • Produce substances harmful to invader (acids or bacteriocins)
  11. Describe symbiosis and the types
    • Symbiosis: living together of two different organisms
    • Commensalism: one organism benefits with the other is unaffected (Staphylococcus epidermidis on the skin)
    • Mutualism: both organisms benefit (E. coli bacteria in the large intestine)
    • Parasitism: one organism benefits while the other is harmed (H1N1 virus)
  12. Differentiate between normal flora and transient microbiota
    • Normal microbiota
    • Reside permanently in/on body [FOR LIFE]
    • Normally do NOT produce disease
    • Are aquired young (lactobacilli from vag, breathing, breast feeding, etc)
    • Transient microbiota
    • Present for a while then disappear [DAYS to YEARS]
    • Normally do not produce disease (unless they go where they "aren't supposed to")
    • Acquired from being kissed, touched, etc
  13. What is an opportunistic pathogen?
    Normal microbiota do not causes disease in their normal habitat, but do so when in a different environment (Streptococcus epidermidis on skin is no big, but in cuts = you're fucked)
  14. List the locations of normal flora
    • Nose
    • throate
    • lungs
    • any air-exposed part of body
    • eye
    • mouth
    • skin
    • large intestine (MANY)
    • small intestine (few)
    • urinary tract
    • reproductive system
  15. Discuss the benefits and possible dangers of normal flora including microbial antagonism/synergism
    • Benefits
    • Protects host by microbial antagonism (competitive exclusion)
    • Synthesize B vitamins and K vitamins for host (we can't)
    • Stimulate immune response (keeps it "sharp")
    • Dangers
    • Opportunism (cause disease in different habitat)
    • Microbial synergism (two microbes act together to produce a greater effect eg. Streptococci and periodontal pathogens)
  16. Describe predisposing factors for disease
    • Short urethra in females
    • Inherited trades (sickle cell gene)
    • Climate and weather (common cold)
    • fatigue (stress)
    • age (very young and very old are most susceptable)
    • lifestyle
    • chemotherapy
    • antibiotic therapy
  17. Explain three general methods of disease transmission and give one example of each
    • Direct: requires close association or physical contact
    • Indirect: spread by means of fomites
    • Droplets: discharged from sneezing, coughing, etc
    • VEHICLE - Transmission by inanimate reservoir
    • Waterborne: sewage contaminated water
    • Foodborned: incompletely cooked, poor storage, unsanitary conditions
    • Airborne: droplets, dust, dirt
    • VECTORS - Arthropods carry pathogens from one host to another
    • Mechanical transmission: houseflies (typhoid fever, bacillary dysentery)
    • Biological transmission: mosquitoes (malaria)
  18. List several methods of disease transmission in hospitals and explain how nosocomial infections can be prevented
    • Direct contact: patient to patient, staff ot patient, visitors to patient
    • Indirect contact: fomites, hospital venitalation system
    • Nosocomial infections can be prevented by use of aseptic techniques, education about infection control, hand washing, and use of isolation rooms/wards
  19. List several approaches that will break the chain of transmission in an epidemic
    • Remove reservoirs
    • Water purification
    • Vector control (insect, rodent, arthropod)
    • Isolation
    • Treat carriers
    • Safe sex
    • Proper food handling
    • Hand washing (#1)
  20. List and describ Koch's postulates, their significance/applicibilty
    • Koch's postulates demonstrate that a specific pathogen cause a specific disease
    • 1. Microorganisms are isolated from a diseased or dead animal
    • 2a. The microorganisms are grown in pure culture
    • 2b. The microorganisms are identified
    • 3. The microorganisms are injected into a healthy laboratory animal
    • 4. Disease is reprooduced in a laboratory animal
    • 5a. The microorganisms are isolated from this animal and grown in pure culture
    • 5b. Microorganisms are identified (must be same as 2b)
  21. Describe the limitations to Koch's postulates
    • Some causative agents cannot be cultured on existing articifical media (viruses, Micobacteria lepriae)
    • Some diseases are not clear-cut (various pathogens causing similar signs and symptoms)
    • Some pathogens may cause several disease conditions
    • Infecting humans with infections agents is unethical, may not be pathogenic in other organisms
  22. Define reservoir. List/describe the types of reservoirs and portals of exit
    • Reservoir of infection: continual source of pathogens
    • Living
    • Human: harbor and transmit pathogens to others; carriers (AIDS, gonorrhea)
    • Animal: carry pathogens that causes disease in humans (rabies, lyme disease)
    • *Zoonoses - animal diseases that may be transmistted to humans
    • Soil: fungal (mycoses); bacterial (botulism, tetanus)
    • Water: cause gastrointestinal infections (cholera, amoebic dysentary)
    • Food: inadequately cooked, improperly prepared, or stored (Tricinella, food poisoning)
  23. List the 3 major determinantos of nosocomial infections
    • Susceptibility of host (broken skin, compromised immune system)
    • Microorganisms in hospital environment (reservoirs for pathogens, patients/staff/visitors, hospital microbes tend to be more resistant to drugs)
    • Chain of transmission (direct contact between patients and staff, fomites)
  24. List and describe the sources of microorganisms involved in nosocomial infections
    • Endogenous: patients themselves (touching a cut)
    • Exogenous: staff, visitors, or other patients
  25. List and describe the common bacterial causes of nosocomial infections
    • Urinary tract infections
    • Surgical site infections
    • Lower respiratory tract infections
    • Bacteremia transmitted primarily by IV catheterizations
    • Cutaneous infections
    • Other
  26. Define epidemotiology, descriptive epidemiology, analytical epdimediology, experimental epidemiology
    • epidemiology: Study of where and when diseases occur
    • descriptive epidemiology: collection and analysis of data (mapped occurrence of cholera to a specific well in London)
    • analytical epdimediology: comparison of a diseased group and a healthy group (improved sanitation decreased incidence of epidemic typhus)
    • experimental epidemiology: controlled experiments (handwashing decreased incidence of puerperal fever)