Micro Ch 14

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  1. Contrast normal microbiota and transient microbiota with opportunistic organisms
    transient microbiota: may be present for days/weeks/months then go away 

    Normal microbiota: permanently colonize the host by symbiosis, dont cause disease 

    opportunistic pathogens: dont normally cause disease ( have a symbiotic relationship) until certain conditions. Ex. E coli harmless unless it leaves the large intestine
  2. Compare and contrast commensalism, mutualism, and parasitism
    • commensalism: 1 org benefits, the other is unaffected
    • ex.staphylococcus epidermis

    • mutualism: both organsims benefit 
    • ex. ecoli = vit b and k 

    • parasitism: 1 orgasms benefits at the expense of another 
    • ex. ecoli outside of the small intestine
  3. List kochs postulates 
    describe how kochs postulates can be used to prove the cause of an infectious disease
    To prove the cause of a disease...

    • 1) The same pathogen must be present in every case of the disease
    • 2) The pathogen must be isolated from diseases host and grown in pure culture 
    • 3) The pathogen from the pure culture must cause the disease when its inoculated into a healthy susceptible lab animal
    • 4) The pathogen must be isolated from the inoculated animal and must be shown to be the original animal 

    exceptions: some microbes have unique culture requirements 

    some pathogens can cause several disease conditions, or only in humans 

    • symptom: change in body function felt by a patient as a result of disease
    • sign: change in body that can be measure or observed because of disease
    • syndrome: group of signs/symptoms that go with the disease
  4. Communicable vs noncommunicable
    • communicable: contagious ( spread between hosts) 
    • noncommunicable: not transmitted from 1 host to another 

    • Clostridium perfringens = food poisioning
    • not directly communicable
  5. Categorize disease according to frequency of occurrence
    prevalance: number of people in a pop who develop a disease at a specific time regardless of when it first appeared 

    • epidemic: many hosts short time  
    • pandemic: worldwide epidemic
    • sporadic disease: occurs occasionally in a pop ex. typhoid fever
  6. endemic vs epidemic
    endemic: disease constantly present ex. cold 

    • epidemic: many people in a given area acquire a certain disease in a short period 
    • ex. flu
  7. How does herd immunity develop?

    Categorize diseases according to severity
    immunity in most of a population 

    • acute: symptoms are rapid
    • - primary infection: acute infection causes initial illness
    • -secondary infection: opportunistic infection after a primary ( predisposing) infection

    chronic: disease slowly develops

    latent: disease with no symptoms when the causative agent is inactive
  8. Describe how predisposed factors make the body more susceptible to disease
    • -short urethra in females 
    • -genes ex. sickle cell
    • -climate/weather
    • -fatigue
    • -age
    • -lifestyle
    • -chemo
  9. Proper sequence of the pattern of disease
    • incubation ( no symptoms)
    • prodromal ( mild symptoms)
    • period of illness ( most severe )
    • period of decline( signs and symptoms)
    • period of convalescence
  10. cold incubation period =3 days
    period of disease is usually 5 days

    sitting next to a person with a cold , when will you know whether you contracted it?
    3 days incubation, 4th day mild signs?
  11. Why are carriers and important reservoir of infection?
    • Continual sources of infection
    • ex. humans: aids, gonorrhea 

    carriers: may have inapparent infections or latent diseases 

    • animals: rabies, lyme disease
    • -zoonoses: transmission by direct contact, contaiminated food/water, air by contaminated hides/feathers 

    nonliving: botulism, tetanus ( soil)
  12. How disease is transmitted by contact transmission,vehicle transmission, mechanical transmission, biological transmission
    • Contact:
    • -direct: close association between infected and susceptible host 
    • -indirect: spread by fomites
    • -droplet: airborn droplet transmission

    Vehicle: transmission by an inanimate reservoir ( food, water, air) ex. dirty cutting board 


    • - mechanical: arthropods ex. fleasrs carry pathogens on feet 
    • -biological transmission- pathogens reproduce in vector
  13. Nosocomial infections
    - hospital acquired , affect 5-15% of all hospital patients 

    • -misuse of antibiotics, pesticides 
    • - evolutions of new strains 
    • -microbes in the environment
    • -weakened host 
    • -chain of transmission in a hospital
  14. Spread of emerging infectious diseases
    • - antibiotic misuse
    • -new strains
    • -genetic recombination ( ecoli, avian flu)
    • -change in weather ex. hantaivrus
    • -modern transportation ex. west nile
  15. epidemiology
    epidemiology: study of where and when diseases occure 

    • - case reporting: health workers report specified disease to local, state, national offices 
    • -nationally notifiable diseases: physicans are required to report occurrence
  16. 3 epidemiological investigations

    whats the cdc for
    descriptive: collect and analyze data ex. john snow cholera in london

    analytical: compare of a disease group and healthy ex. florence nightingale and typhus

    experiemental: controlled experiments , ex handwashing decreased puerperal fever 

    CDC: collects and analyzes epidemiological info 

    -publishes morbity and mortality weekly report
  17. morbidity, mortality , notifiable infectious diseases
    morbidity: number of people effected

    mortality: number of people who died 

    notifiable infectious diseases: drs are required to report occurances
  18. In 2003 the morbidity of
    hemolytic uremic syndrome
    morbidity= 176
    mortality = 29
    morbidity was 696

    which disease is more fatal
    29/176 vs 33/696 

    ( 1st one)?

Card Set Information

Micro Ch 14
2016-10-11 04:40:01
Principles of Disease and Epidemiology
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