Lecture 14: principles of disease and epidemiology Flashcards

1
Q

What is a pathogen?

A

disease causing microorganism

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2
Q

What is Pathology?

A

the study of disease

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3
Q

Define etiology

A

the study of the CAUSES of disease

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4
Q

What is pathogensis?

A

the process of the development of disease

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5
Q

What is an infection?

A

pathogens invade/colonize the body

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6
Q

What is a disease?

A

abnormal state of the body in which it is not performing normally - Functionally & Structurally

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7
Q

When does the human microbiom develop? How many cells?

A

in utero- before birth
~ 40 trill bacterial cells

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8
Q

What is the human microbiome project (2007)?

A

analyzes relationships between microbial communities on the body and human health

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9
Q

What are normal microbiota?

A

permanently colonize the host & do not cause disease under normal conditions

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10
Q

What are transient microbiota?

A

may be present for days, weeks, or months

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11
Q

The distrubution and composition of normal microbiota are determined by what factors?

A

nutrients
physical & chem factors
host defenses
- immune system
mechanical factors
- chewing

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12
Q

What is microbial antagonism (competitive exclusion)?

A

competition between normal & harmful microbes for food, energy, etc.

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13
Q

What is symbiosis?

A

relationship between normal microbiota and the host

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14
Q

What is commensalism, mutualism, and parasitism?

A

commensalism: one organism benefits, and the other is unaffected
mutualism: both organism benefit
parasitism: one organism benefits at the expense of the other

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15
Q

What are opportunistic pathogens?

A

may cause disease in immunocompromised or unhealthy people
- take the opportunity to attack its host since immune system is not as strong to fight back

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16
Q

Who was Koch, and what did he do?

A

german physicist & microbiologist
- discovered some disease causing bacteria
- incl: anthrax, cholera

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17
Q

What does Koch’s Postulates state?

A
  1. same pathogen must be present in every case of one disease
  2. pathogen must be isolated from disease host & grown in pure culture
  3. pathogen from. pure culture must cause disease when inoculated into a healthy lab animal
  4. pathogen must be isolated from the inoculated animal and must be shown to be the orig organism
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18
Q

What is Koch’s postulates used for?

A

prove whether a microorganism is the cause of an infectious disease

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19
Q

What are some exceptions to Kochs postulates?

A
  • some pathogens can cause several disease conditions
  • some pathogens cause disease only in humans
  • some microbes have never been cultured
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20
Q

How can we classify infectious diseases?

A

symptoms: changes in bodily function felt by patient as a result of disease
signs: changes in body that can be measured or observed as a result of disease
syndrome: specific group of signs & symptoms that accompany a disease

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21
Q

What is a communicable disease?

A

disease that is spread from one host to another

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22
Q

What is a contagious disease?

A

disease that are easily & rapidly spread from one host to another

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23
Q

What is noncommunicable disease?

A

disease that is not spread from one host to another
ex: diabetes, cancer

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24
Q

What is an incidence & a risk, relating to disease?

A

of people who develop a disease during a particular time period
risk= measures rate of new onsets of disease

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25
Q

What is prevalence?

A

of people who developed a disease at a point in time, regardless of when it first appeared

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26
Q

What is a sporadic disease?

A

occurs only occasionally

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27
Q

What is an endemic disease

A

constantly present in a population

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28
Q

what is an epidemic disease?

A

occurence of a disease or health related event clearly in excess of a normal expectation

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29
Q

What is a pandemic disease?

A

epidemic that spreads across regions

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30
Q

What is acute disease?

A

symptoms develop rapidly but the disease lasts only a short time

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31
Q

What is a chronic disease?

A

symptoms develop slowly & last a long period of time/indefinitely

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32
Q

What is a subacute disease?

A

intermediate between acute and chronic

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33
Q

What is a latent disease?

A

causative agent is inactive for a time but then activates and produces symptoms

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34
Q

What is a herd immunity?

A

immunity in most of a population

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35
Q

What is a local infection?

A

pathogens are limited to a small area of the body

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36
Q

What is systemic (generalized) infection?

A

an infection throughout the body

37
Q

What is a focal infection?

A

systemic infection that began as a local infection

38
Q

What is sepsis?

A

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infeciton

39
Q

What is bacteremia?

A

bacteria in the blood

40
Q

What is septicemia?

A

growth of bacteria in the blood

41
Q

What is toxemia?

A

toxins in the blood

42
Q

What is viremia?

A

viruses in the blood

43
Q

What is primary infection?

A

acute infection that causes the initial illness

44
Q

What is secondary infection?

A

opportunistic infection after a primary (predisposing) infection

45
Q

What is a subclinical disease?

A

no noticeable signs or symptoms (inapparent infection)

46
Q

What are predisposing factors?

A

genders
inherited traits
climate & weather
lack of vaccination
fatigue
age
lifestyle
nutrition
chemotherapy

47
Q

What are the periods of the development disease?

A

incubation period: interval between initial infection & first signs and symptoms
prodromal period: short period after incubation; early, mild symptoms
period of illness: disease is most severe
period of decline: signs and symptoms subside
period of convalescene: body returns to its prediseased state

48
Q

What are reservoirs of infection?

A

provides a pathogen with adequate conditions to survive, multiply, and transmit

49
Q

What is a human reservoir?

A

Diseases that are transmitted from person to person without intermediaries

carriers may have inapparent infections or latent disease

50
Q

What are animal reservoirs?

A

diseases that are transmitted from animal to animal
- zoonoses are diseases transmitted from animals to humans

51
Q

What are nonliving reservoirs?

A

soil and water

52
Q

What is direct contact transmission

A

requires close association between the infected and a susceptible host
- monkey pox

53
Q

What is congenital transmission

A

transmission from mother to fetus or newborn at birth
- congenital syphilis

54
Q

What is indirect contact transmission

A

spreads to a host by a nonliving object called a fomite

fomite - objects or materials which are likely to carry infection, such as clothes, utensils, and furniture.
- salmonella

55
Q

What is droplet transmission

A

transmission via airborne droplets less than 1 meter
- covid-19

56
Q

What is vehicle transmission? Give examples

A

transmission by an inanimate reservoir
- airborne
tuberculosis
- waterborne
leptospirosis
- foodborne
salmonella

57
Q

What are vectors? give examples

A

infections transmitted by the bite of infected arthropod species
- arthropods: fleas, ticks, mosquitos

58
Q

What are the two different ways vectors transmit diseases?

A
  1. mechanical transmission; arthropod carries pathogen on its feet - flies & shigella
  2. biological transmission: pathogen reproduces in the vector; transmitted via bites/feces - mosquitos & malaria
59
Q

What are healthcare-associated infections?

A

acquired while receiving treatment in a health care facility
- nosocomial infections

affect 1 in 25 hospital patients
- 2 mill per year infected, over 70,000 deaths
- 3% preventable

60
Q

What do HAIs (healthcare-associated infections)

A
  • microorganisms in the hospital environment
  • weakened status of the host
  • chain of transmission in a hospital
61
Q

What are universal precautions?

A

safety precautions used with every client

62
Q

What are standard precautions?

A

basic, minimum practices
- ppe, hand and respiratory hygiene

63
Q

What are transmission based precautions?

A

supplemental to standard precautions; designed for known or suspected infections
- contact precautions
- droplet precautions
- airborne precautions

64
Q

What are ways we can reduce number of pathogens?

A

handwashing
- health care workers only wash their hands before handling patients 40% of the time
- disinfecting tubs used to bath
limiting antibiotics

65
Q

What are emerging infectious diseases?

A

new diseases, increasing in incidence, showing a potential to increase in the near future
- most are zoonotic, of viral origin, likely to be vector-borne 75%

66
Q

What are the criteria of emerging infectious diseases?

A
  • distinctly different symptoms
  • local disease -> widespread
  • rare disease -> commom
  • mild -> severe
  • increase in lifespan
  • public health failure
  • bioterrorism
67
Q

What are the 4 steps to address EIDs?

A
  1. detect, investigate, & monitor pathogen, disease, factors of influence
  2. expand research on host interactions, environmental factors, and microbial adaptations
  3. enhance communication and implementation of prevention strategies
  4. establish plans to monitor and control EIDs worldwide
68
Q

define epidemiology

A

study of the distribution and determinants of health-related events in human populations

69
Q

What is an epidemiologists? What do they do?

A

determine causes and origin of disease
- identify important factors concerning the spread of disease
- help develop methods for controlling a disease
- comparisons
- assemble data and graphs

70
Q

What are the basic tenent(s) of epidemiology?

A

disease is not randomly distributed in popul;ations
different pop. subgroups may experience disease occurrence differently
- exploring why
- clues to disease causation or prevention may be found

71
Q

Who is the father of epidemiology?

A

John Snow
- contact contamination
- sanitation
- broad st.pump handle
- Koch

72
Q

Who is “the lady with the lamp”

A
  • Florence Nightingale
  • founder of modern nursing
  • nurse and statistician
  • 1000-page statistical report
    > soldiers
    > disease, food, unsanitary conditions
73
Q

What is descriptive epidemiology?

A

the study of the distribution of health-related events by:
- collecting all data that describe the occurence of a disease under study
- helps generate hypothesis

JOHN SNOW

74
Q

What kind of data is collected in descriptive epidemiology?

A
  • person (who)
    > age, sex, ethnicity, SES, occupation, behavioral practices
  • Time (when)
    > seasonal, incubation period
  • Place (where)
    > urban vs rural, variation by geographic location, clustering
75
Q

What is analytical epidemiology?

A

study of determinants of causes of disease
- analyzes a particular disease to understand its cause
- comparison group
- helps test hypothesis
FLORENCE NIGHTINGALE

76
Q

What is experimental epidemiology?

A

involves a hypothesis and controlled experiments
- clinical trial: test & control group
- community intervention trials

77
Q

What does the CDC do?

A

collects and analyzes epidemiological information in the US
- publishes Morbidity and Mortality Weekly Report (MMWR)
> morbidity; incidence of specific notifiable diseases
> mortality; deaths from these notifiable disease

78
Q

What are notifiable infectious diseases? Morbidity rate? Mortality rate?

A

NID: diseases in which physicians are required to report occurrence
morbidity rate: # of new cases of disease over a specific time in relation to total population
mortality rate: # of new cases of deaths from a disease over a specific time in relation to total population

79
Q

What is an example of a foodborne pathogen?

A

salmonella, norovirus, HEP A

80
Q

Indirect transmission can be spread by a non-living object known as __________.

A

fomite

81
Q

Give an example of contact transmission, vehicle transmission, mechanical transmission, & biological transmission

A
  • stis
  • waterborne, foodborne, or airborne
  • flies
  • mosquitos
82
Q

What is the difference between biological and mechanical vector?

A

mechanical spreads via feet
biological spreads via replication inside vector host

83
Q

What interacting factors result in nosocomial infections

A

microorganisms in hospital
weakened state of host
chain of transmission

84
Q

What is a compromised host?

A

a host whose ability to fight infection is weakened

85
Q

How can nosocomial infections be prevented?

A

hand washing, respiratory hygiene, PPE, disinfecting

86
Q

After learning that 40 hospital employees developed nausea & vomiting, the hospital infection control officer determined that 39 ill people ate green beans in the hospital cafeteria, compared to 34 healthy people who ate in the cafeteria the same day but did not eat green beans in the hospital cafeteria. What type of epidemiology is this?

A

analytical

87
Q

What kind of observational study was florence nightingales study with the military?

A

case-control study

88
Q

Morbidity vs Mortality

A
  • # of persons disease
  • # of deaths