Epidemiology 1 Flashcards

1
Q

What does epi mean?

A

on the top/on/above

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2
Q

What does demos mean?

A

people / citizens

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3
Q

What does logia mean?

A

knowledge/writing/words/study

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4
Q

What does epidemiology mean?

A

The study of what is upon the people.

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5
Q

Who studied cholera?

A

John Snow

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6
Q

When did john snow study cholera?

A

1846 - 1860

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7
Q

What was cholera originally believed to result from?

A

Believed to result from
“miasma” (odors/gas/vapors from
decomposing animals/humans)

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8
Q

How did John Snow stop spread of cholera in London Soho?

A

Removed pump handles of water pumps so no contaminated water could be drawn from underground.

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9
Q

How does someone get cholera?

A

Drinking or eating food or water contaminated with the bacteria.

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10
Q

what bacteria causes cholera?

A

vibrio cholerae.

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11
Q

Why was the water underground contaminated?

A

Lack of sanitation, inadequate water treatment.

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12
Q

What does cholera do to intestines?

A

Induces loss of fluids in intestine(s)

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13
Q

Is cholera gram neg or gram pos?

A

Gram negative

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14
Q

Why does cholera cause people to lose alot of water?

A

Diarrhoea

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15
Q

What does diarrhoea cause?

A

Dehydration.

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16
Q

At the time of John Snow how was cholera treated?

A

At the time of John Snow, there was no treatments.

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17
Q

How is cholera treated today?

A

Today, we have antibiotics such as doxycycline and water filtration systems. We also have sanitations, hygiene, and vaccination.

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18
Q

What are the three questions asked in epidemiology?

A

1- Location
2- Who
3- When

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19
Q

What happened in Philadelphia 1976?

A

National convention of the american legion.

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20
Q

What do we look at in epidemiology?

A
  • Creating solutions to problems
  • Surveillance
  • Risk factors
  • Interventions and implementation
    This is public health.
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21
Q

What happens in a case control study?

A

A specific group of patients is examined (infected) and is compared
with another group of patients that are called “controls” (non-infected)

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22
Q

What are the case group?

A

Infected

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23
Q

What are the control group?

A

non-infected

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24
Q

What is an Odds Ratio used to do?

A

to assess how likely a patient will develop a disease/condition.

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25
Q

What does it mean if OR > 1 ?

A

patients that have been exposed are more likely to develop the disease/condition

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26
Q

What does it mean if OR = 1 ?

A

no association between exposure and disease/condition

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27
Q

What does it mean if OR < 1 ?

A

patients that have been exposed are more likely to be protected against the disease/condition

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28
Q

Pros of case control studies?

A

Fast
Cost effective (cheap)

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29
Q

Cons of case control studies?

A

Bias
Appropriate controls

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30
Q

What is a cohort study?

A

A cohort (group of patients) is followed over time.
Initially, patients are healthy

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31
Q

What is the aim of a cohort study?

A

Aim = determine factors causing a disease/condition

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32
Q

What is a Relative risk used to do?

A

This is a way to assess the probability to develop a disease/condition

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33
Q

What is RR?

A

relative risk

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34
Q

What is OR?

A

Odds ratio.

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35
Q

Whats it mean if RR > 1 ?

A

patients that have been exposed are more likely to develop the disease/condition

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36
Q

Whats it mean if RR = 1 ?

A

no association between exposure and disease/condition

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37
Q

Whats it mean if RR < 1 ?

A

patients that have been exposed are more likely to be protected against the disease/condition

38
Q

Pros of cohort studies?

A

True estimations
Patients are followed longitudinally

39
Q

Cons of cohort study?

A

Slow
Expensive

40
Q

What does a descriptive study involve?

A

1- Case report
Focusing on a single patient (n=1)
eg: a rare disease observed in a patient

2- Case series
Focusing on a few patient
eg: a condition observed in several patients (n~30)

41
Q

How are health problems solved?

A

Step 1 = Data collection
Step 2 = Assessment
Step 3 = Hypothesis testing
Step 4 = Action

Afterwards,

Step 1 = Surveillance
Step 2 = Inference
Step 3 = Determine how and why
Step 4 = Intervention

42
Q

What does it mean if there is no agent?

A

No agent = genetics?
Eg – dementia, MS, autoimmune diseases.

43
Q

What can epidemiology be performed on?

A

Epidemiology can be performed on communicable or non-communicable disease(s)

44
Q

Define epidemic?

A

An epidemic is the consequences of an outbreak of diseases, usually caused by agents
exception : obesity (for example)

45
Q

What does an outbreak involve?

A

An outbreak involves a cluster

46
Q

Why can tractors kill people in georgia usa?

A

Lack of experience
Lack of awarness
Lack of strength
Hills causing tractors to roll back and run people over, especially in the north.

47
Q

What is incidence proportion also known as?

A

also called “cumulative incidence

48
Q

What is Incidence rate also known as?

A

also called “incidence density rate”
and “person-time incidence rate”

49
Q

Why more adults obese than kids?

A

Metabolism slows - harder to keep at a healthy weight.
Unhealthy eating habits
Less exercise / sedentary life style.

50
Q

Why might more boys be obese than girls?

A

Girls may have healthier diets. (eg, girls = veg, boys = fried food)
Men eat more since men have bigger bodies on average.
Maybe girls exercise more than men do.

51
Q

What is the course of action to avoid an epidemic?

A

1- Continuous monitoring
2- Early detection
3- Efficient containment
4- Prevention

52
Q

What does continuous monitoring consist of?

A
  • Registry of infectious diseases
    —HIV, ZEBV, TB
  • Trend analysis
    —constant, exponential, sigmoid, logarithmic
53
Q

What does early detection consist of?

A
  • Diagnostic, tests, laboratories
    —PCR, ELISA
54
Q

What does efficient containment consist of?

A
  • Isolation, lockdown
  • Treatment
    —Antibiotics (bacteria)
55
Q

What does prevention consist of?

A
  • Vaccination, education, public policies
  • Research
    —Clinical trials
56
Q

What are ALSO attack rates?

A

% ill

57
Q

Why are older people more prone to illness and more likely become infected and ill?

A

Weaker immune systems

58
Q

What cause of action do you take after examining/observing a disease?

A

Hypothesis

59
Q

What would a hypothesis of a disease include?

A

Why?
Disease caused by what/who ?
Is the disease transmissible?

60
Q

How was legionnaires’ disease HYPOTHESISED to be transmitted?

A

“Investigation of the mode of transmission included the following general categories:
person to person,
food,
tobacco,
alcohol,
water,
animals,
ice,
fomites,
and air.”

61
Q

What are fomites?

A

Furniture / non living surfaces.

62
Q

What did the authors of the hypothesis conclude to be the modes of transmission of legionnairres disease?

A

Tobacco
Water
Air

Therefore:
non-communicable,
lung function,
air-borne,
in water.

63
Q

How was spread of legionnaires disease made worse by the hotels?

A

Spread by cooling tower of the hotel’s air conditioning system

64
Q

Conclusions of acquisition of legionnaires disease?

A
  • May be residentially acquired
  • Associated with domestic potable water and disruptions in residential plumbing systems

Potential strategies to reduce legionnaires risk:
- Consistent chlorination of potable water
- Increasing water heater temperatures
- Limiting exposure to aerosols after domestic plumbing repairs.

65
Q

How is legionella controlled?

A

1) Chlorine
2) Heat

66
Q

Is there a vaccine for legionella?

A

No vaccine (yet?)

67
Q

What type of microbe is legionella?

A

Bacteria

68
Q

What microbe causes legionnaires disease?

A

Legionella pneumophila

69
Q

What was the bacterium named after?

A

named after the legionnaires.

70
Q

What unusual infections did patients display in 1980 - May 1981?

A

Patients presented unusual infections
Candida albicans
Kaposi sarcoma
CMV
Pneumocystis carinii

71
Q

What unusual symptoms did patients display in 1980 - May 1981?

A

Patients (young) presented unusual symptoms
fever
liver dysfunction
leukopenia
Hodgkins disease
cough, dyspnea

72
Q

What did all the patients in 1980 - May 1981 have in common?

A

All were homosexuals

73
Q

What is the pathway of origin of HIV?

A
  • Came from red-capped mangabeys and greater spot-nosed monkeys (SIVrcm or SIVgsn or other).
  • Then adaptation to chimpanzees (SIVcpz (+Vif))(perhaps another animal had it before chimpanzees but this is unknown/unconfirmed. Perhaps this species went extinct)
  • Then adaptation to humans (HIV-1)
74
Q

What are the three major types of HIV?

A

N, M, and O.

Each derived from a separate transfer event.

75
Q

What is the probable transmission of HIV between monkeys?

A

Bush meats

76
Q

Examples of bush meats?

A

Bats
Pangolins
Rats

77
Q

How might have we gotten HIV from the animals?

A

Probable transmission -> adaptation/mutations

  1. interactions with animals
  2. transportation
  3. urbanization
78
Q

What is the technique used in phylogenic trees when determining the origin of a disease?

A

Sequence comparisons

79
Q

Where have collections of plasma of HIV been found?

A

Collection of 1,213 plasma
from Léopoldville, DRC, 1959
-> identification of HIV-1
(“ZR59”)

Collection of 27 tissues
from Kinshasa, Kenya, 1960
-> identification of HIV-1
(“DRC60”)

80
Q

When was the probable entry into humans of HIV?

A

1884-1924

81
Q

How does legionnaires and HIV spread so fast in developing countries?

A
  • Settlements
    -increased population
    -promiscuity
    -Sex workers
82
Q

What are the two partner sutdies

A

PARTNER-1 : heterosexuals + gay men
PARTNER-2 : gay men

83
Q

What type of study are the partner studies?

A

Observational studies

84
Q

WHat happened in partner-1 study?

A

MSM couples reported approx 22,000 condomless sex acts and heterosexuals approx 36,000. There were no phylogenetically
linked transmissions occurred over eligible couple years of follow-up, giving a rate of within-couple HIV transmission of zero. All HIV positive partners were using Suppressive Antiretroviral Therapy.

85
Q

What did partner-2 study show?

A

Couples reported condomless anal sex a total of 76 088 times. Infections occurred during eligible couple years of follow-up, but none were phylogenetically linked within-couple transmissions, resulting in an HIV transmission
rate of zero. All HIV positive partners were using Suppressive Antiretroviral Therapy.

86
Q

What do the partner studies show?

A

Shows how effective the treatments such as ART are and their important role in prevention of HIV.

87
Q

What is ART?

A

antiretroviral therapy.

88
Q

How can we reduce HIV transmission?

A
  1. Access to condoms
  2. Access to ART (treatment)
  3. Public policies (prevention)
  4. Education (prevention)
  5. More research -> cure ? vaccine?
89
Q

Whats the equation for relative risk (RR)?

A

RR = (A/(A+B)) / (C/(C+D))

90
Q

Whats the equation for OR?

A

OR = (A/C) / (B/D)

Alternatively:

OR = (AD) / (BC)