L7: Epidemiology Flashcards

1
Q

The epidemiologic triad is a pattern of interaction between: ____, _____, and ____

A

1) susceptible HOST
2) agent
3) environment

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2
Q

True or False: Getting a microbe via kissing or interacting with in animal is a type of direct contact

A

True

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3
Q

What’s the difference between a biological and mechanical vector?

A

Biological vector: involves part of the pathogen lifecycle ; transmission via saliva or feces

Mechanical vector: passive transport of a pathogen on a vector’s body

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4
Q

True or False: The chain of transmission is: source for agent => portal of exit => mode of transmission => portal of entry

A

True

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5
Q

A continual source of infection is called a ____ of infection

A

reservoir

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6
Q

Human reservoirs are people who…..

A

1) have a disease
2) carry a pathogenic microorganism

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7
Q

____ are disease that affect wild and domestic animals and can be transmitted to humans

A

Zoonoses

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8
Q

True or False: Soil can be a non-living reservoir of C. botulinum, C. tetani, or fungi

A

True

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9
Q

True or False: Improperly prepared or stored foods can be nonliving reservoirs

A

True

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10
Q

Respiratory route, saliva, GI, skin to skin, blood-borne are examples of:
A. Vertical Spread
B. Horizontal Spread

A

B. Horizontal Spread

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11
Q

What is the most common and most difficult to control form of horizontal transmission?

A

Respiratory route

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12
Q

In the respiratory route of horizontal transmission, the ___ is equal to the ___

A

Po exit = Po entry

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13
Q

True or False: The larger a droplet nuclei (respiratory secretion or droplet), the longer it remains suspended in the air for longer than 20 minutes and can penetrate and attach to upper/lower respiratory tract

A

False - the SMALLER droplets remain suspended in the air for ~20 minutes

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14
Q

Which type of infectious disease is not transmitted (or at least not routinely transmitted) from person to person?

A

Non-communicable infectious disease

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15
Q

How can a non-communicable disease arise from one’s normal flora?

A

Aspiration of normal flora can lead to pneumonia

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16
Q

Provide an example of an environmental pathogens that can cause a non-communicable disease.

Provide an example of a zoonoses that can cause a non-communicable disease.

A

Environmental = Tetanus

Zoonoses = Rabies

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17
Q

Communicable disease are those transmissible from person to person. What are the three routes by which a disease can be spread person to person? Which is the most common?

A

1) Horizontal Spread - most common!
2) Vertical Spread
3) Zoonotic Spread

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18
Q

Which four conditions can be spread via salivary horizontal transmission?

A

EBV
Oral/genital herpes
CMV
Rabies

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19
Q

What are two horizontal routes by which GI pathogens can spread?

A

1) Fecal-oral route
2) Aerosolized vomitus

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20
Q

Which two microbes can be horizontally transmitted via: aerosolized vomitus?

A

H. pylori
Norovirus

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21
Q

True or False: Compromised skin allows for more pathogen access

A

True

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22
Q

True or False: Staph and Strep can be transmitted via: skin to skin contact

A

True

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23
Q

True or False: Herpes, HPV, and Dematophytoses can be transmitted via skin to skin contact

A

True

24
Q

Which two conditions are anthropod-borne (blood borne)?

A

Lyme disease (tick = vector)
Malaria (mosquito = vector)

25
Q

Which two pathogens can be transmitted from human to human via BOTH blood and body fluids?

A

1) Hep B/C
2) HIV

26
Q

Which mode of horizontal transmission is helminth (pin worm) typically acquired via?
A. Eye to Eye
B. Fomites
C. Genital
D. Autoinoculation

A

D. Autoinoculation

27
Q

HIV and CMV can be transmitted to a child via vertical transmission during:
A. transplacentally
B. parturition
C. breastfeeding

A

C. breastfeeding

28
Q

Gonococcal conjunctivitis and Strep B can be transmitted to a child via vertical transmission during:
A. transplacentally
B. parturition
C. breastfeeding

A

B. parturition

29
Q

True or False: HIV can be passed to child transplacentally

A

False - rubella virus can be transmitted this way

30
Q

___: infections spread from their natural reservoirs (often mammalian) to humans

A

Zoonosis

31
Q

True or False: Zoonosis can occur via direct transmission or through a vector

A

True
- Direct transmission (rabies)
- Vector (tick/lyme)

32
Q

Human to human spread from an initial zoonotic index can also occur, as in the case of ____

A

pneumonic plague

33
Q

____: the indirect effect of protection from infection of otherwise susceptible members of the population and, by extension, population as a whole as a result of presence of immune people

A

Herd Immunity

34
Q

True or False: Sufficient herd immunity can be a firewall to spread of an infection

A

True

35
Q

What three factors affect herd immunity?

A

1) Speed of spread - attack rate
2) Host Factors - past exposure? immunized?
3) Environment - hygiene

36
Q

What are three examples of immunity leading to herd immunity?

A
  1. Mumps
  2. Measles
  3. Pertussis
  • Both of the first two had high attack rates
37
Q

Which type of epidemic indicates: person to person spread or communicable disease?

A

Propagating epidemic

38
Q

What’s the difference between a sporatic and pandemic?

A

Sporadic is ocassional cases at irregular intervals in random locations

Pandemic is global

39
Q

_____: epidemic and endemic zoonoses, respectively

A

Epizootic and enzootic

40
Q

Which period of disease is critical for building a differential diagnoses and rule in/out potential sources of infection?

A

Incubation period

41
Q

What is a benefit of prolonged incubation periods?

A

Offers the opportunity for immunoprophylaxis or chemoprophylaxis (rabies, tetanus)

42
Q

_____: defined as the time between exposure to a pathogen and the appearance of the first signs and symptoms of disease

A

Incubation period

43
Q

___ has an incubation period of 1-2 days while _____ has an incubation period of 7-15 years
A. Norovirus
B. Rubella
C. Creutzfeldt-Jakob

A

Norovirus; Creutzfeldt-Jakob

44
Q

How does a higher inoculation dose affect the length of the incubation period?

A

Higher dose means shorter IP

45
Q

How does a faster replication time of an organism affect the length of the incubation period?

A

Fast replication means shorter IP

46
Q

If the site of inoculation is closer to the target tissue, the incubation periods will be ____

A

shorter

47
Q

Diseases are classified by ___ of occurence

A

frequency

48
Q

_____ are important considerations in build a differential diagnosis for an infectious disease. Also helps to identify populations at risk.

A

Risk factors

49
Q

_____: the occurrence of new cases during the time period being examined
A. Morbidity
B. Mortality rate
C. Prevalence/Point prevalence
D. Incidence/Incidence Rate

A

D. Incidence/Incidence Rate

50
Q

True or False: As incidence increases, so does the probability of getting the disease

A

True

51
Q

True or False: Incidence can increased within certain seasons

A

True

52
Q

____: total number of cases (old and new) in a population in a defined period
A. morbidity
B. mortality rate
C. prevalence

A

C. prevalence

53
Q

____: total # of deaths in a population due to given disease

____: total # of persons afflicted with infectious disease

A

Mortality Rate
Morbidity

54
Q

Which disease show prevalence (2001) and seasonality (summer)?

A

Lyme

55
Q

_____: the presence of (or rate of) an infection or disease in a population - a constant

A

Endemic/endemicity/endemic rate

56
Q

____: a statistically significant increase above the endemic rate of a disease

A

Epidemic

57
Q

What are the three type of epidemics?

A

1) Common source
2) Point source
3) Progressive/propagative