Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS2052 MICRO > WEEK 7: EPIDEMIOLOGY > Flashcards

WEEK 7: EPIDEMIOLOGY Flashcards

1
Q

What is epidemiology?

A
  • the study of occurrence, distribution, and control of disease in a population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What allows for the classification of a disease as endemic, epidemic/outbreak, or pandemic?

A
  • The FREQUENCY of disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does it mean if the disease becomes an epidemic?

A
  • If there is an expected INCREASE above the constant frequency in a give population (above endemic levels)
  • “the occurrence of disease in excess of what would normally be expected in a community or geographical data”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Can the word ‘outbreak’ mostly be used synonymously with epidemic?

A
  • YES!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What can the term outbreak also be used to describe?

A
  • An unexpected increase in frequency within a small part of the population.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a pandemic known as?

A
  • When there is an epidemic (increase in frequency) on a global scale
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Are the terms endemic, pandemic, and epidemic applicable with non-communicable diseases as well as pandemic diseases?

A
  • YES!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an ‘infectious disease’ defined as?

A
  • “Any change from a state of HEALTH in which part all of the host’s body cannot carry on its normal functions because of the presence of an infectious agent or its products” (Prescott’s Micro 10ed-moodle)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the epidemiologists definition of infectious disease?

A
  • “an illness due to a specific infectious agent or its toxic product that arises through transmission of that agent or its products from an infected person, animal or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector, or the inanimate environment:”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 main steps that are involved in epidemiology infectious disease?

A
  • Surveillence
  • Prevention
  • Control
  • Treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the patterns and determinants of diseases in a population?

A
  • WHERE and WHEN does a disease of interest appear \
  • Disease BUDREN in population
  • Common characteristics among cases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do epidemiologists aim to improve through looking at the patterns and determinants of disease?

A
  • Improve the preventive and control measures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 4 infectious disease agents?

A
  • Viruses
  • Bacteria
  • Fungus
  • Parasites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Does the risk of disease increase with populations size for infectious diseases?

A
  • YES
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Is a susceptible person infected or immune to an infectious disease?

A

-NO they are NEITHER infected nor immune

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the spread of infectious disease limited by in terms of the population?

A
  • The proportion of the population that is immune
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the pathogen rely on for the persitence of communicable diseases?

A
  • Repenishment of susceptible:
  • Newborns
  • Immigration
  • Waning of immunity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Was measles FINALLY controlled after it was discovered that new births were SUSCEPTIBLE to the disease?

A
  • YES!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When has a person been exposed to a pathogen (which conditions) ?

A
  • If the person has encountered the pathogen in a way that the person could become infected
  • e.g. Child sitting next to an influenza infected child for an hour is EXPOSED to the infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does an epidemiolopgical study begin with?

A
  • A case definition of the disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the case definition of a diasease?

A
  • Lab results
  • Clinical symptoms
  • Epidemiological links (e.g. someone who has never been to Africa)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the formula for incidence?

A
  • number of cases during a DEFINED time period (days, weeks, months or years)/ Population size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is the incidence of infectious disease UNDERESTIMATED?

A
  • A substnantial number of infections are subclinical

- A significant proportion of clinical cases DO NOT SEEK MEDICAL CARE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the formula for prevalence?

A
  • The total number of cases at a SPECIFIC time period / population size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the formula for prevalence incorperating incidence?

A
  • Prevalence= incidence * Average disease duration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can observational studies only be done for?

A
  • Infectious diseases (b.c. you can’t release a pathogen into the population and study it-ethical issues!)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a way to study the course and spread of diseases?

A
  • Analysing data collected from natural epidemics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are robust disease surveillence and meticulous medical records essential for?

A
  • Understanding and combating infectious diseases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Is disease surveillene more important for acute or chronic diseases?

A
  • Acute diseases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are 4 uses of epidemic curves?

A
  • Epidemic size
  • Case distribution (stratify by age, gender, symptoms)
  • Point source exposure of propagated epidemic (serial interval)
  • Identify impacts of events on disease spread
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is a hollow endemic known as?

A
  • Something that infects most of the people in the population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What does a line list involve?

A
  • Acquiring a lot of GP data and making epidemiological inferences (e.g. Age histogram)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is point source exposure and an example?

A
  • No or very little spread
  • One peak with all the cases occurring within one incubation period after exposure
    e. g. A food contamination outbreak –> one peak with all cases occurring within one incubation period after exposure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a popagated epidemic and an example?

A
  • Driven by person-person
  • MULTIPLE waves with PROGRESSIVELY TALLER peaks (each wave corresponds to the infections caused by the wave preceding it)
    e. g. measels epidemic in South Dakota (1970)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the ‘serial interval’?

A
  • The time interval between the peaks of successive waves in a propagated epidemic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the incubation period defined as?

A
  • The time from infection to symptoms onset
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What three ways can the incubation period vary?

A
  • Dose and route of infection
  • host factors (age, genetics, immunocompetence)
  • Pharmacological, prophylaxis and treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Is the incubation period for SARS patients 2003 typically right or left skewed?

A
  • Right skewed (positive skew)
39
Q

What is the incubation period used to predict in clinical management?

A
  • The disease severity (shorter incubation period is associated with severe complications)
  • To delay the onset of symptoms e.g. HIV by using antiretroviral therapies
40
Q

How is incubation period used in public health control (2 reasons) ?

A
  • To determine the QUARANTINE DURATION for suspected cases and contacts of confirmed cases
  • to interpret public health surveillence data
41
Q

What is the process of Quarantine?

A
  • Isolating the suspected cases and contacts from the community in case they have been infected BUT do not yet have the clinical or virologic evidence of infection
42
Q

What is one of the most epidemiologic characterisitcs of a communicable disease?

A
  • The transmissibility
43
Q

What two components are part of the transmissibility of a communicable disease (measureable)?

A
  • Secondary attack rate

- Reproducible number

44
Q

What is the measure of transmissibility starting with A?

A
  • Attack rate
45
Q

What is the attack rate?

A
  • The PROPROTION (prevalence) of a given exposed population that has been INFECTED by the pathogen
46
Q

What is the FORMULA for attack rate?

A
  • Cumulative no. of infections/ size of exposed population
47
Q

Over the course of an epidemic does the attack rate INCREASE or DECREASE?

A
  • Increases because more people get infected
48
Q

Does the attack rate describe how transmissible the pathogen is from person-person?

A
  • NO!
49
Q

What is used to try and give an indication of the transmissibility of a pathogen? (that is an improvement of attack rate)

A
  • Secondary attack rate
50
Q

What is the secondary attack rate?

A
  • The attack rate of the exposed susceptible population in a semi-closed setting after the introduction of an infected individual into this setting
  • Follow the persons family members over a week
51
Q

Is the secondary attack rate very accurate?

A
  • NO
52
Q

What is a true measure of transmission?

A
  • The reproductive rate (R)
53
Q

What is the reproductive rate?

A
  • A measure of how quickly a pathogen is being transmitted

- “ The expected number of SECONDARY cases generated by ONE infected case”

54
Q

What is R0 and what does it mean?

A
  • R0= Basic reproductive number
  • Describes the number of people infected by an infected person WITHOUT giving information on how long it takes for infections to occur
55
Q

What does the R0 indicate and is the population?

A
  • Indicates whether the invasion of the pathogen can give rise to an exponentially growing epidemic
  • Population is COMPLETELY SUSCEPTIBLE
56
Q

What does an R0 of <1 mean?

A
  • The epidemic will die out without exponential growth
57
Q

What does an R0 of >1 mean?

A
  • The pathogen can lead to an exponentially growing epidemic
58
Q

What does R0 change with?

A
  • Changes with space (environment) and time as the host immunity builds up
59
Q

Why is the incubation period always the most difficult timescale measure in a disease?

A
  • Bc. not sure when the person was actually infected
60
Q

What is generation time?

A
  • The time between successive infections in a chain of transmission (but infection event is DIFFICULT to observe directly or recall accurately)
61
Q

What is the serial interval?

A
  • the time between symptom onset of successive cases
62
Q

What is the time scale of a person-person disease transmission measured by and what is this an important determinant for? (2 things)

A
  • Generation time or serial interval

- Important determinant for the success of quarantine and isolation

63
Q

What does a shorter generation time or serial interval mean in terms of disease spread?

A
  • that the confirmed and probable cases would need to be IDENTIFIED and REMOVED from the population SOONER in order to prevent them from spreading the disease
64
Q

Is a generation time of 8 days like in SARS harder or easier to control?

A

-Easier to control

65
Q

Is a generation time of 2.5 days like in influenza harder or easier to control?

A
  • Harder
66
Q

What is the latent period defined as?

A
  • The time taken for a person to become infectious (e.g. time you start shedding a virus) after they have been infected.
67
Q

What is an important determinant of disease transmission?

A
  • the latent period
68
Q

Is isolation upon symptoms onset effective for preventing transmission?

A
  • NO
69
Q

What three factors make up the epidemiological triad?

A
  • Pathogen
  • Host
  • Environment
70
Q

What belongs under the umbrella of pathogen in the epidemiological triad?

A
  • replication rate
  • Antigenicity
  • Antiviral resistance
  • Virulence
  • Genetic diversity
71
Q

What belongs under the environment umbrella in the epidemiological triad?

A
  • transmission settings
  • reservoirs
  • climatic factors
  • socio-economic factors
  • interventions
    e. g. if it is humid the environment will harbor the virus longer
72
Q

What is the epidemiological triad?

A
  • The three main elements that determine the SPREAD of an infectious disease
73
Q

What belongs under the host umbrella in the epidemiological triad?

A
  • Demographics
  • Contact patterns
  • pathogenesis
  • natural history
  • Immunity and severity
74
Q

What are the 3 basic components of infection?

A
  • Probability of infection
  • Severity of infection
  • Level of contagiousness
75
Q

What are the three main outcomes after being exposed to an infection?

A
  1. No infection
  2. Asymptomatic or subclinical infection
  3. Clinical infection including severe infection
76
Q

What may the severity of the pathogen depend on?

A
  • the dose of the pathogen experienced by the host
77
Q

When a person swallows a larger dose of Salmonella than someone else, is the incubation period shorter or longer?

A
  • Shorter –> bc. more particles ingested (more severe)
78
Q

Was the Pr of cholera infection larger with those who ingested a larger amount of bacteria?

A
  • Yes
79
Q

Does the viral load matters for transmission?

A
  • YES

- higher viral load–> higher average transmission rate e.g. HIV

80
Q

What can the genetics of the pathogen determine?

A
  • The severity of infection
81
Q

What are three types of virulence factors?

A
  • Adherins (attaching)
  • Invasins (invading)
  • Toxins (poisoning)
82
Q

What type of adherins can make a urinary tract infection more likely?

A
  • Adherins that promote attachment to the urinary tract
83
Q

What is a pathogen that can live in the nasopharynx of someone who is healthy, then move to sterile areas (middle ear, lung) to cause disease?

A
  • S. pneumoniae
84
Q

What are the dose and genetics of a pathogen shaped by?

A
  • Evolution
85
Q

What is pathogen evolution defined as?

A
  • Changes in pathogen populations overtime that arise due to natural selection
86
Q

For natural selection to occur, what two factors must be present?

A
  • Genetic variation

- Differential reproductive success of different genetic types

87
Q

What are the three forms of horizontal gene transfer?

A
  • transformation (release of free DNA-antibiotic resistance gene)
  • Transduction (phage injecting DNA)
  • Conjugation ( sex pilus)
88
Q

What was the Myxomatosis virus in rabbits used to understand and what did it show?

A
  • Whether the rabbits evolved resistance overtime or if the virus becomes less virulent
  • The rabbits showed resistance as before the outbreak, there was a large population–> then after very small but then it started to increase again
89
Q

What is the viral load of HIV (in part) determined by?

A
  • the genetic properties
90
Q

Are strains of HIV and Myxoma with a higher replicative fitness or lower fitness preferred?

A
  • Strains with a LOWER fitness
  • Bc. they keep the host alive for longer but with lower chances of transmission
  • (Strains with higher fitness are more transmissible but kill the host faster)
91
Q

What level do pathogens evolve the average viral load towards?

A
  • A level that BALANCES transmissibility with host survival
92
Q

What is an important trait of viruses a part from viral load?

A
  • Variation in antigenicity (changing/shedding the major antigens)
93
Q

What is a factor that affects the tendency to engage in activities that can transmit specific types of infection?

A
  • Age

BMS2052 MICRO (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions