Brainscape's Knowledge GenomeTM

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


See full index

Medical Microbiology > Epidemiology > Flashcards

Epidemiology Flashcards

1
Q

Why are models used?

A
  • as a representation of a system
  • to make predictions and generate new hypotheses
  • allows investigation of system properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is epidemiological model used for?

A

To consider the number of infections through time, with infection rate and removal rate

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

How is R0 calculated?

A

Rate of new infections/average infection duration

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

What are the 4 different mutation types?

A
  • Nucleotide only
  • Change amino acids
  • Insertions and deletions
  • Recombination and gene transfer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a phylogeny?

A

A diagram representing ancestral relationships among characters or genetic sequences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why are phylogenetic trees useful?

A
  • phylogeny is most complete representation of evolutionary relationships
  • provides a framework for asking scientific questions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Differences in replication and evolution speeds of RNA viruses, DNA viruses, and bacteria?

A

RNA viruses = fast but error prone
DNA viruses = slower and more conserved
Bacteria = very slow, but horizontal gene transfer can take place

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

Differences in genome size and mutation rate of RNA viruses, DNA viruses, and bacteria?

A

RNA virus = 8-30kb with 10-100 mutations per year
DNA virus = 20-200kb with 1-20 mutations per year
Bacteria = 4Mb with 0-1 mutations per year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the main points of rooted trees?

A
  • single node represents earliest point in time
  • have directionality as nodes can be ordered in terms of earlier or later
  • branch lengths are measured in substitutions per site
  • distance between nodes is represented along x-axis only
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the main points of unrooted trees?

A
  • no directionality, cannot tell if a node is earlier or later in time
  • distance along branches directly represents node distance, which is the genetic distance measured in substitutions per site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 3 things needed in order to build a tree?

A
  • sequence data
  • model of substitution
  • ability to determine branch order
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the order of substitution models from simplest to most complex?

A

Jukes-cantor, Kimura-2-parameter, HKY, TN93, GTR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the Jukes-cantor model?

A

Base frequencies are equal and all substitutions are equally likely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the kimura-2-parameter model?

A

Base frequencies are equal and transversions occur at different rates

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

What is the HKY model?

A

Unequal base frequencies and transitions and transversions occur at different rates

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

What is the TN93 model?

A

Unequal base frequencies, transitions and transversions occur at different rates, and different rates for different transition types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the GTR model?

A

Unequal base frequencies and all substitution types occur at different rates

18
Q

What is a clustering algorithm and an example?

A

A simple and fast method that progressively joins the 2 closest sequences or ancestral sequences

Eg. Neighbouring joining algorithm

19
Q

What is an optimisation algorithm and an example?

A

Defines an explicit score/goodness for each tree, trying to find the one tree which optimises inferion by swapping parts

Eg. Maximum likelihood

20
Q

What are generic clusters and why are they useful?

A
  • Sequences from samples which are genetically similar
  • Can determine who infected who
  • Genetically similar samples have recent time to most recent common ancestor (TMRCA)
21
Q

What are clusters and why are they useful?

A
  • are sequences from samples which are genetically similar
  • genetically similar sequences have recent time to most recent common ancestor
  • can be used to tell who infected who
22
Q

What are clusters and why are they useful?

A
  • are sequences from samples which are genetically similar
  • genetically similar sequences have recent time to most recent common ancestor
  • can be used to tell who infected who
23
Q

What is the degree of an individual? What is degree distribution?

A

The number of links an individual has. Degree distribution describes how connected individuals are in the network fragmentation

24
Q

Scale free network influence in epidemics?

A

Scale free network consists of long range interactions between few highly connected nodes (hubs), meaning epidemic can spread quickly

25
Q

What is antigenic shift?

A

2 or more strains of a virus combine to form a new subtype and cause a large outbreak in the population

26
Q

What is antigenic drift?

A

New strains persist and circulate in a population, accumulating mutations within the subtype

27
Q

What is epidemiology?

A

The study of infectious disease in populations

28
Q

What are the 3 key pieces of information that are needed in order to understand epidemiology of an infectious disease?

A
  • transmission biology
  • pathogenesis of infection
  • host demography and behaviour
29
Q

What is statistical epidemiology?

A

Tests of association and measurement of risk factors, includes cohort studies and case control studies

30
Q

What is mathematical epidemiology?

A

Representation of epidemiological processes, such as differential equation models and microsimulations

31
Q

What are microparasites?

A

Small parasites which multiply rapidly and directly within the definitive host

32
Q

What is the basic reproduction number R0?

A

R0 is the average number of secondary cases produced by a single primary case introduced into a large population of previously unexposed individuals

33
Q

What is the SLIR model?

A

A compartment model which divides the population into susceptible, latent, infectious and recovered

34
Q

In which ways does compartment model show us ways of stopping and reducing infection?

A
  • risk averse behaviours, avoiding contact due to illness (S/I)
  • quarantine or isolation (I)
  • vaccination (S)
35
Q

What is herd immunity?

A

The minimum fraction that must be immunologically protected by natural exposure or vaccination to reduce R0 below 1

36
Q

What is the definition of emerging infectious disease?

A

Diseases of infectious origin whose incidence in humans has increased within the last 2 decades or threatens to increase in the near future

37
Q

What is zoonoses?

A

Diseases which are naturally transmitted between vertebrate animals and humans

38
Q

What are the 4 stages of the pathogen pyramid and their respective R0 values?

A

Level 1 - exposure
Level 2 - infection R0=0
Level 3 - transmission 0<R0<1
Level 4 - epidemic spread R0>1

39
Q

Why are there no level 4 tick borne viruses?

A

There are no anthropophilic ticks

40
Q

RNA viruses and anyhropophilic vectors

A
  • 91 human RNA viruses transmitted by vectors, with 18 of these being level 3/4 carried by anthropophilic vectors

Medical Microbiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions