Brainscape's Knowledge GenomeTM

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


See full index

Epidemiology > Global Health - Infectious Disease > Flashcards

Global Health - Infectious Disease Flashcards

1
Q

What are 3 origins of human infections?

A
  1. Inherited from our ancestors
  2. Acquired from wildlife
  3. Acquired from livestock
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the fraction of transmission by animal reservoirs and why?

A

60-70% (2 and 3)
Animal reservoirs = zoonosis
Humans increasingly involved due to interference with animals and because we are a dominant species

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

What are some world changes in transmission of infectious disease?

A
  1. Increasing population density
    Faster transmission
    Each transmission event is opportunity for increased rate of evolution
  2. Migration of people allows faster transmission as environment is changing for virus very quickly so must adapt to selection pressure
  3. Airplane travel takes -24hrs (incubation period for most microorganisms)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is epidemiology?

A

ability to quantify disease occurrence in populations

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

What is a case?

A

person with the disease, health disorder of suffering from the event of interest

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

How is prevalence calculated?

A
  • frequency of disease in a population at a point in time

- it is a proportion: number of cases/number of people in population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does prevalence measure?

A

Measures burden of disease in a population from a cross sectional study
It compares the burden of chronic disease between populations
Prevalence = ALL CASES

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

What does incidence measure?

A

Number of new cases of disease within specific time interval
It is a probability/risk that individual will develop disease in that specific time period
Incidence = NEW CASES

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

What does prevalence depend on?

A

Number of new cases (incidence) and time they remain cases before death/recovery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is incidence calculated?

A

define time period
define total population at risk (denominator)
need an accurate test to define a true cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the challenge of designing a test to define a true case?

A

Easy for infections with short time period

But chronic disease (HIV hard to find positive antibody test that can identify new infection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does incidence influence policy makers?

A

When incidence near 0, outbreak over

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

How can incidence stay same but prevalence increase?

A

People with condition are kept alive e.g. HIV treatment

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

What is mortality?

A

number of deaths from specific disease condition in given time period
deaths from disease in given time period/population at start of time period

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

What does it mean if the mortality = incidence?

A

Epidemic is stable

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

What is the contradiction with reduced mortality with HIV?

A

More people alive with antiretroviral therapy
Mortality reduces - people alive longer
Transmit virus to sexual partners, babies causing incidence to rise
Prevalence also increases as people not dying

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

Explain the relationship between prevalence and mortality?

A

Define prevalence and mortality
Is treatment confers survival benefit (ART for those living with HIV), mortality falls and prevalence increases
For rapidly fatal diseases (Ebola) rapid mortality, large number of cases but low prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is morbidity?

A

number of cases of ill health, complications and side effects attributed to particular condition over particular time period

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

What is the difference between mortality and morbidity?

A

morbidity - state of being diseased/unhealthy i.e. incidence of ill health in population
mortality - number of people who died i.e. incidence of deaths in population

20
Q

Unit of measurement for morbidity?

A

Scores/predicted morbidity assigned to ill patients (APACHE II, SAPS II/III, GCS, PIM2, SOFA)
Help decide treatment/medicine that should be administered
Useful to compare two sets of patients/different time points in hospitals

21
Q

Unit of measurement for mortality?

A

Expressed as number of deaths/1000 per year

22
Q

Where is the highest death rate?

A

Swaziland 30.83

Also high in Angola, Lesotho, Sierra Leone, Zambia

23
Q

What are the leading causes of death?

A 
Heart disease
Cerebro-vascular diseases
Respiratory infections 
HIV-AIDS
COPD
24
Q

What about the leading causes of mortality in third world countries?

A

58% reported due to malnutrition/deficiencies

25
Q

What are the leading causes of infectious disease?

A 
6
Lower respiratory infections
HIV/AIDS
Diarrhoeal diseases
TB
Malaria
Measles
26
Q

Where are infectious diseases the leading cause of death?

A

Sub-saharan Africa

27
Q

What is the importance of age standardised death rates?

A

The standardised mortality rate is a weighted average of the age-specific mortality rates per 100 000 persons, where the weights are the proportions of persons in the corresponding age groups of the WHO standard population.

Measure how many people die each year and numbers help authorities determine whether they’re focusing on right public health actions to reduce numbers of preventable deaths and disease

28
Q

SAR event (2003)

A

originated from bat in central asia

29
Q

West Nile Virus (1999)

A

originated from birds (crows/rooks), transmitted by mosquitoes (arbovirus)
high infection rate
low serious morbidity cases
vaccine in clinical trials

30
Q

HIV 1 - RNA virus

A

Epidemics increasing linearly, should level off
Integrase inhibitors used
RNA viruses have no proofreading mechanism which increases the chance of mutation and evolutionary progression

31
Q

Malaria

A

generation of genetic variability - mutation and recombination of different games, plasmid transfer
Plasmodium virus has multiple surface antigenic proteins. Each is synthesised different making it harder to target with vaccine

32
Q

MERS virus

A

originated from camels

high incidence in Middle East

33
Q

Ebola

A

Slow characteristic of transmission
Symptoms before highly infectious so patient can be placed in isolation
Highly contagious, rapidly fatal but can be prevented
Spread via direct contact with bodily fluids, contaminated surfaces
Frequent transmission to health care workers

34
Q

Public health measures for Ebola?

A

Identify, isolate and follow up contacts

Effective contact tracing and isolation for 21 days post contact

35
Q

Zika virus

A
  • initially isolated from rhesus monkeys
  • it is a flavivirus, transmitted by mosquitoes (arbovirus), also sexually transmitted

linked to children with microcephaly born to infected mothers
risk of infection in first trimester 1/100 to 1/100 over all trimesters
risk of Gullian-Barre syndrome in infected adults 4/100000

36
Q

How to indicate emergence of new infectious disease?

A
  • Indication from unusual clusters of morbidity/mortality in space and time
  • Identify aetiology (cause) - looking for homogeny in cases/study results worldwide
  • Develop diagnostic tests e.g. blood test, use antibodies, use QPCR by amplifying parts of virus to deterine genetic sequencing
  • Follow routes of infection
  • Ensure public aware of new information to introduce wide spread initiatives to avoid disease/take precaution
37
Q

What is the basic reproductive number?

A

Ro
= average number of secondary cases from the emergence of a single primary case
It determines incidence and prevalence of infection
If less than 1, extinction
More than more, suggests epidemic, increase transmission

38
Q

What factors affect Ro?

A
  • duration of incubation period
  • peak infectiousness
  • how quickly infectiousness decays
  • acquired immunity important
  • population data determines human movement and how this may affect disease progression
39
Q

What is the incubation period?

A

the period between exposure to an infection and the appearance of the first symptoms

40
Q

What is the effective reproduction number?

A

number of infections caused by each new case occurring at time, t

41
Q

Explain graph of rate of new infections against time

A

Rate increase slowly initially then adopts exponential steepness
This tails off as it exhausts the number of people susceptible to the virus/bacteria, downgrade in rate of infections. Vaccines also decrease rate.
Level of infection rises again as new mutation, selected advantage may initiate new epidemic

42
Q

What is the policy for the prevention and control of influenza?

A
  1. Minimise morbidity and mortality with fixed or variable budget
  2. Buy time for vaccine development
  3. Minimise epidemic duration, impact on economy
  4. Minimise peak prevalence below defined level and avoid collapse of healthcare systems
43
Q

What are the cause of much morbidity and mortality?

A

Neglected tropical diseases (NTDs)

44
Q

Examples of protozoan infections

A 
Leishmaniasis
African Trypanosomiasis (sleeping sickness)
45
Q

Examples of Helminth Infections

A 
Schistosomiasis
Lymphatic Filariasis (Elephantiasis)
Onchocerciasis (River Blindness)
Hookworm - soil transmitted
Dracunculiasis - Guinea worm
46
Q

Examples of bacterial infections

A

leprosy
trachoma
buruli ulcer

Epidemiology (15 decks)

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