Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

HLTC27: Epidemiology > Lecture 10: Infectious Disease Epidemiology > Flashcards

Lecture 10: Infectious Disease Epidemiology Flashcards

1
Q

History of Infectious Disease

A

1350BCE - smallpox
1400s - bubonic plague
1500s - syphillis
1900s - smallpox, cholera, typhoid, tuberculosis

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

Susser’s Era in Epidemiology

A

Through different paradigms and intervention strategies, we have new understandings of infectious diseases.
Eras include:
- Sanitary
- Infectious Disease
- Chronic Disease
- Eco-epidemiology

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

Sanitary era (paradigm, analytic approach, prevention)

A

paradigm - miasma theory
analytic approach - clustering of mortality
prevention - sanitation

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

infectious disease era (paradigm, analytic approach, prevention)

A

paradigm - germ theory
analytic approach - laboratory
prevention - vaccinations

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

Chronic Disease era (paradigm, analytic approach, prevention)

A

paradigm - black box
analytic approach - risk ratios
prevention - host, agent, environment

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

Eco-epidemiology era (paradigm, analytic approach, prevention)

A

Paradigm - systems theory
analytic approach - determinants at many levels
prevention - contextual to molecular

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

system theory

A

there are a multitude of risk factors in various systems. Ex. transportation, government, healthcare, etc.

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

Infectious disease

A

An illness due to a specific infectious agent or its toxic products.
Arises through transmission of agent/toxic product from infectious person/animal/reservoir to a susceptible host.

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

How can transmission happen?

A
  • directly, from other infected animals/humans
  • indirectly, from intermediate host, vector, or the environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Susceptible

A

uninfected, but able to become infected if exposed

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

Infectious

A

infected and able to transmit infection to other susceptible individuals

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

Immune

A

possessing cell-mediated or humoral or antibody protection against an infection

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

diseased/clinical infection

A

presence of clinical signs of pathology (A disease that has recognizable clinical signs and symptoms)

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

Latent infection/subclinical infection

A

Remains in the body but you are not infectious

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

Carrier

A

Protracted infected state with shedding of the infectious agent.

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

Epidemic

A

excess in occurrences of cases beyond of what is normally expected in a community or region

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

Outbreak

A

an epidemic limited to localized increase in the incidence of a disease

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

Endemic

A

The constant presence of a disease or infectious agent within a given geographic area or population group

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

Pandemic

A

An epidemic crossing international boundaries and affects many people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Pathogens

A
  • bacteria
  • virus
  • chemical toxins
  • parasitic (multi-cell)
  • Fungal
  • Protozoa
  • Prions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Bacteria

A
  • fatty membrane contains DNA and cellular machinery
  • obtain energy from sugars, fats, and proteins
  • live and multiply outside of host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Different Shapes of Bacteria

A

bacilli - rod shape
cocci - round
spirochete - spiral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

virus

A
  • not affected by antibiotics
  • smallest infectious disease agent
  • thin protein coating around genetic material
  • requires energy from host cells
  • cannot replicate outside host cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Chemical toxins

A
  • organic and inorganic
  • allergens, carcinogens, teratogens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Parasitic (multi-cell)
- defined nucleus - single or multi-celled - ex. malaria, head lice
26
Fungal
includes yeast infections, candida
27
Protozoa
- single cell organisms - can be free-living or parasitic in nature - transmission - live in a human's intestine; fecal-oral route
28
Prions
- relatively new discovery - non-living - infectious agent with protein-like qualities - thought to be responsible for mad cow disease - difficult to disinfect - Ex. TSEs
29
Transmission Routes
Direct Transmission Indirect Transmission
30
Direct Transmission Routes
- mucous membrane to mucus membrane (STD) - Across placenta - Transplants - skin to skin - Sneezes, coughs
31
Indirect Transmission Routes
- water-borne - proper air-borne - food-borne - vectors - objects
32
Six-Link Chain of Infection
These interactions cause communicable disease to occur: 1. Pathogens 2. Reservoir 3. Portal of Exit 4. Transmission 5. Portal of Entry 6. Susceptible Host
33
Pathogens (Definition and public health approach)
- virus, bacteria, or parasite that causes disease in humans - kill agent (antibiotics)
34
Reservoir (definition and public health approach)
- location which pathogen lives and reproduces - eliminate reservoir (remove garbage)
35
Portal of Exit (Definition and public health approach)
- route pathogen takes to leave infected host - knowledge to understand transmission and control
36
Transmission (Definition and Public Health Approach)
- method of traveling from reservoir/infected host to susceptible host - block movement of pathogen (quarantine)
37
Portal of Entry (Definition and Public Health Approach)
- route pathogen enters host - block point of entry (mask)
38
Susceptible host (Definition and Public Health Approach)
- entry into host that is not immune - improve resistance (vaccination)
39
Characteristics of Agent
- toxicity, virulence, infectivity - susceptibility to antibiotics - ability to survive outside body
40
Characteristics of Environment
- climate - physical structures - population density - social structure
41
Characteristics of Host
- age - prior exposure - susceptibility - co-infection - immune response
42
Interventions for agent
- eradicate - genetically modify
43
Interventions for environment
- housing quality - sanitation, water - prevention services
44
Interventions for Host
- treat, isolate - immunize - nutrition
45
Age-environment intervention
- remove breeding grounds - improve sanitation
46
Host-environment intervention
- educate - change activity patterns - quarantine
47
Host-agent intervention
- protect - educate - alter exposure
48
Surveillance of Infectious Diseases
- influence decreased 2020-2021 - peaks end of december and early january - increasing after that - STIs have increased such as Gonorrhea and Chlamydia
49
Coronaviruses
group of viruses that are common in humans and are responsible for up to 30% of common cold
50
Outbreaks that have occurred due to coronaviruses
SARS (2003) MERS (2012)
51
COVID-19 Seroprevalence in Ontario
- PHO created the COVID-19 serosurveillance program - see what proportion of the Ontario population was infected with COVID and developed the antibodies for it
52
Serology Testing
a lab test that measures the antibodies specific to Covid-19 (looks as the presence or levels of antibodies)
53
Investigation and Control of Epidemics/Pandemics
1. Investigation 2. Identifying cases 3. Management and Control 4. Surveillance and Response
54
Principles of Surveillance
- incidence and prevalence - case-fatality - mortality rate and premature mortality - bed-disability days - medical costs - preventability - epidemic potential - information gaps on new diseases
55
Sources of Data
- mortality an morbidity - hospital records - laboratory diagnoses - outbreak reports - vaccine utilization - sickness absence report - biological changes in agent, vectors, or reservoirs - blood banks
56
Factors that Influence Effectiveness of Surveillance Systems
- Number of conditions (fewer) - Amount of information per case (little) - Burden on reporter (small) - Decision-Makers' interest in surveillance data (high) - goals for surveillance (clear and support) - reporting strategy for serious but common conditions (enough to meet goals) - usefulness of data locally (high) - use is limited to analysis of data and archiving (data are well used) - usefulness to decision-makers for prevention action (high)
57
Mathematical Models of Infectious Disease Transmission Dynamics
Systematic way of identifying and applying assumptions to data on disease transmission to quantify how an epidemic may evolve.
58
What do mathematical models help with?
- Estimating transmission parameters - effectiveness of interventions - predict cost effectiveness of interventions
59
Reproductive Rate, R
Average number of new infections caused by 1 infected individual.
60
Basic Reproductive Rate, R0
in an entirely susceptible population > 1 = epidemic 1 = endemic < 1 = infection dies out
61
Effective Reproductive Rate, R
In a population where <100% is susceptible. = proportion susceptible x R0
62
Hallmarks of an epidemic
1. number of infections increase exponentially during the early phase 2. epidemic curve is unimodal and peaks when the susceptible pool has been sufficiently depleted (Rt < 1)
63
Calculating R0
R0 = BcD B = probability of transmission per contact c = contact rate D = duration of infectivity
64
SIR model
People can be in one of three states S - susceptible to the infection I - infected/infectious R - recovered/immune
65
Assumptions for the SIR model
- fixed population - latent period is 0 - infectious period = disease period - after recovery, individuals are immune
66
Herd Immunity
The proportion of the population that need to be immune in order to stabilize an infectious disease. HIT = (R0 - 1) / R0 or HIT = 1 - (1/R0)
67
Things to consider when interpreting the herd immunity number
virulence of the disease re-emergence susceptibility interventions in place

HLTC27: Epidemiology (5 decks)

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