Disease Detectives

Question 1

asymptomatic

Answer 1

Showing no signs or symptoms, although can be carrier of disease

Question 2

cluster

Answer 2

An aggregation of cases over a particular period closely grouped in time and space, regardless of whether the number is more than the expected number

Question 3

elimination

Answer 3

Reduction to zero of a disease in a defined geographical area due to deliberate efforts. This requires continued intervention measures.

Question 4

endemic disease

Answer 4

Present at a continuous level throughout a population/geographic area; constant presence of an agent/health condition within a given geographic area/population; refers to the usual prevalence of an agent/condition.

Question 5

epidemic

Answer 5

Large numbers of people over a wide geographical area are affected.

Question 6

etiology

Answer 6

Study of the cause of a disease.

Question 7

fomite

Answer 7

A physical object that serves to transmit an infectious agent from person to person. An example of this is lice on a comb. The comb is the fomite and the lice are the agent that can make your hair itch.

Question 8

latrogenic

Answer 8

An illness that is caused by medication or a physician.

Question 9

incubation period

Answer 9

Time in between when a person comes into contact with a pathogen and when they first show symptoms or signs of disease.

Question 10

index case

Answer 10

First patient in an epidemiological study (also known as patient zero or primary case).

Question 11

morbidity

Answer 11

rate of disease in a population

Question 12

mortality

Answer 12

rate of death in a population

Question 13

nosocomial disease

Answer 13

An infection that is acquired in a hospital

Question 14

outbreak

Answer 14

More cases of a particular disease than expected in a given area or among a specialized group of people over a particular period of time.

Question 15

pandemic

Answer 15

An epidemic occurring over several countries or continents and affecting a large proportion of the population.

Question 16

plague

Answer 16

A serious, potentially life-threatening infectious disease that is usually transmitted to humans by the bites of rodent fleas. It was one of the scourges of our early history. There are three major forms of the disease: bubonic, septicemic, and pneumonic.

Question 17

risk

Answer 17

The probability that an individual will be affected by, or die from, an illness or injury within a stated time or age span. Risk of illness is generally considered to be the same as the Incidence (see below) and the terms are used interchangeably. Age-span is not usually a consideration in this usage. Risk of death from a particular illness is expressed as the Case Fatality Rate (Number deaths due to a disease/Number with the disease) or the Cause-specific Mortality Rate (Number deaths due to a disease/Number in population). Age span is a more common consideration in this last usage.

Question 18

surveillance

Answer 18

The systematic and ongoing collection, analysis, interpretation, and dissemination of health data. The purpose of public health surveillance is to gain knowledge of the patterns of disease, injury, and other health problems in a community so that we can work towards their prevention and control.

Question 19

symptomatic

Answer 19

showing symptoms or signs of injury

Question 20

vector

Answer 20

An animal that transmits disease but is not the cause of the disease itself. For example, a mosquito is a vector for malaria.

Question 21

zoonosis

Answer 21

An infectious disease that is transmissible from animals to humans.

Question 22

incidence (of illness)

Answer 22

he number of new instances of disease in a population over a given time period. It is expressed as “X cases/Y population/ Z time”.

Question 23

prevalence

Answer 23

the number of affected persons in the population at any given point in time. It is expressed as “X cases/Y population”. There are two major ways in which prevalence is measured: period prevalence and point prevalence

Question 24

point prevelance

Answer 24

snapshot of the population and its rate of a certain disease at a point in time

Question 25

period prevalence

Answer 25

tracks the prevalence over a certain duration

Question 26

13 steps to investigating an outbreak

Answer 26

1. Prepare for field work - Research and Supplies, Official Arrangements, Safety Protocols, and Contacts
2. Establish the Existence of an Outbreak - Consider Severity, Potential for Spread, Public Concern, and Availability of Resources
3. Verify the Diagnosis - Verify Procedures and Eliminate Experimental Error (and Other Errors/Biases, for That Matter)
4. Construct a Working Case Definition
5. Find Cases Systematically and Record Information - Time: Tables, Epi Curves; Place: Geographical Extent of Disease & Spot Map; Identify By Demographic Information or Exposures to Risk Factor
6. Describe and Orient the Data in Terms of Person, Place, and Time - Descriptive Epidemiology
7. Develop Hypotheses (Agent/Host/Environment Triad) = Chain of Transmission
8. Evaluate Hypotheses - Analytical Studies (MUST Have a Control Group)
9. Refine Hypotheses if Necessary
10. Compare and Reconcile with Laboratory and/or Environmental Studies
11. Implement Control and Prevention Measures (ASAP!)
12. Initiate or Maintain Surveillance - Monitor Implementation: Track New Cases, Check the Outbreak’s Spread Outside Targeted Area, Control and Change if Needed
13. Communicate Findings - Reports, To Important People and Public

Question 27

passive surveillance

Answer 27

Diseases are reported by healthcare providers. This type of surveillance, though simple and inexpensive, is often limited by incomplete reporting and quality variation in reporting

Question 28

active surveillance

Answer 28

Health agencies contact health provers seeking reports. This ensures more complete reporting of conditions. Active surveillance is often used with a specific epidemiological investigation or during an outbreak

Question 29

syndromic suveillance

Answer 29

The syndrome of the disease is monitored as a proxy for the disease. The syndrome must be infrequent and severe enough to warrant investigation of each identified case, and must be unique. This form of surveillance is often used when timeliness is key, diagnosis is difficult or time-consuming, or when detecting and defining the scope of an outbreak.

Question 30

sentinel surveillance

Answer 30

Professionals selected to represent a specific geographic area or group report health events to health agencies. This is used when high-quality data can’t be obtained through passive surveillance. It involves monitoring trends or key health indicators and a limited network of reporting sites. Advantages include being able to implement intervention earlier and not being as reliant on doctors to diagnose disease. One downside to sentinel surveillance is that it’s not as effective for detecting rare diseases or diseases that occur the outside the catchment areas of the sentinel sites.

Question 31

Hill’s Criteria for Causation

Answer 31

1. Strength of Association - relationship is clear and risk estimate is high
2. Consistency - observation of association must be repeatable in different populations at different times
3. Specificity - a single cause produces a specific effect
4. Alternative Explanations - consideration of multiple hypotheses before making conclusions about whether an association is causal or not
5. Temporality - cause/exposure must precede the effect/outcome
6. Dose-Response Relationship - an increasing amount of exposure increases the risk
7. Biological Plausibility - the association agrees with currently accepted understanding of biological and pathological processes
8. Experimental Evidence - the condition can be altered, either prevented or accelerated, by an appropriate experimental process
9. Coherence - the association should be compatible with existing theory and knowledge, including knowledge of past cases and epidemiological studies

Question 32

convalescent carriers

Answer 32

Humans are also capable of spreading disease following a period of illness, typically thinking themselves cured of the disease

Question 33

incubatory carrier

Answer 33

When an individual transmits pathogens immediately following infection but prior to developing symptoms

Question 34

chronic carrier

Answer 34

Someone who can transmit a disease for a long period of time

Question 35

genetic carrier

Answer 35

has inherited a disease trait but shows no symptoms

Question 36

transient/temporary carrier

Answer 36

Someone who can transmit an infectious disease for a short amount of time

Question 37

advantages of Trial study design

Answer 37

most scientifically sound, best measure of exposure

Question 38

disadvantages of trial study design

Answer 38

time consuming, unethical for harmful exposures, most expensive

Question 39

advantages for cohort study design

Answer 39

Most Accurate Observational Study
Good Measure of Exposure
Correct Time Sequence
Good for Rare Exposures
Easy Risk Calculation

Question 40

disadvantages for cohort study design

Answer 40

Time Consuming
Expensive
Bad for Rare Diseases
Possible Loss of Follow-up

Question 41

advantages for case-control study design

Answer 41

Can Study Rare Diseases
Relatively Less Expensive and Relatively Fast
Good for Rare Diseases
Good for Long Latency Periods

Question 42

disadvantages of case-control study design

Answer 42

Possible Time-Order Confusion
Error in Recalling Exposure
Only 1 outcome

Question 43

advantages of cross-sectional study

Answer 43

Fastest
Least Expensive
Good for More Than 1 Outcome

Question 44

disadvantages of cross-sectional study design

Answer 44

Possible Time-Order Confusion
Least Confidence in Findings