outbreak investigation

Question 1

this is when a disease shows up more often than normal in a specific area.

Answer 1

epidemic
- also called disease outbreaks

Question 2

Why is reliable surveillance important in managing epidemics?

Answer 2

It helps determine the usual rates of disease, making it possible to identify when rates are considerably elevated.

Question 3

surveillance is the entire process of ___, ___, ___ and ___ data on the ____ and the ____

Answer 3

collecting
analyzing
interpreting
record data

incidence of death, diseases and injuries
prevalence of certain conditions

*it is important to promote and safeguard the public health

Question 4

this is considered the foundation of disease control and efforts

Answer 4

surveillance

Question 5

Who is responsible for disease surveillance in the U.S.?

Answer 5

The CDC (Centers for Disease Control and Prevention).

Question 6

it is the federal agency responsible for the surveillance of most types of acute diseases and the investigation of outbreaks.

Answer 6

the Centers for Disease Control
and Prevention (CDC)

Question 7

When does the CDC handle disease outbreaks?

Answer 7

if requested by a state or if an outbreak has the potential to affect more than one state.

Question 8

Who handles disease outbreaks within a single state?

Answer 8

The state government.
- they manage health issues within their own boarders

Question 9

how does the data for disease surveillance are passed down

Answer 9

from local and state governments to the CDC
- which evaluates the data and works with the state and local agencies about further investigation and control of any problems discovered

Question 10

What allows the federal government to respond to interstate disease outbreaks?

Answer 10

The U.S. Constitution’s jurisdiction over interstate commerce.

Question 11

What happens if a disease has interstate implications?

Answer 11

The CDC is a first responder and acts immediately without waiting for a state request

Question 12

federal gov vs state gov

Answer 12

federal gov: (CDC)
Handles outbreaks that start in one state and spread to others or could spread to others.

state gov:
Take care of outbreaks that stay within their own state.

Question 13

outbreaks that originated in one state and have spread to other states or have the potential to do so

Answer 13

interstate implications

Question 14

how to create a surveillance system

Answer 14

*this is the first step in creating a surveillance system

1. development of surveillance system requires clear objectives regarding the disease or conditions to be covered
   (infectious disease, side effects of vaccines, elevated leads)
2. to clarify goals: objectives for each surveillance item should be clear, including surveillance of an infectious disease. (measure vaccine effectiveness, check for side effects, track progress on health goals).

Question 15

it is a set of rules used to decide if someone has a particular disease.

Answer 15

case definition

Question 16

case definition is based on

Answer 16

Clinical findings: Symptoms or signs of the illness.

Laboratory results: Test results that confirm the disease.

Epidemiologic data on time: Information about when, where, and who is affected.

Characteristics of affected persons:

Question 17

What are the two types of surveillance intensity?

Answer 17

Active: Proactively collecting data.
- more labor intensive and costly
- seldom done on a routine basis
[recording of diseases by periodically scouting for information, actively seeking out cases and data.]

Passive: Waiting for reports to come in.
- most surveillance is conducted on a routine basis
[recording of diseases that come to knowledge, typically through routine reporting mechanisms.]

Question 18

What are the two possible durations for surveillance?

Answer 18

Ongoing: Continuous monitoring.
Time-limited: Monitoring for a specific period.

Question 19

What kinds of data analysis should be planned?

Answer 19

analysis of incidence
prevalence
case fatality
costs, or quality-adjusted life years.

Question 20

How should the findings of the surveillance system be shared?

Answer 20

Through the internet
Other publication venues

Question 21

Why is a pilot test important?

Answer 21

To test the system in a small area before full implementation.

Question 22

What should be done after the system becomes operational?

Answer 22

Continually evaluate and improve the system.

Question 23

who are given forms and instructions to record any reportable disease cases they come across.

Answer 23

passive surveillance

physicians
clinics, labs
hospitals
* they are asked to report cases of diseases.
* healthcare providers report diseases based on what they notice, without being actively followed up.

Question 24

Requires direct follow-ups with healthcare providers to gather data on diseases.

Answer 24

active surveillance
(phone calls, visits, or electronic contacts)
- Public health authorities actively reach out to institutions regularly (often weekly) to gather required data.

Question 25

Infectious vs. Non-Infectious Diseases

Answer 25

Infectious diseases are reported more rapidly. Other diseases (like injuries, chronic conditions) have slower and less widespread reporting systems. These systems develop based on specific problems.

Question 26

Challenges of Disease Surveillance

Answer 26

Funding & Support: Surveillance systems need strong government funding and support to start and maintain. Most systems begin as small-scale demonstration projects before expanding nationwide. Cancer Registries: While some states have cancer registries, there is no national registry for cancer in the U.S.

Question 27

Used to track fatal diseases, but they often have inaccuracies.

Answer 27

Death Certificates - They are not reported quickly enough for detecting disease outbreaks.

Question 28

What percentage of disease cases are reported in passive surveillance?

Answer 28

The percentage varies but can range from 30% to 62% of cases.

Question 29

What is the purpose of baseline data in disease surveillance?

Answer 29

To track usual disease patterns, so unusual changes can be noticed and investigated. baseline rates and patterns of diseases can be known only if there is a regular reporting and surveillance system

Question 30

how can the epidemiologists study the patterns of disease

Answer 30

by the time and geographic location of cases the characteristics of the person involved

Question 31

A long-term trend that shows how a disease changes over time, often revealing bigger public health issues.

Answer 31

secular trend (long-term)

Question 32

The percentage of people who die from a disease.

Answer 32

case fatality ratio

Question 33

Regular reporting and surveillance help track usual disease patterns.

Answer 33

Baseline Data - Unusual changes in patterns can signal outbreaks or issues with reporting.

Question 34

When do respiratory diseases like flu typically peak?

Answer 34

In winter and early spring, when people spend more time indoors.

Question 35

Why do insect-borne diseases peak in summer?

Answer 35

Insects like mosquitoes and ticks are more active in warm weather, and people are outside more.

Question 36

What is the peak season for waterborne gastrointestinal diseases and the peak for outbreaks attributable to recreational water?

Answer 36

May to August, as warm weather helps bacteria grow in food and water. June to October for the recreational water.

Question 37

When do recreational drownings occur most frequently?

Answer 37

On weekends, when more people are swimming.

Question 38

what does it depends when many infectious diseases show a strong seasonal variation, with periods of highest incidence

Answer 38

usually depending on the route of spread

Question 39

how to determine the usual number of cases or rates of disease

Answer 39

epidemiologists must therefore incorporate any expected seasonal variation into their calculations.

Question 40

this disease have a much higher incidence in the winter and early spring in the Northern Hemisphere.

Answer 40

infectious disease that are spread by the respiratory route

Question 41

this disease have a strong predilection for the summer or early autumn

Answer 41

disease that are spread by insect or arthropod vectors

Question 42

this disease are most common in the summer, partly because of the ability of the organisms to multiply more rapidly in food and water during warm weather

Answer 42

Infectious diseases that are spread by the fecal-oral route

Question 43

advantage of using the epidemiologic year when plotting the incidence of a disease

Answer 43

it puts the high-incidence months near the center of a graph and avoids having the high-incidence peak split between the two ends of the graph, as would occur with many respiratory diseases if they were graphed for a calendar year. [Using the epidemiologic year helps to group the highest disease rates in the middle of a graph, making it easier to see patterns without splitting the peaks across the edges, as can happen with diseases that peak at different times of the year.]

Question 44

outbreaks that originated in one state and have spread to other states or have the potential to do so

Answer 44

Interstate Implications

Question 45

outbreaks confined within one’s state borders

Answer 45

Intrastate Implications *each state government has jurisdiction over these matters

Question 46

it allows epidemiologists to detect deviations from usual patterns, prompting them to investigate whether an epidemic is occurring or if other factors (like reporting changes) are responsible for observed changes.

Answer 46

Establishing Baseline Data in disease surveillance

Question 47

this analyze trends in specific times of the year, often attributing them to disease detection or reporting, and records significant health events throughout the years.

Answer 47

Evaluating Time Trends in disease surveillance

Question 48

refers to the periodic increase or decrease in disease incidence, usually depending on the disease's route of spread, with certain diseases peaking during specific seasons.

Answer 48

Seasonal Variation in infectious diseases

Question 49

for a given disease runs from the month of lowest incidence in one year to the same month in the next year.

Answer 49

Epidemiologic Year for example, from July 2024 to July 2025.or example, from July 2024 to July 2025.

Question 50

What does Thermophilic mean?

Answer 50

hermophilic refers to organisms that are attracted to or thrive in high-temperature environments, derived from "thermo" (temperature) "philic" (attracted to).

Question 51

It involves classifying health crises under specific levels (endemic, epidemic, pandemic) and setting the epidemic threshold for a disease in relation to its location of origin.

Answer 51

Identification and Documentation of Outbreaks

Question 52

How is surveillance used in the context of bioterrorism?

Answer 52

to locate and monitor bioterrorism, tracking diseases like anthrax, botulism, plague, smallpox, tularemia, and viral hemorrhagic fever.

Question 53

What is the meaning of "Bio" and "Terrorism" in the context of bioterrorism?

Answer 53

"Bio" means life "terrorism" refers to acts of injustice or violence intended to cause fear or harm.

Question 54

Why is surveillance important after introducing public health interventions?

Answer 54

helps determine if major interventions, like new vaccines, have achieved the intended changes in disease patterns. It tracks effectiveness and identifies failures.

Question 55

What are signs of failure in public health interventions?

Answer 55

A lack of change in disease rates An increase in disease rates after an initial decrease An increase in disease within a recently vaccinated group

Question 56

How does data on disease patterns help in setting disease control priorities?

Answer 56

Data on disease patterns for the current time and recent past helps government and voluntary agencies establish priorities for disease control efforts. The severity of the disease, which can be determined through good surveillance, is a critical factor.

Question 57

What is important to check when setting disease control priorities?

Answer 57

It is important to check the frequency count or quantity of who is sick to help establish control priorities.

Question 58

How does the study of changing disease patterns help epidemiologists?

Answer 58

By studying the patterns of occurrence of a particular disease over time in populations and subpopulations, epidemiologists can better understand how disease patterns are changing.

Question 59

the unusual occurrence of a disease in a population or geographic area.

Answer 59

Epidemic

Question 60

refers to when a disease is consistently present in a particular locale at a constant level.

Answer 60

Endemic

Question 61

is a disease outbreak in an animal population.

Answer 61

Epizootic

Question 62

it is when a disease is present at a particular locale for a specific animal species at a constant level.

Answer 62

Enzootic

Question 63

is a key epidemiologic indicator used to investigate acute disease outbreaks, helping to identify exposures that contributed to illness.

Answer 63

Attack Rate

Question 64

attack rate formula

Answer 64

index card

Question 65

What is the first step in investigating an epidemic?

Answer 65

establish the diagnosis, which involves identifying the nature of the illness or problem by examining the symptoms.

Question 66

Why is establishing the diagnosis crucial in investigating an epidemic?

Answer 66

Establishing the diagnosis is crucial because many cases are resolved by correctly identifying the disease, which may show that the disease occurrence is not unusual after all.

Question 67

What is the Epidemiologic Case Definition?

Answer 67

The epidemiologic case definition is a list of specific criteria used to determine whether a person has the disease of concern. It is not the same as a clinical diagnosis but provides consistent criteria for epidemiologic investigations.

Question 68

Why is the case definition important in an epidemic investigation?

Answer 68

The case definition is especially important if the disease is unknown, as it helps establish consistent criteria for identifying cases before definitive diagnoses are available.

Question 69

What are some criteria for establishing an epidemiologic case definition?

Answer 69

A total eosinophil count greater than 1000 cells/uL. Generalized myalgia (muscle pain) severe enough to limit normal activities. Exclusion of other neoplastic or infectious conditions that could explain the syndrome.

Question 70

How is it determined if an epidemic is occurring?

Answer 70

An epidemic is considered to be occurring if the number of cases exceeds the usual number, which can only be assessed if ongoing surveillance provides data on typical case numbers. A completely new disease or syndrome typically meets the criteria for an epidemic.

Question 71

What are the three key factors used to characterize an epidemic?

Answer 71

An epidemic is characterized by time, place, and person using the criteria in the case definition.

Question 72

Why is it important to establish a case definition before data collection in an epidemic investigation?

Answer 72

determines the data needed to classify persons as affected or unaffected, so data collection should not start until it is established.

Question 73

How is the time dimension of an epidemic described?

Answer 73

time dimension is best described by an epidemic time curve, which plots time on the x-axis and the number of new cases on the y-axis. Time units on the x-axis should be smaller than the probable incubation period.

Question 74

What questions should be considered regarding the type of exposure in an epidemic?

Answer 74

Was the exposure from a single source or spread from person to person? What was the probable route of spread (e.g., respiratory, fecal-oral, skin-to-skin, body fluids, or vectors)? When were affected persons exposed, and what was the incubation period? Were there secondary cases (person-to-person transmission)?

Question 75

Why is it important to define the location of cases in an epidemic?

Answer 75

Defining the location of cases is important because geographic clustering may provide clues about the source or spread of the disease. However, other data is often needed to complete the interpretation.

Question 76

How can a spot map help in an epidemic investigation?

Answer 76

A spot map shows where each affected person lives, works, or attends school, which can help in identifying patterns or sources of the epidemic.

Question 77

What are some important characteristics of persons affected by an epidemic? A: Important characteristics include:

Answer 77

Age, gender, race, ethnicity, and religion Source of water, milk, or food Immunization status Type of work or schooling Contacts with other affected persons

Question 78

What is the source of infection in an epidemic?

Answer 78

The source of infection refers to the person (index case) or vehicle (such as food or water) that initially introduced the infection into the affected community.

Question 79

What are the different patterns of spread in an epidemic?

Answer 79

Common-source pattern: Infection comes from a single source. Propagated pattern: Infection spreads from person to person. Mixed pattern: A combination of both common-source and propagated patterns.

Question 80

What are the modes of transmission (MOT) in an epidemic?

Answer 80

Modes of transmission include: Respiratory Fecal-oral Vector-borne Skin-to-skin contact Exchange of body fluids (e.g., serum) Contact with fomites (objects like soiled sheets or doorknobs that can carry organisms)

Question 81

What is the purpose of testing a hypothesis in an epidemic investigation?

Answer 81

Testing a hypothesis involves using statistical tests (e.g., Z-test, T-test) and laboratory studies to confirm or refute epidemiologic hypotheses, providing evidence for the source, spread, and mode of transmission of the disease.

Question 82

What are some laboratory methods used to test hypotheses in an epidemic investigation?

Answer 82

Cultures from patients and, if appropriate, from vehicles like food or water. Stool examination for ova and parasites. Serum tests for antibodies (acute and convalescent samples to check for an increase in antibodies). Tests for non-microbiological agents, such as toxins or drugs.

Question 83

Why might control measures be initiated before the source and route of spread are known in an outbreak?

Answer 83

Control measures may be initiated immediately due to public demand for action, even before the source and route of spread are confirmed. However, efforts should aim not to interfere with the ongoing investigation.

Question 84

What are some general control measures that can be taken during an outbreak?

Answer 84

Sanitation: Improving cleanliness and hygiene to prevent further spread. Prophylaxis: Administering preventive treatments or vaccines. Diagnosis and treatment: Identifying and treating affected individuals. Control of disease vectors: Reducing or eliminating the organisms (e.g., mosquitoes) that spread the disease.

Question 85

Why is follow-up surveillance important after an outbreak?

Answer 85

Follow-up surveillance is crucial to detect subsequent outbreaks and to evaluate the effectiveness of the control measures implemented during the outbreak.

Question 86

What is the difference between active and passive surveillance in post-outbreak monitoring?

Answer 86

Active surveillance is more reliable than passive surveillance because it involves actively seeking out cases and data, while passive surveillance relies on reports from healthcare providers or other sources.