Outbreak Investigation and Prevention & Control Flashcards
Week 9: Epidemiology
Levels of disease:
The amount of a disease that is usually present in a community; the observed but not necessarily the desired level; regarded as the expected level of disease
Baseline
Levels of disease:
A disease that occurs infrequently and irregularly
Sporadic
Levels of disease:
The constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area
Endemic
Levels of disease:
The persistently high levels of disease occurrence
Hyperendemic
Levels of disease:
An increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area
Epidemic
Levels of disease:
Similar to an epidemic but is often used for a more limited geographic area
Outbreak
Levels of disease: An aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may be unknown
Cluster
Levels of disease:
An epidemic that has spread over several countries or continents, usually affecting a large number of people.
Pandemic
Aims of outbreak investigation:
- To determine the cause of the outbreak (the disease detected)
- To prevent further spread of the outbreak (the fire fighter)
- To educate responsible individuals in the prevention of similar
outbreak in the future (the public health educator)
- To determine the cause of the outbreak
(the disease detected)
- To prevent further spread of the outbreak
(the fire fighter)
To educate responsible individuals in the prevention of similar outbreaks in the future
(the public health educator)
5 REASONS FOR INVESTIGATING OUTBREAKS
- Prevention and Control
- Gain additional knowledge/ research
- Training
- Public, political, or legal concerns
- Program considerations
- Prevention and Control
1.1 Primary Public Health reason for investigation
1.2 Principal considerations
-What is the stage of the epidemic?
-Are cases occurring in increasing numbers?
-Is the outbreak just about over?
- Prevention and Control:
What is the goal if cases are CONTINUING TO OCCUR:
To prevent occurrence of additional
cases
- Prevention and Control :
What is the goal if cases are CONTINUING TO OCCUR:
To assess the extent of the outbreak, the size, and characteristics of the
population at risk
- Prevention and Control:
What is the goal If an outbreak appears to be ALMOST OVER:
To prevent similar outbreaks in the future
- Prevention and Control:
What is the goal If an outbreak appears to be ALMOST OVER:
To identify factors which contributed to the outbreak in order to design and implement measures that would prevent similar outbreaks in the future
- Prevention and Control
1.3 How much is known about the ____________, the source, and the mode of transmission of the agent?
causative agent
1.4 The decisions regarding whether and how extensively to investigate an outbreak are influenced
by ________________.
the characteristics of the problem itself
- Gain additional knowledge/ research
- Each outbreak is __________ the natural history of the disease in question.
an opportunity to study
- Gain additional knowledge/ research
- For a newly recognized disease, ____________ provides an opportunity to define the natural history –agent, mode of transmission, and incubation period, and the clinical spectrum of the disease
field investigation
For a newly recognized disease, field investigation provides an opportunity to define the natural history – _____________.
- agent,
- mode of transmission
- incubation period,
- clinical spectrum of the disease
Are able to characterize the populations at greater risk:
identify specific risk factors (ex. Legionnaires disease in
Philadelphia in 1976; Toxic Shock Syndrome in 1980, AIDS
in early 1980’s, Eosinophilia-myalgia-syndrome in 1989)
- Gain additional knowledge/ research
Assessing the impact of control measures
- Gain additional knowledge/ research
Investigating an outbreak requires a combination of diplomacy, logical thinking, problem-solving ability,
quantitative skills, epidemiologic know-how, and judgment.
- Training
These skills improve with practice and experience
- Training
The investigating team can be composed of a seasoned
epidemiologist with trainee/s.
- Training
These concerns sometimes override scientific concerns in the decision to conduct the investigation.
- Public, political, or legal concerns
Increasingly, the public has taken an interest in ‘disease clusters’ and potential environmental exposures, and has called upon the health department to investigate
- Public, political, or legal concerns
- An outbreak of a disease (which is targeted by the public health program) may reveal a weakness in that program and provide an opportunity to modify/strengthen the program’s efforts.
- Program considerations
- Investigating the causes of an outbreak may identify populations that may have been overlooked, failures in the investigation strategy, changes in the agent, or events beyond the scope of the program
- Program considerations
8 STEPS IN AN OUTBREAK INVESTIGATION
1 * Verify the diagnosis and confirm the outbreak
2 * Define a case and conduct case finding
3 * Tabulate and orient data: time, place, person
4 * Do immediate control measures
5 * Formulate and test hypothesis
6 * Plan and execute additional studies
7 * Implement and evaluate control measures
8 * Communicate findings
PREPARATION FOR FIELD-WORK
- Investigation
- Administration
- Consultation
Appropriate scientific knowledge, supplies, and equipment; consult regarding epidemic, laboratory
specimen collection, storage, and transport
INVESTIGATION
Travel arrangements and travel orders
ADMINISTRATION
Specific roles and responsibilities
CONSULTATION