OUTBREAK INVESTIGATION Flashcards
Levels of Diseases:
The amount of a disease that is usually present in a community
Observed but not necessarily the desired level
Regarded as the expected level of disease
Baseline
Levels of Diseases:
A disease that occurs infrequently and irregularly
Occurs occasionally at irregular intervals
Sporadic
Levels of Diseases:
The constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area
Has a stable pattern of disease occurrence in a population
Constant presence of cases in a certain population
Endemic
Levels of Diseases:
The persistently high levels of disease occurrence
Has a stable (relatively high) pattern of disease occurrence in a population
Hyperendemic
Levels of Diseases:
An increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area
From endemic to epidemic
Sudden raise in the number of cases
Epidemic
Levels of Diseases:
Similar to an epidemic but is often used for a more limited geographic area
Sudden increase in the number of cases which is more than what is usually expected in the population
Outbreak
Levels of Diseases:
An aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number maybe unknown
Cluster
Levels of Diseases:
An epidemic that has spread over several countries or continents, usually affecting a large number of people
Pandemic
ODD MAN OUT:
Epidemic: Occurrence of disease cases or deaths
- Limited to specified group of individuals during a short period of time
- Constant number of expected cases at a specified place and time
- Clearly on excess of normal expectancy (Last, 1988)
- Take note of the group; gathered together in a certain place or time
- Cases or deaths are more than what is expected at a given time and place
- Constant number of expected cases at a specified place and time
A if only the first statement is true
B if only the second statement is true
C if both of the statements are true
D if neither of the statements is true
How do epidemics occur?
- Agents and hosts are present in adequate number
- Agent can not be effectively conveyed from source to host
A
ODD MAN OUT:
Factors which may trigger an epidemic:
- Recent increase in virulence of agent (Virulence: whether the agent causes severe disease)
- Recent introduction of agent into a setting
- Persistent health education programs in communities
- Enhanced mode of transmission: important
If fast transmission: fast occurrence - Change in susceptibility of the host response to agent (Susceptibility: lack of ability to resist some extraneous agent)
- Factors that increase host exposure
- Introduction of agent through new portals of entry
- Persistent health education programs in communities
Goals of an outbreak investigation:
_____: Guide —> intervention: guide the public health for the intervention that we want to implement
_____: Identify —> source: identify the source of illness or mode of transmission
Long term goal
Short term goal
Ways on how outbreaks come to the attention of public health agencies:
A. _______
Organization or structures
Collection, analysis & interpretation of outcome-specific data
Planning, implementing & evaluation of PH practices
B. _______
A. Epidemiologic Surveillance System
Organization or structures
Collection, analysis & interpretation of outcome-specific data
Planning, implementing & evaluation of PH practices
B. Direct notification
Reasons for Investigating Outbreaks:
Primary Public Health reason for investigation
Principal considerations:
What is the stage of the epidemic? Are cases occurring in increasing numbers? Is the outbreak just about over?
Important for it will help you in needs assessment or what are the steps that are needed to further do based on the stage of the epidemic
Prevention and Control
How much is known about the causative agent, the source, and the mode of transmission of the agent? To be able to stop the outbreak
The decisions regarding whether and how extensively to investigate an outbreak are influenced by the characteristics of the problem itself
Ex: the severity of the illness, the source or mode of transmission, the availability of prevention and control measures
Reasons for Investigating Outbreaks:
If cases are Continuing to occur:
Goal: prevent occurrence of additional cases
Objective: to assess the extent of the outbreak, the size, and characteristics of the population at risk
Important in deciding and implementing the appropriate control measures
Prevention and Control
Outbreak appears to be Almost over:
Goal: prevent similar outbreaks in the future
Objective: to identify factors which contributed to the outbreak
In order to design and implement measures that would prevent similar outbreaks in the near future
Reasons for Investigating Outbreaks:
Each outbreak is an opportunity to study the natural history of the disease in question
For a newly recognized disease, field investigation provides an opportunity to define the natural history – agent, mode of transmission, and the incubation period and the clinical spectrum of the disease.
Gain additional knowledge or research
Are able to characterize the populations at greater risk: identify specific risk factors
Assessing impact of control measures
Ex: Legionnaires disease in Philadelphia in 1976; Toxic Shock Syndrome in 1980, AIDS in early 1980’s, Eosinophilia-myalgia-syndrome in 1989)