OUTBREAK INVESTIGATION Flashcards
8 examples of LEVELS OF DISEASE
- BASELINE
- SPORADIC
- ENDEMIC
- HYPERENDEMIC
- EPIDEMIC
- OUTBREAK
- CLUSTER
- PANDEMIC
[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 maybe unknown
CLUSTER
[LEVELS OF DISEASE]
- An epidemic that has spread over several
countries or continents, usually affecting a large number of people
PANDEMIC
three TYPES OF OUTBREAK
- COMMON SOURCE
- PROPAGATED EPIDEMIC
- MIXED EPIDEMIC
[TYPES OF OUTBREAK]
- People are exposed continuously or intermittently to a harmful source
- Period of exposure maybe brief or long
- Intermittent exposure often results in an epi curve with irregular peaks that reflect the timing and the extent of exposure
COMMON SOURCE
[TYPES OF OUTBREAK]
‘COMMON SOURCE’ examples
A. COMMON POINT SOURCE
B. CONTINUOUS EXPOSURE
C. INTERMITTENT
[TYPES OF OUTBREAK]
‘COMMON SOURCE’
- Cases were all exposed to the same source during a brief period of calendar time;
- Typically shows a sharp upward slope and a gradual downward slope
- Is a common source outbreak in which the period of exposure is brief, and all cases occur within one incubation period
COMMON POINT SOURCE
[TYPES OF OUTBREAK]
‘COMMON SOURCE’
- Continuous exposure will often cause cases to rise gradually (and possibly to plateau, rather than to peak)
CONTINUOUS EXPOSURE
[TYPES OF OUTBREAK]
‘COMMON SOURCE’
- Brief, sporadic exposure period
- Irregular peaks- reflect timing and extent of exposure
- The gaps between the outbreaks might initially suggest person-to-person transmission followed by an incubation period.
INTERMITTENT
[TYPES OF OUTBREAK]
- Spread is from person-to-person
- Can last longer than source outbreaks
- Disease agent may replicate in a susceptible host as part of the transmission cycle;
- May have multiple waves
- The classic epi curve for a propagated
outbreak has progressively taller peaks, one incubation period apart
PROPAGATED EPIDEMIC
[TYPES OF OUTBREAK]
- Involve both a single, common exposure to an infectious agent and secondary propagative spread to other individuals (e.g., person to person transmission)
- Either same disease introduced separately or different diseases with different incubation periods introduced around the same time
[Examples:]
Many food borne pathogens (Salmonella, typhoid, Hepatitis A) and airborne organism (M. tuberculosis)
MIXED EPIDEMIC
[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]
‘determine the TIME FRAME’
- Acute food poisoning: Staphylococci toxins, C. perfringens
- Heavy metal exposure: cadmium, copper, zinc
- Other poisonings: MSG, mushroom, shellfish poisoning
HOURS
[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]
‘determine the TIME FRAME’
- Some food poisonings: Salmonella (1-2 ____), V. cholerae, C. jejuni
- Bacterial infections: Legionnaire’s disease, Mycoplasma pneumoniae
- Viral infections: influenza (1-3 _____), adenovirus (1-5 ____), enteroviral infections (5-6 _____)
DAYS
[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]
‘determine the TIME FRAME’
- Common childhood disease: measles, mumps, rubella (2-3 _____)
- Hepatitis A (2-6 ______)
WEEKS
[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]
‘determine the TIME FRAME’
- Hepatitis B (2-6 weeks)
- Rabies (0.5-12 _____)
MONTHS
[EXAMPLES OF EPIDEMIC ACCDG TO
INCUBATION PERIOD]
‘determine the TIME FRAME’
- Radiation induced leukemia
- Kuru (1-27 ______)
YEARS
[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]
The _______ of susceptible persons who are
_________ to a source of infectious and become
_________.
number, exposed, infected
[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]
The period of time over which __________ __________ are exposed to the ________.
susceptible persons, source
[FACTORS AFFECTING DURATION OF
AN EPIDEMIC]
The ___________ and ___________ incubation periods for the disease.
minimum, maximum
- Type of incidence rate used when the occurrence of disease among a population at risk increases greatly over a short period of time, often related to specific exposure.
- Frequently used to describe the occurrence of
foodborne illness, infectious disease, and other acute epidemics
ATTACK RATE
formula for an attack rate
attack rate = 𝑖𝑙𝑙 / 𝑖𝑙𝑙+𝑤𝑒𝑙𝑙 𝑥100
