1. Outbreak Management

2. Learning Objectives
Describe the occurrence of disease in a population.
Discuss how an epidemic curve can help in managing an outbreak.
Outline the steps in outbreak investigation.
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3. Time involved
60 minutes
December 1, 2013

4. Purposes of Outbreak Investigation
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To Identify the causal agent
To find the source of infection by studying the occurrence of the disease among persons, place, or time, as well as determining specific attack rates
Formulate recommendations to prevent further transmission
Communicable disease outbreak investigation outlines what an epidemiologist does when investigating disease patterns. Analysis of these patterns leads to an understanding of their spread and control. Outbreaks should be identified and investigated promptly because of morbidity, cost, and institutional image.
Outbreak investigations may lead to improved patient care.
Early identification of an outbreak is also important to limit spread by healthcare workers or contaminated materials. A potential problem may be initially identified by nurses, physicians, microbiologists, or other health care workers, or through an infection surveillance program. Appropriate investigations are required to identify the source of the outbreak and justify control measures.

5. Definitions - 1 Outbreak or epidemic
An excess over the expected (usual) level of a disease within a geographic area
However, one case of an unusual disease may constitute an epidemic
E.g., postsurgical group A streptococcus infection
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When the number of reported cases is: higher than what is expected on the basis of previous reports during a non-epidemic period, for a given population, in a defined time period (i.e., historical disease patterns
From επί (epi), meaning "upon or above" and δήμος (demos), meaning "people") occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience. Epidemiologists often consider the term outbreak to be synonymous to epidemic.

6. Definitions - 2 Endemic Pandemic
The usual level of a disease within a geographic area
E.g., a hospital
These ‘sporadic’ infections represent most preventable healthcare-associated infections
Baseline incidence
Pandemic
An epidemic that spreads in several countries
Usually affecting many people
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Endemic - from Greek en- in or within + δῆμος demos people; a disease or condition regularly found among particular people or in a certain area.
Pandemic - from Greek πᾶν pan "all" + δῆμος demos "people“; is an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic.

7. Endemic and Epidemic “Endemic” “Epidemic” Number of Cases of Disease
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“Endemic”
“Epidemic”
Time
Number of Cases
of Disease
Baseline or endemic level of the disease. This level is not necessarily the desired level, which may in fact be zero, but rather is the observed level. In the absence of intervention and assuming that the level is not high enough to deplete the pool of susceptible persons, the disease may continue to occur at this level indefinitely. Thus, the baseline level is often regarded as the expected level of the disease.
While some diseases are so rare in a given population that a single case warrants an epidemiologic investigation (e.g., rabies, plague, polio), other diseases occur more commonly so that only deviations from the norm warrant investigation (as in the graph). Sporadic refers to a disease that occurs infrequently and irregularly.

8. Healthcare-associated infections
Majority of healthcare-associated infections are endemic
Outbreak of healthcare-associated infections occur typically in a specific group of patients
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Specific groups may be a certain intensive care unit, patients receiving dialysis, etc.
Epidemics/outbreaks occur when an agent and susceptible hosts are present in adequate numbers, and the agent can be effectively conveyed from a source to the susceptible hosts. More specifically, an epidemic may result from:
A recent increase in amount or virulence of the agent,
The recent introduction of the agent into a setting where it has not been before,
An enhanced mode of transmission so that more susceptible persons are exposed,
A change in the susceptibility of the host response to the agent, and/or
Factors that increase host exposure or involve introduction through new portals of entry.

9. Definitions - 3 Relative risk
A measure of association between a disease or condition and a factor under study
Calculation
Divide the incidence rate of those exposed to the factor by the incidence rate of those not exposed
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A comparison of the risk of a particular event for different groups of people. Relative risk (RR) is the risk of an event (or of developing a disease) related to exposure. Relative risk is a ratio of the probability of the event occurring in the exposed group versus a non-exposed group

10. Interpretation of Relative Risk
RR =1
Incidence in the exposed group is the same as in the non-exposed
There is no association between exposure and disease
RR >1
Denotes a larger incidence in the exposed than in the non-exposed
Exposure seems to increase the probability of developing the disease
RR <1
Denotes a smaller incidence in the exposed than in the non-exposed
Exposure seems to decrease the probability of developing the disease
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Whether a given relative risk can be considered statistically significant is dependent on the relative difference between the conditions compared, the amount of measurement and the noise associated with the measurement (of the events considered). In other words, the confidence one has, in a given relative risk being non-random (i.e. it is not a consequence of chance), depends on the signal-to-noise ratio and the sample size.

11. Types of Outbreaks Community-acquired Healthcare-associated
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Community-acquired
Food-borne infections, measles
Healthcare-associated
When two or more cases of infection appear to be epidemiologically related

12. Steps of Outbreak Investigation
Verify existence of the outbreak
Determine if there were changes in case finding or diagnostics
Establish diagnosis of reported cases
Case finding
Characterise cases
Formulate hypothesis
Test the hypothesis
Institute control measures and follow up
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The Infection Control Committee should take these steps to investigate a suspected outbreak of a communicable disease. These steps provide a guideline and may not proceed in sequence.
The steps are presented here in conceptual order. In practice, however, several may be done at the same time, or they may be done in a different order.

13. Verify existence of an outbreak
Compare the number of current cases with the usual baseline incidence
from previous months or years
If local data are not available, compare to information from national surveillance systems or the literature
these data may not be applicable to the local situation
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Some investigations will turn out to be true outbreaks with a common cause, some will be unrelated cases of the same disease, and others will turn out to be unrelated cases of similar but unrelated diseases. Before you can decide whether an outbreak exists (i.e., whether the observed number of cases exceeds the expected number), you must first determine the expected number of cases for the area in the given time frame.
Compare the number of current cases with the usual baseline incidence (from previous months or years). If local data are not available, compare to information from national surveillance systems or the literature (however, these data may not be applicable to the local situation).
Whether or not you should investigate an apparent problem further is not strictly tied to your verifying that an epidemic exists (that is, that the observed number is greater than the number expected). Other factors may come into play, including, for example, the severity of the illness, the potential for spread, political considerations, public relations, and the availability of resources.

14. Determine if there were changes in case finding or diagnostics
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New techniques or laboratory tests may increase identification when historically cases would not have been identified
Provides a new ‘baseline’ of disease
In addition to verifying the existence of an outbreak early in the investigation, you must also identify as accurately as possible the specific nature of the disease. Your goals in verifying the diagnosis are two-fold. First, you must ensure that the problem has been properly diagnosed—that it really is what it has been reported to be. Second, for outbreaks involving infectious agents, you must to be certain that the increase in diagnosed cases is not the result of a change in the laboratory.

15. Define cases Typically involves identifying an agent
Define cases based on the following common factors:
Population risk factors
Age, race, sex, socioeconomic status
Clinical data
Onset of signs and symptoms
Frequency and duration of clinical features associated with the outbreak
Laboratory results
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Verifying the diagnosis requires that you review the clinical findings (the symptoms and features of illness) and laboratory results for the people who are affected. If you are at all uncertain about the laboratory findings (e.g., if they are inconsistent with the clinical findings), you should have a laboratory technician review the techniques being used. If you expect a need for specialized laboratory work (e.g., special culturing or DNA analysis), you should begin obtaining the appropriate specimens, isolates, and other laboratory material from a sufficient number of patients as soon as possible.
Define cases based on the following common factors:
Population risk factors: e.g., age, race, sex, socioeconomic status.
Clinical data: e.g., onset of signs and symptoms, frequency and duration of clinical features associated with the outbreak, treatments, and devices.
Laboratory results.

16. Case Definition
The inclusion and exclusion criteria for cases must be precisely identified
The definition should differentiate between infection and colonisation
Includes a unit of time and place and specific biological and/or clinical criteria
A graded definition (definite, probable, or possible) often helps
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A case definition is a standard set of criteria for deciding whether, in this investigation, a person should be classified as having the disease or health condition under study.
A case definition should be developed; it must include a unit of time and place and specific biological and/or clinical criteria. The inclusion and exclusion criteria for cases must be precisely identified. A graded definition (definite, probable, or possible) often helps. To be classified as confirmed, a case usually must have laboratory verification. A case classified as probable usually has the typical clinical features of the disease without laboratory confirmation. A possible case usually has fewer of the typical clinical features. The definition should differentiate between infection and colonisation.
A case definition usually includes four components:
clinical information about the disease, 
characteristics about the people who are affected, 
information about the location or place, and 
a specification of time during which the outbreak occurred.
Example of case definition: A definite case patient will be defined as a patient hospitalised in the geriatric ward during January, with diarrhoea, cramps, and vomiting and in whom routine culture of faeces identifies Salmonella species.

17. Case Finding Collect critical data and specimen information from:
Laboratory reports
Medical records
Patient charts
Physicians and nursing staff
Public health data
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Search for other cases that may have occurred retrospectively or concurrently. Collect critical data and specimen information from:
Laboratory reports
Medical records
Patient charts
Physicians and nursing staff
Public health data
You should collect the following types of information about every person affected:
Identifying information: This may include name, address, and telephone number and allows you and other investigators to contact patients for additional questions and to notify them of laboratory results and the outcome of the investigation. Addresses also allow you to map the geographic extent of the problem.
Demographic information: This may include age, sex, race, and occupation and provides the details that you need to characterize the population at risk.
Clinical information: This information allows you to verify that the case definition has been met. Date of onset allows you to create a graph of the outbreak. Supplementary clinical information may include whether the person was hospitalized or died and will help you describe the spectrum of illness.
Risk factor information: Information about risk factors will allow you to tailor your investigation to the specific disease in question. For example, in an investigation of hepatitis A, you would look at exposure to food and water sources.

18. Characterise cases
Assemble and organise available information for analysis
From this information, the population at risk can be accurately described
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Once you have collected some data, you can begin to characterize an outbreak by time, place, and person. In fact, you may perform this step several times during the course of an outbreak. Characterizing an outbreak by these variables is called descriptive epidemiology, because you describe what has occurred in the population under study. This step is critical for several reasons. First, by becoming familiar with the data, you can learn what information is reliable and informative (e.g., the same unusual exposure reported by many of the people affected) and what may not be as reliable (e.g., many missing or "don't know" responses to a particular question). Second, you provide a comprehensive description of an outbreak by showing its trend over time, its geographic extent (place), and the populations (people) affected by the disease. This description lets you begin to assess the outbreak in light of what is known about the disease (e.g., the usual source, mode of transmission, risk factors, and populations affected) and to develop causal hypotheses.

19. Characterise cases - Time
The exact period of the outbreak
The probable period of exposure
Date of onset of illness for cases; draw an epidemic curve
Is the outbreak common source or propagated?
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Traditionally, we show the time course of an epidemic by drawing a graph of the number of cases by their date of onset. This graph, called an epidemic curve, or "epi curve" for short, gives a simple visual display of the outbreak's magnitude and time trend.

20. Characterise cases – Place/Time
Service, ward, operating room
Clustering of cases
Person
Patient characteristics (age, sex, underlying disease)
Possible exposures (surgery, nursing and medical staff , infected patients)
Therapy (invasive procedures, medications, antibiotics)
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Assessment of an outbreak by place provides information on the geographic extent of a problem and may also show clusters or patterns that provide clues to the identity and origins of the problem. A simple and useful technique for looking at geographic patterns is to plot, on a "spot map" of the area, where the affected people live, work, or may have been exposed.
You determine what populations are at risk for the disease by characterizing an outbreak by person. We usually define such populations by personal characteristics (e.g., age, race, sex, or medical status) or by exposures (e.g., occupation, leisure activities, use of medications, tobacco, drugs). These factors are important because they may be related to susceptibility to the disease and to opportunities for exposure.
After characterizing an outbreak by time, place, and person, you need to summarize what you know to see whether your initial hypotheses are on track. You may find that you need to develop new hypotheses to explain the outbreak. From all this information, the population at risk can be accurately described.

21. Calculate rates Incidence rate Attack rate
The number of new cases occurring in the population during a specified time / number of persons exposed to the risk of developing the disease during that time
Attack rate
The cumulative incidence rate of infection in a group over a period of an epidemic
Number of people at risk who are infected / Total number of people at risk
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Incidence refers to the occurrence of new cases of disease or injury in a population over a specified period of time. The numerator is the number of new cases identified during the period of observation. The denominator is the sum of the time each person was observed, totaled for all persons. This denominator represents the total time the population was at risk of and being watched for disease. Thus, the incidence rate is the ratio of the number of cases to the total time the population is at risk of disease.
Attack rate – also called incidence proportion - the proportion of an initially disease-free population that develops disease during a specified (usually limited) period of time. Synonyms include probability of getting disease and cumulative incidence. Incidence proportion is a proportion because the persons in the numerator, those who develop disease, are all included in the denominator (the entire population). As a measure of incidence, it includes only new cases of disease in the numerator. The denominator is the number of persons in the population at the start of the observation period.

22. Source of Infection Common source (single-point source)
Same origin
Propagated or continuing source (on-going transmission)
Infections are transmitted from person to person
Both common and propagated source
Intermittent exposure to a common source
Produces an epidemic curve with irregularly spaced peaks
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The source of infection may be:
1. Common source (single–point source): Same origin (i.e., the same person or vehicle is identified as the primary reservoir or means of transmission).
2. Propagated or continuing source (ongoing transmission): Infections are transmitted from person to person in such a way that cases identified cannot be attributed to agent(s) transmitted from a single source.
3. Both common and propagated source (intermittent source): Intermittent exposure to a common source produces an epidemic curve with irregularly spaced peaks.

23. Epidemic curve - 1 Also called a histogram
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Also called a histogram
Determines the character of an epidemic
Cases are plotted by date of onset of illness
Time intervals (on the X axis) are based on the incubation or latency period of the disease and the length of the period over which cases are distributed
The character of an epidemic is determined by an epidemic curve. This is a graph in which cases are plotted according to the time of onset of illness.

24. Epidemic curve - 2
The reasons for constructing an epidemic curve include:
To determine whether the source of infection was common, propagated, or both
To identify the probable time of exposure of the cases to the source(s) of infection
To identify the probable incubation period
To determine if the problem is ongoing
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The reasons for constructing an epidemic curve include:
To determine whether the source of infection was common, propagated, or both; the shape of the curve is determined by the epidemic pattern.
To identify the probable time of exposure of the cases to the source(s) of infection.
To identify the probable incubation period.
To determine if the problem is ongoing.
An epidemic curve provides a great deal of information. First, you will usually be able to tell where you are in the course of the epidemic, and possibly to project its future course. Second, if you have identified the disease and know its usual incubation period, you may be able to estimate a probable time period of exposure. Finally, you may be able to draw inferences about the epidemic pattern—for example, whether it is an outbreak resulting from a common source exposure, from person-to-person spread, or both.

25. Draw epidemic curve and calculate by either of the following methods
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To draw an epidemic curve, you first must know the time of onset of illness for each person. For most diseases, date of onset is sufficient; however, for a disease with a very short incubation period, hours of onset may be more suitable. The number of cases is plotted on the y-axis of an epi curve; the unit of time, on the x-axis. We usually base the units of time on the incubation period of the disease (if known) and the length of time over which cases are distributed. As a rule of thumb, select a unit that is one-fourth to one-third as long as the incubation period.
Draw epidemic curve and calculate by either of the following methods
Using the mean or median incubation period: identify the peak of the epidemic or the date of onset of the median case; count back into one incubation period
Using minimum and maximum incubation periods: start with the first case identified and count back in time the minimum incubation period; then using the last case, count back in time the maximum incubation period.
A . Propagated source: single exposure, no secondary cases (e.g., measles).
B. Propagated source: secondary and tertiary cases (e.g., hepatitis A).
Common source: point exposure .
Common source: Intermittent exposure.

26. Epidemic curve Helps to develop hypotheses Incubation period
Etiological agent
Type of source
Mode of transmission
Propagated source
Common source
Time of exposure
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In practice, other information gathered in the course of investigation is used to interpret epidemic curves. Information required includes the specific disease involved, either mean or median, or minimum and maximum, incubation period(s) for the specific disease, and dates of onset of cases.
The first step in interpreting an epidemic curve is to consider its overall shape, which will be determined by the pattern of the epidemic (e.g., whether it has a common source or person-to-person transmission), the period of time over which susceptible people are exposed, and the minimum, average, and maximum incubation periods for the disease.

27. Common Source Outbreak
Example: the first outbreak of Legionnaires’ disease
An epidemic curve with a steep up slope and a gradual down slope indicates a single source (or "point source") epidemic in which people are exposed to the same source over a relatively brief period. In fact, any sudden rise in the number of cases suggests sudden exposure to a common source. In a point source epidemic, all the cases occur within one incubation period. If the duration of exposure is prolonged, the epidemic is called a "continuous common source epidemic," and the epidemic curve will have a plateau instead of a peak. Person-to-person spread (a "propagated" epidemic) should have a series of progressively taller peaks one incubation period apart.
Curve approximates to a normal distribution curve if there are enough cases and if they are limited to a short exposure with maximum incubation of a few days (common source).
Exposure may be continuous or intermittent; intermittent exposure to a common source produces a curve with irregularly spaced peaks.
Determination of the probable period of exposure of cases in a common-source outbreak.
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28. An explosive epidemic of short duration generally indicates
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A common source of infection
Exposure over a short period of time
A large numbers of susceptible exposed
A high attack rate
An incubation period with little variation
In a point-source epidemic of a known disease with a known incubation period, you can use the epidemic curve to identify a likely period of exposure. This is critical to asking the right questions to identify the source of the epidemic.

29. Propagated Source Outbreak
Cases occur over a long period
Explosive epidemics due to person-to-person transmission may occur
E.g., chickenpox
If secondary and tertiary cases occur, intervals between peaks usually approximate to the average incubation period
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Cases occur over a long period.
Explosive epidemics due to person-to-person transmission may occur (i.e., chickenpox).
If secondary and tertiary cases occur, intervals between peaks usually approximate to the average incubation period.

30. no secondary cases (e.g. measles)
Propagated source - 1
Single exposure,
no secondary cases (e.g. measles)
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31. Secondary and tertiary cases
Propagated source - 2
Secondary and tertiary cases
(e.g., hepatitis A)
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32. Determine Exposure Period
Using the mean or median incubation period
Identify the peak of the epidemic or the date of onset of the median case
Count back into one incubation period
Using minimum and maximum incubation periods
Start with the first case identified and count back in time the minimum incubation period
Then using the last case, count back in time the maximum incubation period
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The range of dates identified represent the most likely period of exposure and ideally should fall within a few days of each other. If the three dates are widely separated, this indicates that the incubation period has a wide range or the outbreak is not a point source outbreak.

33. Exposure Period December 1, 2013
To determine the most likely period of exposure for an outbreak, you need to know the average incubation period for the disease and the range of incubation periods, which are the minimum and maximum reported incubation periods. The incubation period is the time from exposure to the causative agent until the first symptoms develop and is characteristic for each disease agent.
Step 1: Identify the Peak of the outbreak = Identify the peak of the outbreak. In the outbreak below, the peak occurs on 10 December, which is the date with the highest number of cases.
Step 2: Count Back the Average Incubation Period = The average incubation period for Shiga toxin-producing E. coli (STEC) is 4 days. Now, count back 4 days from the peak. That date is 6 December.
Step 3: Count Back the Minimum Incubation Period = Identify the last case and count back the maximum incubation period. In this case, the last case is 13 December, and the incubation period is 10 days. You should count back to 3 December.
Step 4: Count Back the Maximum Incubation Period = Identify the last case and count back the maximum incubation period. In this case, the last case is 13 December, and the incubation period is 10 days. You should count back to 3 December.
Result: Most Likely Period of Exposure
After analyzing the epi curve, we determined the first case occurred on December 9, the peak of the outbreak on December 10, and the last case occurred on December 13. With the described methods, we have determined the Average incubation period from peak — December 6
Minimum incubation period from the first case — December 7
Maximum incubation period from the last case — December 3
Using these range of dates, we have can determine the most likely period of exposure for this outbreak is December 3-7. Investigators will focus on this time period when searching for the exposure that resulted in this outbreak.

34. Formulate hypothesis Make a best guess to explain the observations
The hypothesis should explain most cases
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The hypotheses should address the source of the agent, the mode (vehicle or vector) of transmission, and the exposures that caused the disease. Also, the hypotheses should be proposed in a way that can be tested.
You can develop hypotheses in a variety of ways. First, consider what you know about the disease itself: What is the agent's usual reservoir? How is it usually transmitted? What vehicles are commonly implicated? What are the known risk factors? In other words, simply by becoming familiar with the disease, you can, at the very least, "round up the usual suspects."

35. Test the Hypothesis Many investigations do not reach this stage
Investigation may end with descriptive epidemiology and then the problem goes away without intervention or does not require a special study
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This may require a special study.
Many investigations do not reach this stage; investigation may end with descriptive epidemiology and then the problem goes away without intervention or does not require a special study. Whether or not an investigation is carried out, the hypothesis testing phase is a function of available personnel, severity of the problem, and resource allocation.
2. Examples of situations that should be studied:
Infection associated with a commercial product.
Infection associated with considerable morbidity (e.g., bacteraemia) and/or mortality.
Infections associated with multiple services. For example: during an outbreak of food poisoning the rate of disease in young adults was 40% and in older individuals was 2%. It was 65% for those who ate in a popular cafeteria and only 3% for those who ate in other places. Therefore younger individuals eating in the popular cafeteria are the ones who should be investigated regarding specific foods eaten.
3. Analyse data derived from case investigation. Determine sources of transmission and risk factors associated with disease.
4. Refine hypothesis and carry out additional studies if necessary.

36. Institute Control Measures
Control measures are determined by the results of the initial analysis in consultation with appropriate professionals
They will vary depending on the agent, the mode of transmission, and observations
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Even though implementing control and prevention measures is listed as a later step, in a real investigation you should do this as soon as possible. Control measures, which can be implemented early if you know the source of an outbreak, should be aimed at specific links in the chain of infection, the agent, the source, or the reservoir.
For example, an outbreak might be controlled by destroying contaminated foods, sterilizing contaminated water, or requiring an infectious food handler to stay away from work until he or she is well.
In other situations, you might direct control measures at interrupting transmission or exposure. For example, to limit the airborne spread of an infectious agent among residents of a nursing home, you could use the method of "cohorting" by putting infected people together in a separate area to prevent exposure to others.
The aims are: 1) To control the current outbreak by interrupting the chain of transmission. 2) To prevent similar outbreaks.
Control measures are determined by the results of the initial analysis in consultation with appropriate professionals (i.e., infection prevention and control staff, epidemiologist, clinicians, microbiologists, nurses, and technicians). They will vary depending on the agent, the mode of transmission, and observations

37. Control Measures
Interventions commonly used to control an outbreak are as follows:
Control the source of the pathogen
Remove the source of contamination, e.g., discard contaminated food
Remove persons from exposure
Keep people from being exposed to mosquito bites to prevent encephalitis
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Other measures:
Inactivate or neutralise pathogen, e.g., disinfect and filter contaminated water.
Treat infected persons.
Interrupt transmission.
Control or modify the host response to exposure. Immunise susceptible hosts, use prophylactic chemotherapy, modify behaviour, or use a barrier.

38. Healthcare-Associated Infections – Control Measures
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Type of transmission suspected
Suggested action
Contact- Cross-transmission (transmission between individuals)
Patient isolation and barrier precautions determined by infectious agent(s)
Contact- Hand transmission
Improvements in hand hygiene (e.g., washing, disinfection, glove use)
Airborne agent
Patient isolation with appropriate ventilation
Waterborne agent
Checking of water supply and all liquid containers
Use of disposable devices
Foodborne agent
Elimination of the at-risk food

39. Evaluate Efficacy of Control Measures
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Cases cease to occur or return to endemic level
No change (re-evaluate cases)
Use the opportunity of an outbreak to review and correct other health care practices which could contribute to future outbreaks

40. Communicate and Write a Final Report
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During the investigation, up-to-date information is communicated to administration and appropriate authorities
A final report should be prepared describing the outbreak, interventions, and effectiveness, and summarising the contribution of each team member participating in the investigation
It should include recommendations to prevent any future occurrence
During the investigation of an outbreak, timely, up-to-date information must be communicated to administration and public health authorities. In some cases, information may be provided to the public and the media with agreement of the outbreak team, administration, and local authorities.
A final report should be prepared describing the outbreak, interventions, and effectiveness, and summarising the contribution of each team member participating in the investigation. It should include recommendations to prevent any future occurrence.

41. Summary
Outbreaks of infection should be clearly defined, identified, and promptly investigated because of their importance in terms of morbidity, cost, improvement of patient care, and institutional image
Proper steps and effective techniques should be used to investigate a suspected outbreak
Clear recommendations should be formulated to prevent further transmission and/or outbreaks
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42. References
Flora IH, Manuel B. Disease Outbreak Investigation. The Young Epidemiology Scholars Program (YES) supported by The Robert Wood Johnson Foundation and administered by the College Board,
Reingold AL. Outbreak Investigations—A Perspective. National Center for Infectious Diseases, Centers for Disease Control and Prevention. Emerg Infect Diseases 1998; 4 (1).
Susan P. Outbreak Investigation. The University of Texas, Harris county psychiatric center,
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43. Web Resource How to Investigate an Outbreak
Communicable Disease Control: Outbreak Investigation
Epidemiological Investigation of Outbreaks
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A web-based database for nosocomial outbreaks is under development -

44. Quiz Outbreak investigations are performed primarily to:
Gather clinical information about a disease
Find the source of infections
Make sure patients are treated
All of the above
Epidemic curves help determine if the problem is on-going. T/F
Control measures for healthcare-associated infections include all except:
Patient isolation
Use of disposables
Hand hygiene
Immunisation
December 1, 2013 B
True D

45. International Federation of Infection Control
IFIC’s mission is to facilitate international networking in order to improve the prevention and control of healthcare associated infections worldwide. It is an umbrella organisation of societies and associations of healthcare professionals in infection control and related fields across the globe .
The goal of IFIC is to minimise the risk of infection within healthcare settings through development of a network of infection control organisations for communication, consensus building, education and sharing expertise.
For more information go to
December 1, 2013