Disease Clusters: An Overview
Answers to Pretest Questions
CE Original Date: August 1, 2002
CE Expiration Date: September 30, 2008
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|The following are answers to pretest questions.
- The term "cluster" is an unusual aggregation, real or perceived, of health events that are grouped together in time and space and that are reported to a public health unit.
- The public health department investigates disease clusters. The public health department's role in the disease cluster investigation involves the following:
- collecting accurate case information,
- conducting active surveillance through local surveys or by using health data registries,
- conducting environmental or occupational exposure assessments when warranted,
- ensuring that appropriate public and health professional communication and education is occurring specifically related to the existence of a disease cluster and any associated factors, and
- initiating timely and effective actions to mitigate factors associated with the disease cluster.
- The steps involved in a disease cluster investigation are (1) establish a case definition; (2) confirm the suspected cases; (3) define a "population denominator" measured in person-years, search for additional numerator cases within that population, and draw conclusions about the "unusualness" of the cases; (4) review the literature for risk factors and exposure hypotheses; (5) perform an exposure assessment; and (6) generate biologically plausible hypotheses.
- The physician's overall responsibility is to suspect a cluster of disease on the basis of clinical observation, complete an exposure history, confirm cases through accurate clinical and laboratory diagnosis, act as a sentinel in reporting cases to the local public health unit, and educate patients about occurrence of disease.
- The first line for contact is usually the public health department.
- Following are the most important education points:
- The current problem and the next appropriate diagnostic step.
- Specific factors related to the occurrence of the particular disease (e.g., latency period for cancer, significance of family history, and other confounding factors).
- Whether it is likely or unlikely that the patient's perceived exposure might be responsible for the problem; if it is likely, discuss your role and responsibility.