Analysis of Epidemiological Curves: Point Source, Common Source, and Propagated Outbreak Patterns
Overview
This paper analyzes three types of epidemiological curves used to track disease outbreaks: point source outbreaks (Hepatitis A), continuous/intermittent common source outbreaks (diarrheal illness), and propagated outbreaks (measles). The author examines the characteristics of each curve type and provides recommendations for determining exposure periods and transmission patterns in epidemiological investigations.
What this coursework covers
- Introduction to epidemiological curves and their purpose in outbreak control
- Analysis of point source outbreak curve using Hepatitis A November-December 1978 data
- Examination of continuous common source outbreak curve for diarrheal illness
- Propagated outbreak analysis using measles case data with person-to-person transmission
- Recommendations for epidemiological investigation methods for each outbreak type
Preview
Description of Epidemiology Curves
Epidemiology curves show the progression of illnesses from an outbreak over a given time. The description of epidemiological curves helps measure the control of illness progress and the provision of timely information for decision-makers and other health personnel. The curve showing the cases of Hepatitis A from November- December of 1978 shows a group of people exposed to hepatitis A over a short period. This curve is grouped under point source outbreak curves since patients became ill at a single incubation period. The point-source outbreak curve usually has gradual downslope and a steep upslope (CDC, 2012).
The second curve shows an example of a continuous common source or intermittent outbreak curve showing Diarrheal illness at a given time. The length of illness exposure and the length of incubation periods have widened and flattened at the curve peaks. The last curve that shows the measles cases is a propagated outbreak, where the cases have resulted from person-to-person transmission. The cases occurred over more than one incubation period. The curve indicates that the cases had occurred 11 days apart from each other.
My recommendation of the first curve of Hepatitis A is that the maximum and minimum incubation periods should be determined first then pinpoint the likeliness of exposure through counting back from the first case to the last one. On the second curve of diarrheal illness, there should be the calculation of the minimum time people were exposed to the illness.