Epidemiology module of practical skills for mbbs student

STEP 4: DESCRIBE THE OUTBREAK

Describe the outbreak in terms of time, place and person.

Time: What are the dates of onset of cases?

Plot these to prepare an Epidemic curve i.e. a graph showing cases by date of onset or by date of report (See Figure 10.4). It helps to demonstrate where and how an outbreak began, how quickly the disease is spreading, the stage of the outbreak (start, middle or ending phase), and whether control efforts are having an impact.

Place: Where do cases reside?

Prepare a Spot map (See Figure 10.2) of the area showing the location of all confirmed cases. It helps to identify areas with clusters of disease. Further investigation of these areas may reveal weaknesses in the local immunization program.

Person: Who are affected?

The Graph or table of age distribution and immunization status of cases (See Figure 10.3) are

prepared from the line list of cases. This information helps to identify the most affected age-groups and those cases which were not preventable (e.g. those developing measles before the scheduled age of immunization).