In this course, we have often assumed that investigators have knowledge of a potentially harmful exposure coincidentally with or prior to observing the disease or illness. In other situations, the first indication of a harmful exposure is a report of a potential outbreak of disease or illness. Increased numbers of cases of disease or illness may necessitate an outbreak investigation. Questions to be answered in an outbreak investigation include the following:
- Are there an unusual number of adverse health outcomes in this community?
- If so, how many? Is the number increasing, decreasing or stable?
- What type of exposure may have caused the increase?
- What is the anticipated future course and spread of this outbreak?
Basic case-control studies are very useful when investigating an outbreak of disease. Last week we studied the basic case-control study. This week we will see some more advanced case-control designs, but these are rarely used in outbreak investigations because they take longer to implement and are more complex.
Let's get started!
- Use common terms in outbreak investigation appropriately
- Develop an outbreak investigation plan
- Describe a potential outbreak with regard to person, place and time.
- Construct and interpret an epi-curve to describe the course of an outbreak
- Differentiate between a nested case-control study, a case-cohort design and a case-crossover design