(The order of these steps may vary)
. Define the outbreak and validate the existence of an outbreak.
- a. define the "numerator" (cases)
- -clinical features - is the disease known?
- -what are its serologic or cultural aspects?
- -are the causes partially understood?
- b. define the "denominator" (population at risk, i.e. susceptible)
- c. determine whether the observed number of cases clearly exceeds the expected number
- d. calculate the attack rates
Examine the distribution of cases by the following:
- a. Time
- b. Place
- (Look for time-place interactions)
. Look for combinations (interactions) of relevant variables
. Develop hypotheses based on the following:
- a. existing knowledge (if any) of the dz
- b. analogy to diseases of known etiology
- c. findings from investigation of the outbreak
. Test hypotheses
- a. further analyze existing data (case-control studies)
- b. refine hypotheses and collect additional data that may be needed
. Recommend control measures
- a. control of current outbreak
- b. prevention of future similar outbreaks
. Prepare a written report of the investigation and the findings
. Communicate findings to those involved in policy development and implementation AND to the public