In epidemic, 1st step is?
Verification of diagnosis
Isolation
Immunization
Notification
The steps in epidemic investigation are :

Verification of diagnosis
Confirmation of the existence of epidemic
Defining the population at risk
Obtaining a map of the area
Counting the population
Rapid search for all cases & their characteristics
Medical survey
Epidemiological case sheet
Searching for more cases
Data analysis
Formulation of hypothesis
Evaluation of ecological factors
Further investigation of population at risk
Writing the report