<prompt> First step in epidemic done by an epidemiologist?Identity the casesConfirm the diagnosisIdentify the prone peopleIdentify the causative factors  <response>: Ans. is b i.e., Confirmation of diagnosis Steps for Investigation of Epidemic : Verification of diagnosis : Is the first step in investigation of an epidemic Confirmation of existence of an epidemic: Compare with disease frequencies during same period in previous years Epidemic threshold: An arbitrary limit of 2 standard errors from the endemic occurrence Defining the population at risk: Obtaining the map of the area Calculation of appropriate denominator of population at risk Rapid search for all cases and their characteristics: Medical survey Epidemiological case sheet Searching for more cases: Search for new cases is carried out everyday, till the area is declared free of epidemic; this period is usually taken as twice the incubation period of the disease since the occurrence of last case Data analysis: Formulation of hypothesis Testing of hypothesis Evaluation of ecological factors Fuher investigation of population at risk Writing the repo 