This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
First step in epidemic done by an epidemiologist? 
Select and explain. 
A. Identity the cases, B. Confirm the diagnosis, C. Identify the prone people, D. Identify the causative factors
B: Confirm the diagnosis
Answer: B: Confirm the diagnosis 
Explanation: 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