<prompt> What is the denominator in calculation of incidence -Number of fresh casesNumber of symptomatic casesTotal number of casesPopulation at risk  <response>: Incidence is defined as new cases occurring in a defined population during a specified period of time. Incidence number of new cases of specific disease in a given time proofpopulation at risk during that period 100 refer pgno:60 park 23 rd edition 