<prompt> Denominator in case fatality rateMid year populationPopulation at riskNumber of casesNumber of deaths  <response>: Case fatality rate Total number of deaths due to a paicular disease ___ X 100 Total number of cases due to to the same disease Case fatality rate represents the killing power of a disease It is simply the ratio of deaths to cases The time interval is not specified Case fatality rate is typically used in acute infectious diseases eg: food poisoning, cholera, measles Case fatality is closely related to virulence. The case fatality rate for the same disease may vary in different epidemics because of changes in the agent, host and environmental factors Reference: Park;s textbook of Preventive and Social medicine, 23rd edition, Paeg no. 58 