This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Indicators of Health, Subject name: Social & Preventive Medicine
Virulence of a disease is indicated by: 
Select and explain. 
A. Proportional mortality rate, B. Specific mortality rate, C. Case fatality rate, D. Amount of GDP spent on control of disease
C: Case fatality rate
Answer: C: Case fatality rate 
Explanation: Ans. (c) Case fatality rateCASE FATALITY RATE (CFR):* CFR represents 'killing power of a disease'- It is 'closely related to virulence of organism'CFR=Totalno.ofcasesduetoadiseaseTotalno.ofdeathsduetoadisease x100* CFR is a Proportion: Always expressed in percentage* CFR is the 'complement of Survival Rate', thus CFR =1 - Survival Rate* Limitations of CFR:- Time interval is not specified- Usefulness is limited for chronic diseases - CFR for the same disease may vary in different epidemics