This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
An impoant measure of the communicability of a disease is - 
Select and explain. 
A. Case fatality rate, B. Disease specific moality rate, C. Infection rate, D. Secondary attack rate
D: Secondary attack rate
Answer: D: Secondary attack rate 
Explanation: .secondary attack rate is defined as the number of exposed persons developing the disease within the range of the incubation period following exposure to a primary case.its application is limited only to infectious diseases,in which the primary case is infective,.duration of exposure is also an impoant factor in determining the extent of spread. ref:park&;s textbook,22nd edition,pg no 96