This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
Missing cases are detected by 
Select and explain. 
A. Active surveillance, B. Passive surveillance, C. Sentinel surveillance, D. Prevalence rate
C: Sentinel surveillance
Answer: C: Sentinel surveillance 
Explanation: Sentinal surveillance is a method of identifying the missing cases and thereby supplementing the notified cases. Helps to estimate disease prevalence. Repoing bias minimized. Note: India is the 1st country to have Sentinal surveillance set up for follow up of cataract surgeries. Ref: Park's Textbook of Preventive and Social Medicine; 24th edition - Page no. 45