<prompt> Under which level of prevention should sentinel surveillance be categorisedPrimordial preventionPrimary preventionSecondary preventionTeiary prevention  <response>: Sentinel surveillance is a method for identifying the missing cases and thereby supplementing the notified cases. it estimates disease prevalence in the total population. Repoing biases are minimised. It detects missing cases; so it comes under secondary prevention. Ref : Park;s Textbook of Preventive and Social Medicine; 23rd edition - Pgno 40 