Step 1: The IDSP, launched in November 2004, places a defined set of core conditions under regular surveillance, including malaria, acute diarrhoeal disease (cholera), typhoid, tuberculosis, measles, and polio, plus syndromes such as meningoencephalitis.
Step 2: Tuberculosis (option b) is the respiratory disease under surveillance, cholera (option d) is the water-borne disease, and meningococcal meningoencephalitis (option a) is captured among the unusual clinical syndromes. All three are covered.
Step 3: Herpes zoster is a self-limiting reactivation of varicella and is not an epidemic-prone or outbreak condition, so it is not part of IDSP surveillance. Hence the answer is option c.