Step 1: Recall the purpose of IDSP, which is to catch early warning signals of outbreaks. It therefore tracks epidemic-prone and programme-relevant diseases rather than every infection.
Step 2: Confirm the listed conditions. Cholera sits under water-borne disease, tuberculosis under respiratory disease, and meningococcal disease appears within the meningoencephalitis syndrome group, so all three are monitored.
Step 3: Herpes zoster is a sporadic reactivation illness with no outbreak potential and no control programme, so it falls outside IDSP, marking it the exception.
\[\boxed{\text{Herpes zoster}}\]