Surveillance has been defined as the continuing scrutiny of all aspects of the occurrence and spread of a disease that are pertinent to effective control. It involves a systematic collection, collation and analysis of data and the prompt dissemination of the resulting information to those who need to know so that action can result (Figure 30a).

Although this chapter focuses on the surveillance of communicable diseases, the principles apply similarly to non-communicable diseases including cancers.

In the United Kingdom, there is a statutory requirement for certain infectious diseases to be notified by registered medical practitioners to public authorities. This originally dates from the late nineteenth century, but the legislation has been revised recently to provide public authorities with new powers and duties to prevent and control risks to human health. In addition to the list of infectious diseases, the new regulations require clinicians to notify public health authorities of cases of other infections or contamination (including chemical or radiation) that could potentially be a significant risk to human health.