The Ascertainment and Enhancement of Gastrointestinal Infection Surveillance and Statistics (AGEISS) project aims to use spatial statistical methods to identify anomalies in the space-time distribution of nonspecific, gastrointestinal infections in the United Kingdom, using the Southampton area in southern England as a test case. Health-care providers are asked to report incident cases daily. Regionwide incident data are then sent electronically to Lancaster, where a statistical analysis of the space-time distribution of incident cases is updated. The results are then posted to a Web site with tabular, graphical and map-based summaries of the analysis. Here we use the AEGISS project to discuss the methodological issues in developing a rapid-response, spatial surveillance system. We consider simple, exploratory statistical methods together with more sophisticated methods, based on hierarchical space-time stochastic process models defined either at individual or small-area levels. The chapter is a report of work in progress. Currently, the Web-based AEGISS reporting system uses only simple summaries of the incident data, but its ultimate aim is to display the results of formal predictive inference in a hierarchical model of space-time variation in disease risk.