Inserm has developed, since 1984, an information system based on a computer network of physicians in France. It allows for constitution of large databases on diseases, with individual description of cases, and to explore some aspects of the mathematical theory of communicable diseases. We developed user-friendly interfaces for remote data entry and GIS tools providing real-time atlas of the epidemiologic situation in any location. The continuous and ongoing surveillance network is constituted of about 1200 sentinel voluntary and unpaid investigators. We studied their motivation, reasons for either withdrawal or compliance using survival analyses. We implemented early warning systems for outbreak detection and for time-space forecasting. We conducted epidemiological surveys for investigating outbreaks. Large available time and space series allowed us to calibrate and explore synchronism of influenza epidemics, to test the assumption of panmixing in susceptibles-infectious-removed type models and to study the r