Declaration network: at the end of medical consultation, each medical staff member declares clinic signs of his patient using a numeric standardized form on computers (specific declaration software). They transmit this anonymous form to a data base located in a Military Surveillance Disease Centre in France. Analysis network: observed data are automatically compared with historical data every 10 minutes, using current past graph method (specific analysis software), to produce alarm signals. These signals have to be analysed by epidemiologists to confirm or not the real alert about outbreak occurrence.