In view of the threat of a future pandemic outbreak of any highly pathogenic pathogen strain, including influenza, with possibly devastating numbers of deaths, health authorities all over the world are designing plans to prepare adequate responses to such an outbreak. Possible intervention strategies for pandemic influenza range from treatment with antiviral drugs, contact tracing and isolation, increasing social distances by closing schools and other public meeting places, to vaccination. The use of mathematical and simulation models has become an accepted means to test and evaluate the effectiveness of different interventions. The effectiveness of a response in containing an outbreak is largely determined by three quantities, firstly the completeness, secondly the timeliness and speed of every link in the response chain, and thirdly the effectiveness and coverage of reaching individuals who are targeted by intervention. Completeness is determined largely by the awareness of reporting GP s. Timeliness and choice of interventions are determined by the clinical course of infection and its transmission dynamics and by the diagnostic tools available to (rapidly) identify infected individuals. The problem of underreporting of infectious diseases may serve as an example for the interaction of infection, response chain and control measures. Another point of attention is the behavior of populations. Understanding and making use of the influence of social networks and the underlying mechanisms of decision in conflicts between individual and population interests will greatly enhance the ability of rapid response mechanism to adequately roll out public health interventions. Aim of the project : The aim of this project is to develop a theoretical framework in which to (a) classify (newly emerging) pathogens according to properties that determine in which way they challenge the public health response; (b) identify the steps of the response chain that constitute an adequate response to any outbreak; (c) identify the extent of underreporting for notifiable diseases; (d) develop a mathematical model that can simulate and analyse the interaction between pathogens and a generic outbreak intervention; (e) use the model to identify the crucial and possibly weak links in the response chain, quantify their expected duration based on empirical data, and quantify the effectiveness of interventions; (f) investigate how the properties of the interaction between outbreak of a pathogen and public health response might change in times of crisis; (g) formulate recommendations for a flexible and regionally oriented intervention strategy; (h) evaluate how changes in reporting responsibilities as defined by the new law on Public Health might affect timeliness and reporting; (i) identify region specific key components for improvement of the reporting to respond chain.