Emerging infectious diseases like AIDS, BSE or avian influenza have been identified by scientific and political authorities as a major threat to human survival. This project explores how the Swiss public thinks about avian influenza, including their perceptions of the threat it poses, its causes, transmission, and prevention. Massive research and policy efforts have been deployed to understand biological aspects of emerging infectious diseases. However, successfully containing them and limiting their impact on humans also requires scientific knowledge about how the public understands and reacts to the threat they pose. There is much less research on these issues. This project focuses on the case of avian flu, which has recently emerged in the public sphere as an acute threat. We adopt a social psychological perspective based on social representations research to study public knowledge of avian flu, its determinants, its variation, and its behavioral consequences. Integrating previous survey, qualitative and experimental research on perceptions of disease, threat, and intergroup relations with social representations theory, we seek to answer four research questions. First, how is public knowledge about avian flu organized? Second, how does knowledge vary according to demographic background and cultural differences? Third, how does knowledge affect relevant behavior (e.g., protection measures, consumer behavior, allocation of resources like medication, avoidance of members of other groups like foreigners or asylum seekers)? Fourth, how do relevant phenomena vary over time, in other words, how do knowledge and behavioral reactions evolve as a function of varying threat levels? This last question is particularly important, because emerging infectious diseases are, by definition, new to the public. Thus, knowledge may develop and change over time (as in the case of AIDS, for example). These questions will be answered in a longitudinal survey of a representative sample of the Swiss public. In addition, interviews will be conducted with smaller samples to explore qualitative aspects of public beliefs. Media analyses will also be conducted. The completed study will yield valuable data on the Swiss public's knowledge and beliefs about avian flu. The data will help us understand how the public reacts to disease-related threats in general. The data will contribute to existing theory in social psychology. Furthermore, the data may have implications for public health issues. For example, they may inform the design of disease prevention campaigns, or may highlight potential collective reactions to an acute pandemic threat.