Avian influenza or bird flu refers to "influenza caused by viruses adapted to birds". Of the greatest concern is the highly pathogenic avian influenza (HPAI). Most human contractions of the avian flu are a result of either handling dead infected birds or from contact with infected fluids. In this book, the authors discuss the molecular evolution, outbreaks and prevention/control of avian influenza. Topics include the risk assessment of highly pathogenic avian influenza virus infections through water; biosecurity measures against highly pathogenic avian influenza (HPAI) in free-range flocks and commercial poultry in developing countries; outbreak control and viral evolution of the highly pathogenic H5N1 avian influenza in Thailand; and the changes in perceptions and attitudes that were identified in a follow-up survey conducted when bird flu was not the focus on widespread media coverage in Australia.