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.