The previous regulations applied to only 3 infectious diseases: cholera, plague, and yellow fever. IHR (2005) refl ects shifting concepts about disease control, shaped by recent and impending disease threats and the experiences of the past 2 decades in detecting and responding to disease outbreaks. The emergence and reemergence of a cascade of infectious diseases fueled by globalization and international travel (13) , the threat of biological terrorism, and novel environmental threats (14) have spotlighted the need for heightened vigilance and increased capacity to recognize and manage public health risks and emergencies. The appearance and rapid international spread of SARS and the pandemic potential of circulating avian infl uenza (H5N1) strains-with their combined health and economic effects-confi rmed the inapplicability of the 1969 IHR to most emerging and reemerging infectious diseases.