As sites where naturally occurring or deliberately caused infectious diseases are often identified for the first time, emergency departments have become a vital component of public health surveillance networks. Fever represented the primary symptom in more than 4.4 million patients who visited US emergency departments in 2006.1 In addition to the infectious diseases that regularly occur throughout communities worldwide, emergency departments often represent the location at which newly emerging outbreaks are first diagnosed, and decisions made there affect the entire community. For example, during the 2002-2003 outbreak of severe respiratory distress syndrome, the son of a local index patient, while being treated in the open area of a Toronto hospital emergency department, was administered oxygen and nebulized bronchodilators, and received visitors, contributing to the nosocomial dissemination of the virus to other patients, health care staff, and visitors.2 Furthermore, emergency departments are likewise confronted with an additional, exceptional challenge. Of the 11 patients with pulmonary anthrax affected during the 2001 attack(s), 9 presented directly to hospitals or emergency departments,3 illustrating that these locations are often the first place at which deliberately caused public health emergencies are diagnosed.