Public health emergencies pose special challenges for law enforcement, whether the threat is manmade (e.g., the anthrax terrorist attacks) or naturally occurring (e.g., flu pandemics). Policing strategies will vary depending on the cause and level of the threat, as will the potential risk to the responding officers. In a public health emergency, law enforcement will need to quickly coordinate its response with public health and medical officials, many of whom they may not have worked with previously. Depending on the threat, law enforcement's role may include enforcing public health orders (e.g., quarantines or travel restrictions), securing the perimeter of contaminated areas, securing health care facilities, controlling crowds, investigating scenes of suspected biological terrorism, and protecting national stockpiles of vaccines or other medicines. In a large-scale incident, such as a pandemic, law enforcement resources will quickly become overwhelmed, and law enforcement officials will have to balance their resources and efforts between these new responsibilities and everyday service demands. All of this may have to be accomplished with a greatly diminished workforce, as officers and their families may become infected and ill, and some personnel may determine that the risk of continuing to report to work is just too great to themselves or their families. A department's ability to respond effectively to any emergency--public health or otherwise--greatly depends on its preparedness, and this is directly linked to the law enforcement agency's planning and its partnerships. This document will help state and local law enforcement officials and policymakers to understand communicable diseases (including terminology and methods of transmission) and the threat they pose to public health and safety. The document outlines key concerns that law enforcement officials must address in preparation for a virus-caused pandemic and other public health emergencies and identifies issues that may arise in the department's “all-hazards” approach. The document has three main sections: • Preparing the department (e.g., maintaining operational continuity). • Protecting the officers (e.g., educating them about transmission, vaccination, and treatment). • Protecting the community (e.g., maintaining public order). In addition, five appendixes provide background information and additional resources.