Guidance for Responding to a Plague Bioterrorism Event

Key points

  • Pneumonic plague is the most likely clinical manifestation following an intentional release of Yersinia pestis.
  • Public health responders should work with medical providers to isolate patients with suspected or confirmed plague, monitor patient outcomes, and report data to state public health authorities.
  • Plague is a very serious illness but is treatable with commonly available antimicrobials.


Although the threat of a bioterrorist attack using Yersinia pestis, the causative agent of plague, is unlikely, there are examples throughout history of Y. pestis being used as a bioweapon. If such an emergency were to occur in the United States, CDC and other federal agencies would work closely with state and local partners to coordinate a response.

Epidemiologic investigation

An epidemiologic investigation should begin as soon as a human case of plague has been detected. Initially, it will be important to determine the source of the infection and whether it was naturally acquired or the result of bioterrorism. If bioterrorism is suspected, a joint investigation by public health and law enforcement officials will be required. The investigation will seek to identify and isolate the affected population and the epidemiologic features of the case(s).

Pneumonic plague is the most likely clinical manifestation following an intentional release of Yersinia pestis. Patients with pneumonic plague pose a risk for person-to-person transmission. When interviewing symptomatic individuals in person, interviewers should take precautions including wearing appropriate personal protective equipment (PPE).

Interviewers should ask patients about:

  • Symptoms, including cough or other respiratory symptoms.
  • Anyone with whom they had close (<6 feet), sustained contact following the onset of cough.
  • Detailed information about places the patient has visited since the onset of cough to determine sites where additional people may have been exposed.

Identification of additional people with symptoms of plague will help investigators find the source of exposure and initiate appropriate treatment for those infected. It is also important to identify others who may have been exposed but not yet developed symptoms, so they can begin immediate antimicrobial prophylaxis and fever watch.

Public health responders should work with medical providers to isolate patients with suspected or confirmed plague, monitor patient outcomes, and report data to state public health authorities.

Enhanced surveillance and case reporting

Detection of human plague cases suspected of being linked to a bioterrorism event will require the state public health authority to initiate and coordinate active surveillance. Additionally, state public health authorities and Centers for Disease Control and Prevention (CDC) staff will coordinate the epidemiologic investigation with other relevant state and federal authorities. Enhanced surveillance plans should include how to:

  • Identify the most likely exposure and ensure rapid identification and reporting of additional cases after an initial case is confirmed (within jurisdiction or elsewhere).
  • Conduct epidemiological analyses to estimate the population at risk, identify unexpected epidemiological features of the outbreak, and evaluate the characteristics and extent of the outbreak to develop the most effective containment and communication strategies.
  • Identify priority groups for consideration of pre-exposure prophylaxis.
  • Identify possible infected animal populations and where environmental evaluation or remediation may be necessary.

Case reporting

Human plague is a nationally notifiable disease, which means cases of plague are reported to state or local health departments by healthcare providers and laboratories. State health departments then classify cases according to standard criteria outlined in the plague case definition and report confirmed and probable cases to CDC. Public health authorities use this information to make informed decisions about the best course of action to stop an outbreak.

Public health authorities might recognize a bioterrorism attack by an increase in reported cases. For example, several cases of pneumonic plague in an area would be considered a public health emergency, prompting public health authorities to respond immediately. Additionally, any case of plague outside areas where plague naturally occurs and in people without history of travel would be cause for added concern.

The extent of the outbreak and the resources available will affect the scope of investigation and how plague cases are reported.

In addition to standard surveillance practices, public health organizations can prepare for surveillance during a bioterrorism event by:

  • Educating medical, veterinary, and public health workers on the case definitions and clinical manifestations of plague.
  • Coordinating laboratory activities through the Laboratory Response Network (LRN) and other facilities.
  • Designating a centralized location for reporting suspect plague cases with 24/7 capability.
  • Identifying suspect cases and testing samples after hours and emergency notification systems and ensuring that on-call staff has appropriate access to communication resources.
  • Developing data management systems for cases of disease and for serious adverse events after postexposure prophylaxis or treatment.


Accurate and timely communication with key audiences will support a successful response to a plague emergency. CDC and other federal agencies will communicate about national-level efforts and assist state and local efforts. State and local public health authorities will be responsible for communicating to people within their jurisdictions about the response efforts that affect them.

Preparing to communicate effectively during a plague emergency is similar to preparing for any public health emergency. Prior emergency response work will be beneficial in informing communications. Below are some tips for public health organizations to prepare to communicate effectively during a plague emergency.

  • Be ready to answer questions from the media and the public about plague. This requires knowledge about clinical disease, how plague is spread, prevention, and recommendations for treatment and prophylaxis. Make sure you have knowledgeable people on staff who are able to talk to the media and the public. CDC's Crisis & Emergency Risk Communications website has trainings and materials to help you prepare.
  • Make arrangements to establish a hotline on short notice.
  • Identify media outlets that can be used to inform the public about actions they should take if they may have been exposed to Y. pestis. Keep in mind special considerations to effectively reach and communicate with community members with functional, language, or cognitive needs.
  • Review rapid-alert communication systems to ensure timely communication capability between the state and local public health and medical communities. Upgrade the systems if necessary.
  • Clearly identify the relative roles of state and local public relations offices.
  • Prepare sample alert messages for the community and other partners. Format these messages for different media, including broadcast, print, web, and social media.
  • Translate messages into languages other than English that are spoken in the community. Confirm accuracy and cultural appropriateness of the messages.