Bioterrorism agents are divided into three categories based on their ease of spread and the severity of illness they cause. Category A agents are most dangerous, and Category C agents are current emerging threats.


Category A

Category A pathogens are those organisms/biological agents that pose the highest risk to national security and public health because they:

• Can be easily spread or transmitted from person to person
• Result in high death rates and have the potential for major public health impact
• Might cause public panic and social disruption
• Require special action for public health preparedness.


Category B

Category B pathogens are the second highest priority organisms/biological agents. They:

• Are moderately easy to disseminate
• Result in moderate morbidity rates and low mortality rates
• Require specific enhancements for diagnostic capacity and enhanced disease surveillance.


Category C

Category C pathogens are the third highest priority and include emerging pathogens that could be engineered for mass dissemination in the future because of:

• Availability
• Ease of production and dissemination
• Potential for high morbidity and mortality rates and major health impact.


For more information on preparedness activities focused on specific agents, and to learn how to prepare for a bioterrorism-related emergency, view the Bioterrorism, Chemical, Radiological, and Nuclear Emergencies page. For more information on agents of bioterrorism, please visit the CDCs website.


Types of Bioterrorism-Related Diseases: