Which organism is identified as a category A bioterrorism agent in the described scenario?

• A. Francisella tularensis
• B. Bacillus anthracis
• C. Variola virus
• D. Yersinia pestis

Answer: (A)

Category A agents are the highest-priority bioterrorism threats because they can be easily disseminated or transmitted, cause high mortality, and require immediate, broad public health action. Francisella tularensis fits this top tier because it needs only a very small infectious dose by inhalation to cause disease, can be dispersed as an aerosol, and can lead to rapidly progressive, severe illness that would prompt urgent diagnosis, isolation, notification of authorities, contact tracing, and mass prophylaxis and treatment. This combination of easy dissemination potential and serious illness is why it’s identified as a Category A agent in preparedness frameworks. (Note: other well-known Category A agents—such as anthrax, smallpox, and plague—also appear in the high-priority list, and the scenario emphasizing Francisella tularensis reflects its designation within that top category.)