Which of the following agents is classified as a Category A biological agent?

The classification of biological agents into categories is based on factors such as ease of transmission, potential for public health impact, and the ability to cause widespread panic and social disruption. Category A biological agents are those that pose the highest risk to national security and public health.

Plague, caused by the bacterium Yersinia pestis, is classified as a Category A agent due to its high virulence, potential for rapid spread, and historic significance as a cause of epidemics. It can be transmitted through respiratory droplets, especially in its pneumonic form, making it a serious concern for bioterrorism. The potential for high mortality rates and the requirement for specific public health preparedness measures underscore its classification.

In contrast, other agents listed might not have the same level of public health impact, transmission potential, or historical significance as plague. Hantavirus, while serious, is generally transmitted through rodent contact and does not have the same potential for rapid person-to-person spread. Typhus, primarily spread by lice or fleas, while impactful, is less associated with bioterrorism risks. Botulism, caused by a toxin, is also a serious condition but is less transmissible and typically associated with foodborne outbreak scenarios.

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