Biological Threats

Biological threats include a variety of biological agents (viruses, bacteria, or other germs) that cause infectious diseases.  They can naturally occur or be intentionally altered to cause severe illness.  The Centers for Disease Control and Prevention (CDC) has divided the agents which can be used as biological weapons into three categories: Category A, B, and C.

Category A

Although these agents are rarely seen in the United States, we must prepare for them because they pose the highest risk to the public and national security.  Specifically 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; and,
  • Require special action for public health preparedness.

The CDC has classified six Category A biological agents.  They are listed below.

Anthrax

Anthrax is a disease caused by the spore-forming bacteria Bacillus anthracis. There are three types of anthrax: skin (cutaneous), lungs (inhalation), and digestive (gastrointestinal).  More information about anthrax.

Smallpox

Smallpox is a contagious, and sometimes fatal infectious disease.  There is no specific treatment for smallpox disease; the only prevention is vaccination.  The name smallpox is derived from the Latin word for “spotted” and refers to the raised bumps that appear on the face and body of an infected person.  More information about smallpox.

Botulism

Botulism is a muscle-paralyzing disease caused by a toxin made by a bacterium called Clostridium botulinum.  There are three main kinds of botulism: foodborne, infant, and wound.  Botulism is not spread from one person to another.  Foodborne botulism can occur in all age groups.  More information about botulism.

Plague

Plague is an infectious disease caused by the bacterium Yersina pestis that affects animals and humans. The bacterium is found in rodents and their fleas and occurs in many parts of the world, including the United States.  There are several forms of plague including: pneumonic, bubonic, and septicemic.  Depending upon the circumstances, these forms may occur separately or in combination.  More information about plague.

Tularemia

Tularemia is caused by the bacterium Francisella tularensis found in animals (especially rodents, rabbits, and hares) and occurs naturally in the United States. Tularemia is not known to spread from person-to-person.  More information about tularemia.

Viral Hemorrhagic Fevers

Viral hemorrhagic fevers (VHFs) refer to a group of illnesses that are caused by several distinct families of viruses.  These viruses naturally reside in animals or insects.  While some types of hemorrhagic fever viruses can cause mild illnesses, many of these viruses cause severe, life-threatening disease.  More information about VHFs.

Category B

These agents are the second highest priority because they:

  • Are moderately easy to spread;
  • Result in moderate illness rates and low death rates; and,
  • Require specific enhancements of CDC’s laboratory capacity and enhanced disease monitoring.
  • Examples include: salmonella, typhus, and ricin.

Category C

These third highest priority agents include emerging pathogens that could be engineered for mass spread in the future because:

  • Are easily available;
  • Are easily produced and spread; and,
  • Have potential for high morbidity and mortality rates and major health impact.
  • Examples include: Nipah virus and hantavirus.