(See also Overview of Incidents Involving Mass-Casualty Weapons Overview of Incidents Involving Mass-Casualty Weapons Mass-casualty weapons are weapons that can produce a mass-casualty incident. Mass-casualty incidents overwhelm available medical resources because they involve so many injured people (casualties)... read more .)
Biological weapons are thought by some to be ideal weapons for terrorists. These agents may be delivered in secret and have delayed effects, allowing the perpetrator to remain undetected.
The US Centers for Disease Control and Prevention (CDC) has created a priority list of biological agents and toxins (see table CDC High-Priority Biological Agents and Toxins CDC High-Priority Biological Agents and Toxins* 
). The highest priority are Category A.
The deliberate use of biological weapons to cause mass casualties would probably entail the use of aerosols. Inhalational anthrax Anthrax Anthrax is a potentially fatal infection with Bacillus anthracis, a gram-positive, rod-shaped bacteria (see figure ). Anthrax may affect the skin, the lungs, or, rarely, the digestive... read more 
and pneumonic plague Plague and Other Yersinia Infections Plague is a severe infection caused by the gram-negative bacteria Yersinia pestis and often involving the lymph nodes and/or lungs. The bacteria are spread mainly by the rat flea. Depending... read more 
are the two diseases most likely to occur under these circumstances.
Recognition of Biological Weapon Injuries
Distinguishing the use of a biological weapon from a natural outbreak of disease may be difficult for doctors. Clues to a deliberate rather than a natural origin of a disease outbreak include the following:
Cases of diseases not usually seen in that geographic area
Unusual distribution of cases among segments of the population
Significantly different illness rates between those inside and those outside buildings
Separate outbreaks in geographically diverse areas
Multiple simultaneous or serial outbreaks of different diseases in the same population
Unusual routes of exposure (such as inhalation)
A disease that normally affects animals occurring in humans
A disease that normally affects animals arising in an area where that animal species is not usually present
Unusual severity of disease
Unusual strains of infectious agents
Failure to respond to standard therapy
The symptoms, diagnosis, and treatment of people with the following diseases caused by high-risk biological weapons are discussed elsewhere in THE MANUALS:
Doctors may need to isolate people exposed to a biological weapon and place under quarantine people known to have been in contact with an exposed person.
Response to Biological Weapon Injuries
Because of the relatively long incubation periods of diseases caused by biological weapons, people will likely be treated in a hospital. People are given vaccines, antibiotics, or antiviral drugs depending on the specific infectious organism involved. Sometimes people who have been in contact with the affected people are given preventive treatment. For many biological weapons, there is no specific treatment or vaccine.
The views expressed in this article are those of the author and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Centers for Disease Control and Prevention: Emergency Preparedness and Response: An alphabetical listing of bioterrorism agents and diseases. Accessed January 4, 2023.
