Biological Weapons

ByJames M. Madsen, MD, MPH, University of Florida
Reviewed/Revised Oct 2024
VIEW PROFESSIONAL VERSION

Biological warfare is the use of microbiological agents as weapons. Such use is contrary to international law and has rarely taken place during formal warfare in modern history, despite the extensive preparations and stockpiling of biological agents carried out during the 20th century.

(See also Overview of Incidents Involving Mass-Casualty Weapons.)

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 U.S. 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). 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 and pneumonic plague are the 2 diseases most likely to occur under these circumstances.

Table
Table

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 medications 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.

More Information

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

  1. Centers for Disease Control and Prevention: Emergency Preparedness and Response: Bioterrorism Agents/Disease: An alphabetical listing of bioterrorism agents and diseases. Accessed October 3, 2024.

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free MSD Manual App iOS ANDROID
Download the free MSD Manual App iOS ANDROID
Download the free MSD Manual App iOS ANDROID