Bioterrorism is the deliberate release of viruses, bacteria, toxins, or other agents
to cause illness or death in people, animals, or plants. According to experts, the threat of global bioterrorism is increasing. In October 2001, bioterrorism became a reality when letters containing powdered anthrax
were sent through the U.S. Postal Service. The attack caused 22 cases of illness, 5 of which resulted in death, and widespread fear.
The skills and equipment for making a biological weapon are widely known because they are the same as those required for cutting-edge work in medicine, agriculture, and other fields.
Biological agents are in some ways the perfect weapon of terror. They can be spread through the air, water, or food. Terrorists may choose these agents because they can be extremely difficult to detect and do not cause illness for several hours to several days after exposure, meaning that public health officials may not notice the attack until it is too late. Deadly pathogens
are highly accessible. With the exception of smallpox, they all occur naturally in the wild—in soil, air, water, and animals. And the skills and equipment for making a biological weapon are widely known because they are the same as those required for cutting-edge work in medicine, agriculture, and other fields.
High-priority organisms or toxins that pose the greatest risk to national security are known as Category A agents, according to the National Institute of Allergy and Infectious Diseases (NIAID
). These deadly pathogens could be readily spread in the environment or transmitted from person to person, triggering public panic and requiring special public health precautions.
Many public health officials believe that anthrax is the bioweapon of greatest concern—although in the case of the 2001 anthrax mailings in the United States there was less morbidity
than many feared would occur. The infection is caused by Bacillus anthracis
, a bacterium that forms spores. Anthrax does not spread from person to person but rather by hard-coated bacterial spores that spring to life under the right conditions. Anthrax can cause skin lesions
and gastrointestinal disease. Inhalation anthrax is the rarest form of the infection—and may be the most difficult to treat.
An investigator carefully examines one of the letters tainted with anthrax following the 2001 attack in the United States. (www.fbi.gov)
Another disease of concern is smallpox
, a serious, contagious, and sometimes fatal infection. Smallpox was officially declared eradicated from the globe in 1980, after an 11-year WHO
vaccination campaign—the first human disease to be eliminated as a naturally spread contagion
. Once the disease was gone, routine vaccination of the general public ceased. Today, the virus remains only in laboratory stockpiles. But in the aftermath of the events of September and October 2001, concern has grown that the smallpox virus might be used as an agent of bioterrorism.
Another threat—the botulinum
toxin—is the most lethal compound known. The nerve toxin is produced by the bacterium Clostridium botulinum
. Researchers estimate that as little as a gram of aerosolized botox could kill more than 1.5 million people.
NIAID is developing tools to detect and counter the effects of a bioterrorist attack, including vaccines to immunize the public against diseases caused by bioterrorism agents, diagnostic tests to help first responders and other medical personnel rapidly detect exposure and provide treatment, and therapies to help patients exposed to bioterrorism agents regain their health.