Anthrax, Smallpox, Botulism: The Terrorist's Biological Weapons of Choice

Often called the "poor man's atomic bomb," the biological agents used in bioterrorism are relatively easy to cultivate, conceal, transport, and disseminate. In most cases, terrorists don't even require sophisticated training to manufacture the bacteria, as the information is readily available in open-source literature, including the Internet. The notable exception is anthrax.
 
Symptoms of exposure to these biological agents are delayed, often for days, making it difficult to identify the perpetrator. In addition to the ease of concealment and transportation, bioterrorism is appealing to terrorists because of its potency: Small amounts can produce many casualties.
 

A case of bioterrorism: In 1984, members of the Bhagwan Shree Rajneesh (a.k.a. Osho) cult intentionally contaminated the salad bars at ten Oregon restaurants with Salmonella, infecting more than 750 people.

Anthrax

An estimated one kilogram of aerosolized Bacillus anthracis could produce as many as 3 million deaths.
 
While it is found naturally in livestock, weaponizing anthrax can be difficult. Anthrax spores tend to clump together so they aren't easily inhaled; they must be freeze-dried and ground to a suitable size. Even then, anthrax is not easily spread. Standard crop dusting equipment produces droplets that are too large and anthrax delivered in the mail often sticks to the paper rather than becoming aerosolized when the envelope is opened.

Anthrax occurs in three forms:

  • cutaneous (skin)
  • gastrointestinal
  • inhalation.

Symptoms usually appear within seven days of exposure. All forms of anthrax can be fatal if not treated. Because anthrax is generally not passed from person to person, it won't spread through the population like smallpox or plague.

Anthrax in the mail: In September and October of 2001, many people were exposed to inhalation anthrax, which killed five and infected seventeen. The majority of those infected were known or suspected to have handled mail contaminated with anthrax spores. To date, no one has claimed responsibility for the attacks. The FBI continues to investigate and as of August 2004 may be close to finding the person behind the attacks.

Smallpox

While a naturally occurring case of smallpox has not been seen since 1977, two labs store the virus for study and vaccine manufacture should the need arise. Smallpox is a potentially dangerous biological weapon in the hands of a person with the right financial backing and knowledge of microbiology. Aerosolization, as with a crop duster, would be an effective method of smallpox dissemination if the weather conditions were just right.
 
Smallpox symptoms develop after an incubation period of 7 to 17 days, starting with a high fever and progressing to a body-wide rash within two to three. Smallpox is highly contagious, especially during the first week of illness, and is passed through contact with infected saliva droplets, as occur with coughing or sneezing. Smallpox has a high fatality rate of 30 percent. Treatment is limited to supportive therapy and antibiotics for secondary infection.

Botulism Toxin

Several countries have manufactured and stockpiled botulism toxin for use as a biological weapon. Very little of the toxin in needed to produce inhalation botulism, one of the four types of botulism and the one most likely to be used by bioterrorists.

While contaminating a food or beverage supply with Clostridium botulinum would be the easiest method of botulism bioterrorism it would not produce the number of causalities that inhalation botulism could produce, especially because it is destroyed by heat.

Botulism toxin affects the central nervous system causing paralysis, difficulty swallowing and breathing, and impaired vision, among other symptoms. Foodborne botulism toxin would also cause gastrointestinal problems.

Mortality rate from botulism poisoning is related to the severity of symptoms. Accurate diagnosis is important, and rapid administration of antitoxin can reduce the risk of a fatal outcome.