and possible quarantine, which would complicate medical and public health management.

Currently in the United States, there is no available plague vaccine. The live vaccines that are sometimes used in other countries have unacceptable adverse effects. However, a number of laboratories are attempting to develop a new-generation vaccine, as well as new delivery methods. Several different types of antibiotics that can be used to treat plague are included in the national pharmaceutical stockpile. Antibiotic treatment must be instituted early in the course of infection; otherwise death occurs in 3 to 6 days.

Tularemia

Francisella tularensis was weaponized as an aerosol in both the United States and the former Soviet Union, where it was also engineered for vaccine resistance (Dennis et al., 2001). In the WHO modeling scenario of 1970, a 50 kg release over a city of 5 million would incapacitate 250,000 people and cause 19,000 deaths (WHO, 1970). Tularemia is highly infectious but not contagious. Treatment is similar to that for plague but more extensive, as is the post-prophylaxis to prevent relapse. The tularemia vaccine is a live attenuated vaccine that was previously available as an investigational drug through the U.S. Department of Defense and is now being investigated by the Joint Vaccine Acquisition Program. However, it does not offer full protection against inhalational transmission, and about 14 days is required for protection to develop. The vaccine has been recommended for use in people who work routinely with the organism in the laboratory, but how useful it would be among first responders at high risk for exposure is unknown.

Botulinum Toxin

Botulinum toxin has several features that make it an attractive bioweapon, including its extreme potency and lethality; the ease of its production, transport, and misuse; and its profound impact on its victims as well as the health care infrastructure. Botulinum toxin is readily available as a bioweapon because of the relative ease with which its source, C. botulinum, can be isolated from nature or otherwise obtained. A minimal amount of laboratory equipment and microbiological expertise is needed to cultivate C. botulinum and concentrate its toxin to weaponized material for oral intake. Like tularemia, botulinum toxin can be transmitted through diverse modes: it can spread through foods or beverages or as an aerosol. The toxin, of which there are seven serotypes, kills by paralyzing its victims’ ability to carry out normal respiratory function and is the most poisonous substance known. One gram, evenly aerosolized and inhaled, could gener-



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