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Vol 5 Issue 6 |
November/December 2001 |
Biological Terrorism
Since October 3, 2001, the CDC and state and local public health authorities have been investigating cases of bioterrorism-related anthrax. Both clinicians and laboratorians should be vigilant for symptoms or laboratory findings that suggest or indicate Bacillus anthracis infection (or any other rare bacterial or viral diseases), particularly among mail handlers.
Biological terrorism is defined as the intentional or threatened use of viruses, bacteria, fungi or toxins from living organisms to produce death or disease in humans, animals, or plants. Clues that may signal a bioterrorism attack include:
¨ large number of ill persons with a similar syndrome;
¨ increased incidence of a stable endemic disease;
¨ single case of a disease due to an uncommon agent;
¨ atypical presentation for a population;
¨ unusual disease presentation;
¨ increase in unexplained diseases or death;
¨ disease with an unusual geographic distribution;
¨ disease with an unusual seasonal onset;
¨ atypical transmission by aerosols, food or water that indicates sabotage; and
¨ unusual bacterial strain or antibiotic susceptibility.
This Newsletter will summarize and emphasize the most important points regarding the current situation, with respect to the anthrax material being sent through the mail.
1. B. anthracis, the etiologic agent of anthrax, is a large, gram-positive, non-motile, spore-forming bacterial rod. The three virulence factors of B. anthracis are edema toxin, lethal toxin and a capsular antigen. Human anthrax has three major clinical forms: cutaneous, inhalation (pulmonary), and gastrointestinal.
2. Cutaneous anthrax - the native type and most common form of anthrax seen in the US. The spore passes through the skin (cut or insect bite) and causes a painless (though may be "itchy"), swollen ulcer to develop. First a vesicle forms, then the roof of the lesion comes off, revealing a blackish base called an eschar. Once the ulcer has formed, the vegetative bacterium may then extend into the lymphatic and blood channels to bring about systemic illness and death in 10-20% of untreated individuals.
3. Pulmonary anthrax - the most deadly form of anthrax. In this anthrax variant, the spores are inhaled and begin to grow in the lungs. From the lungs, the organisms are carried into adjacent lymph nodes and through the bloodstream to the entire body. After a few days to a week, flu-like symptoms develop, with increasing