Bacillus anthracis |
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Long regarded as the preferred biological warfare agent, Bacillus anthracis is the causative agent of anthrax. Its potential for use as a bioweapon was infamously demonstrated by the autumn 2001 anthrax letter attacks in the U.S.
Bacillus anthracis is an endospore-forming, Gram-positive rod-shaped bacterium. Within the genus Bacillus, B. anthracis belongs to the Bacillus cereus group, which includes the pathogens B. cereus and B. thuringiensis. B. anthracis has many characteristics of a soil bacterium, and is considered to have evolved from a B. cereus type ancestor through acquisition of plasmid-encoded virulence factors. Anthrax is an acute, infectious disease, and an old nemesis of lower vertebrates, livestock and humans. Despite a decrease in its incidence in developed countries, it remains a health problem in developing countries. It is transmitted to humans by contact with infected animals or inhalation of anthrax spores. Human anthrax has three major clinical forms: cutaneous, inhalational, and gastrointestinal. Symptoms and severity vary depending on the type of infection, but all forms can be fatal if untreated with antibiotics, and inhalational anthrax is particularly lethal. This lethality, combined with the ease of laboratory production and ability to disseminate anthrax spores in aerosol form account for its listing as a category A bacterial pathogen. The complete genome sequence of B. anthracis has identified chromosomally encoded genes that may also contribute to pathogenicity, as well as identified surface proteins that might be targets for vaccines and drugs. Comparative genome studies of B. anthracis with both closely related pathogens of the Bacillus genus, and other more distantly related bacterial pathogens is contributing to our understanding of anthrax, and bacterial pathogenesis in general. Other web resources: TIGR's Anthrax Resource Guide University of Pittsburgh Medical Center: Center for Biosecurity Centers for Disease Control NIAID fact sheet The Bacteria Museum |
