Bacillus anthracis, commonly known, as anthrax is a zoonotic disease caused by endosporic bacterium. The disease commonly occurs in wild and domestic herbivores. Bacillus anthracis is a member of a species of aerobic, spore producing, gram- positive, non-motile, rod-shaped bacteria that are ubiquitous in nature. Bacillus anthracis is the only obligate Bacillus pathogen in vertebrates. A number of other species, in particular Bacillus cereus, are occasional pathogens of both humans and livestock, but the large majority of Bacillus species are harmless saprophytes. The Bacillus species are used in many medical, pharmaceutical, agricultural, governmental and industrial processes that take advantage of their wide range of physiological characteristics and their ability to produce a vast array of enzymes, antibiotics, toxins, and other substances. .
Anthrax is primarily a disease of herbivores. The bacterium exists in a vegetative state in animals and humans and form spores when they have contact with oxygen. The spores are extremely resistant to disinfectants and physical destruction. Humans contract the disease as a result of contact with infected animals or infected animal byproducts. However, anthrax can also be transmitted intentionally. Direct person-to-person transmission is extremely unlikely to occur. In humans the disease may take on one of three forms, depending on how the individual is infected. Cutaneous anthrax, which accounts for more than 95 percent of cases worldwide, results from infection through skin lesions; intestinal anthrax results from ingestion of spores; and pulmonary anthrax results from the inhalation of spores. .
Cutaneous anthrax, the most common form of the disease, usually occurs through contamination of a cut or an abrasion in the skin. After a two to three day incubation period, a small pimple or papule appears at the entry site and a surrounding ring of vesicles develop.
