Anthrax, a potentially fatal infection, is a virulent and highly contagious disease. Descriptions of this disease begin in antiquity, with the best ancient account being by the Roman poet Virgil. During the 19th century, anthrax was the infection involved in several important medical developments. It served as the prototype for Koch's postulates regarding the causation of infectious disease. The first vaccine containing attenuated live organisms was Louis Pasteur's veterinary anthrax vaccine. In the 1900s, human inhalation anthrax occurred sporadically in the United States among textile and tanning workers, but the incidence of the illness had declined dramatically. An outbreak of inhalation anthrax occurred in Sverdlovsk near a Soviet military microbiology facility in 1979. This epidemic represented the largest documented outbreak of human inhalation anthrax in history. In October and November 2001, 22 cases of confirmed or suspected inhalation and cutaneous anthrax were reported associated with the intentional release of the organism in the United States. An additional case of cutaneous disease occurred in March of 2002.