Anthrax as a biological weapon: an old disease that poses a new threat.

HISTORICAL PERSPECTIVE Bacillus anthracis is a soil bacterium that has been present on earth since ancient times. Anthrax spores can persist in the soil for years, particularly in areas with high levels of soil nitrogen, a pH greater than 6.0, and ambient temperatures greater than 15°C (59°F). Heavy rains after prolonged drought also promote high levels of soil contamination. These factors are thought to help maintain the organism in sufficient quantities to promote infection. Anthrax most commonly occurs in herbivores such as sheep, goats, and cattle when they graze on spore-contaminated soil. Once prevalent, anthrax has been To purchase reprints, contact The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 809-2273 or (949) 362-2050 (ext 532); fax, (949) 362-2049; e-mail, [email protected]. Frederick J. Tasota is a pulmonary clinical specialist who is the project director for the Improving Outcomes in Mechanical Ventilation Grant. He has 23 years of experience in critical care nursing and has written and lectured on a variety of nursing, pulmonary, and critical care topics.