Chapter 25 BRUCELLOSIS

Medical Aspects of Chemical and Biological Warfare 514 suffering from contagious abortion. 6 In 1917, A. C. Evans recognized that Bang's organism was identical to that described by Bruce as the causative agent of human brucellosis. The organism infects mainly cattle, sheep, goats, and other ruminants, in which it causes abortion, fetal death, and genital infection. 7,8 Humans, who are usually infected incidentally by contact with infected animals or ingestion of dairy foods, may develop numerous symptoms in addition to the usual ones of fever, malaise, and muscle pain. Disease frequently becomes chronic and may relapse, even with treatment. The ease of transmission by aerosol suggests that Brucella organisms might be a candidate for use as a biological warfare agent. Indeed, the United States began development of B suis as a biological weapon in 1942. The agent was formulated to maintain long-term viability, placed into bombs, and tested in field trials during 1944–1945 using animal targets. By 1967, the United States terminated its offensive program for development and deployment of Brucella as a biological weapon. Although the munitions developed were never used in combat, the studies reinforced the concern that Brucella organisms might be used against U.S. troops as a biological warfare agent. thionine or basic fuchsin dyes; agglutination by antisera directed against certain lipopolysaccharide epitopes; and by susceptibility to lysis by bacte-Brucellae are small, nonmotile, nonsporulating, nontoxigenic, nonfermenting, aerobic, Gram-negative coccobacilli that may, based on DNA homol-ogy, represent a single species. 10 Conventionally, however, they are classified into six species, each comprising several biovars. Each species has a characteristic , but not an absolute, predilection to infect certain animal species (Table 25-1). Only Bru-cella melitensis, B suis, B abortus, and B canis cause disease in man. Infection of humans with B ovis and B neotomae has not been described. Brucellae grow best on trypticase, soy-based, or other enriched media with a typical doubling time of 2 hours. Most biovars of B abortus require incubation in an atmosphere of 5% to 10% carbon dioxide for growth. Brucellae may produce urease, oxidize nitrite to nitrate, and are oxidase and catalase positive. Species and biovars are differentiated by their carbon dioxide requirements; ability to use glutamic acid, ornithine, lysine, and ribose; hydrogen sulfide production; growth in the presence of