forces with infectious hepatitis during the North African campaign and the wide variety of infectious diseases that affected American warfighters in Vietnam. Although the use of vaccines against plague and cholera significantly minimized the incidence of those diseases among U.S troops in Vietnam (Ellenbogen, 1982; Ognibene, 1987), diseases for which vaccines were not available—for example, leptospirosis, meliodosis, and shigellosis—were prevalent (Ognibene, 1987). Even in recent years, U.S. troops have been deployed to geographic regions where there exist endemic infectious disease agents against which the U.S. military does not have immediately available either suitable, safe, and effective vaccines or appropriate chemoprophylactic agents. Infectious diseases continue to contribute substantially to morbidity during deployments, as shown in Figure 1-1.
The severity of the threat to military operations from infectious diseases has been recognized since the beginning of the science of microbiology and has prompted a substantial body of military research on the subject and many advances in public health. A better understanding of many infectious agents and their mechanisms of transmission have come from careful studies of epidemics in military populations and from research done by military epidemiologists and microbiologists. Two examples are Sir Ronald Ross’s studies on the role of the