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Wars are an unfortunate but apparently inescapable consequence of human socialization. In the past quarter-century alone, there have been dozens of major armed conflicts worldwide. Several of these wars have been multinational in scope and have involved the deployment of large numbers of ground forces from their home countries to distinct areas of conflict in developing portions of the world, such as southwest and central Asia (e.g., Iraq, Afghanistan) and Africa.
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Troops who are deployed as combatants or in other military capacities on foreign soil are at risk of acquiring infectious diseases endemic to that region on the basis of intimate human and environmental exposures and their immunologic naiveté with regard to local endemic or enzootic pathogens. This risk is magnified by the crowded social conditions engendered by mass troop deployments, infrastructure destruction, and population displacement; it is further amplified by vulnerabilities in public health, such as the lapses in hygiene and sanitation that invariably accompany armed conflicts. The clinical spectrum of infectious illness acquired in this setting includes acute infections in the combat theater, acute infections with delayed symptoms, and chronic or relapsing infections. The latter two scenarios have the potential to cause illness in veterans returning from foreign wars.
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The impact of acute infectious diseases of war, which were once a major cause of noncombat mortality, has significantly lessened in modern conflicts, largely because of the use of preventive vaccines and the early institution of antimicrobial therapy. Nonetheless, these acute diseases remain an important cause of morbidity in deployed military personnel (Table 9-1). Many acute infectious diseases, such as influenza, meningococcal meningitis, hepatitis A, and adenoviral respiratory disease, can largely be prevented by routine vaccination of troops. Others, such as bacterial gastroenteritis and viral respiratory tract infections, continue to represent common causes of minor morbidity among deployed forces. The incidence of several other acute infections, such as malaria and dengue, can be favorably impacted—although not completely abrogated—by the use of chemoprophylaxis, personal protective measures, and vector control. Uncommonly, infections that have short incubation periods and are acquired just days before leaving a combat theater may become clinically manifest only upon the return of troops to their countries of origin. Such was the case in a cluster of African tick typhus that occurred during short-term U.S. troop deployments to Somalia and Botswana in the early 1990s. However, because most acute infections with brief clinical incubation periods are self-limited or responsive to treatment, they are not typically seen in returning war veterans and will not be addressed further in this chapter.
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