Soldiers must be ready and capable to conduct the full range of military operations to defeat all enemies regardless of the threats they pose. But bad sanitation can keep them from the mission.
According to a 2010 public health report from the U.S. National Library of Medicine National Institute of Health, "Influenza and pneumonia killed more American soldiers and sailors during the war [World War I] than did enemy weapons." The pandemic traveled with military personnel from camp to camp and across the Atlantic in 1918, infecting up to 40 percent of soldiers and sailors. In this instance, the enemy came in the form of a communicable disease.