ABSTRACT
I. BACKGROUND Bacillary dysentery, or shigellosis, is caused by infection with bacteria of the genus Shigella. Evidence of dysentery in human populations can be traced back to the writings of Hippocrates, who used the term to describe a condition marked by the passage of bloody and mucoid stools. Shigella are frank pathogens and readily cause disease in humans even when low doses are ingested. This feature of shigellosis gives the pathogen epidemic outbreak potential and can rapidly be disseminated through contaminated food and water. For example, dysentery has played a pivotal role in the outcome of many military operations over the centuries. Prolonged conflicts such as the American Civil War and the Napoleonic campaigns saw more casualties among soldiers and civilians due to disease than to battle. In the twentieth century, shigellosis has been controlled by the introduction of modern methods of wastewater treatment and the availability of potable drinking water in most developed countries. Nevertheless, shigellosis remains endemic in underdeveloped areas where food and water supplies are frequently contaminated by human excrement. Even in developed regions with safe water supplies, a breakdown in the water treatment and distribution infrastructure due to war or natural disasters can place whole populations at risk of infection with a waterborne pathogen such as Shigella.
