If the patient is very young, elderly, or malnourished, dehydration can be life-threatening. Children with diarrhea must be closely monitored. They have not developed the immunities of adults, and their systems can be quickly overwhelmed by the sheer number of pathogens. As many as one-third of pediatric deaths in developing countries are attributed to diarrhea and the resulting dehydration. Vibrio cholerae, Salmonella sp., and Shigella species of bacteria are among the leading causes of bacterial diarrhea.
Bacteria are everywhere, including in our water.
However, water supplies are monitored to prevent contamination by fecal pathogens in concentrations that will produce infections in humans. If these organisms rise above a set level, fecal contamination has occurred and more intensive water testing should begin. It may be necessary to accelerate water treatment procedures. Also, the source of contamination must be located and protective measures taken to avoid further contamination. Until recently, Americans have regularly suffered through epidemics of waterborne illness such as cholera and typhoid fever.