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Foodborne and Waterborne Illness: Overview and Risk Factors

Foodborne and waterborne illnesses are common, but often unrecognized. They cause an estimated 76 million illnesses, 300,000 hospitalizations, and 5,000 deaths yearly in the United States.1,2 The most prominent symptom is acute diarrhea, but the associated dehydration may lead to electrolyte irregularities, acute renal failure, and encephalopathy. Rarely, food or waterborne illness may be associated with prolonged or more severe complications, such as anemia, shock, hemolytic–uremic syndrome, spontaneous abortion, seizures, and liver, heart, or lung disease. Many illnesses carried by food or water are particularly common in the developing world, due to poor sanitation, polluted water, and lack of refrigeration. However, developed countries are by no means exempt. About 20% of all US diarrheal episodes are believed to be caused by foodborne or waterborne illness.3

This chapter focuses mainly on acute diarrheal illnesses, but also includes information on prions and other rare diseases that are part of the full scope of foodborne and waterborne illness.

Risk Factors

Risk factors for specific pathogens are presented below.

Age. Young children are the most likely to have acute diarrhea. Institutionalized elderly persons are also at higher risk.

Medications. Antibiotic use alters the normal gut flora, and H2–receptor blockers or other medications may increase gastric pH. Both of these factors increase susceptibility to foodborne illness.

Food traditions. Intentionally undercooked or raw meats and fish (eg, steak tartare, sushi, and oysters) increase the risk of foodborne illness. This is a particular concern in patients with advanced liver disease or immunocompromised states, such as T–cell immunodeficiencies.

Hygiene. The spread of disease is facilitated by environments where unpolluted water is not available, infected food handlers expose others to pathogens, or sanitary hand washing is not possible (or may be improperly done, as in the case of children at daycare facilities).


Foodborne and Waterborne Illness: Diagnosis >>