Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning (Part 1) Harrison's Internal Medicine > Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning: Introduction Ranging from mild annoyances during vacations to devastating dehydrating illnesses that can kill within hours, acute gastrointestinal illnesses rank second only to acute upper respiratory illnesses as the most common diseases worldwide. In children <5 years old, attack rates range from 2–3 illnesses per child per year in developed countries to as high as 10–18 illnesses per child per year in developing countries. In Asia, Africa, and Latin America, acute diarrheal illnesses are not only a leading cause of morbidity in children—with an estimated 1 billion cases per year—but also a major cause of death. These illnesses are responsible for 4–6 million deaths per year, or a sobering total of 12,600 deaths per day. In some areas, >50% of childhood deaths are directly attributable to acute diarrheal illnesses. In addition, by contributing to malnutrition and thereby reducing resistance to other infectious agents, gastrointestinal illnesses may be indirect factors in a far greater burden of disease. The wide range of clinical manifestations of acute gastrointestinal illnesses is matched by the wide variety of infectious agents involved, including viruses, bacteria, and parasitic pathogens (Table 122-1). This chapter discusses factors that enable gastrointestinal pathogens to cause disease, reviews host defense mechanisms, and delineates an approach to the evaluation and treatment of patients presenting with acute diarrhea. Individual organisms causing acute gastrointestinal illnesses are discussed in detail in subsequent chapters. Table 122-1 Gastrointestinal Pathogens Causing Acute Diarrhea Mechanism Locati on Illness Stool Findings Exampl es of Pathogens Involved Noninflamma Proxi mal small Watery No fecal leukocytes; Vibrio cholerae, tory (enterotoxin) bowel diarrhea mild or no increase in fecal lactoferrin enterotoxigenic Escherichia coli (LT and/or ST), enteroaggregati ve E. coli , Clostridium perfringens , Bacillus cereus, Staphylococcus aureus, Aeromonas hydrophila, Plesiomonas shigelloides, rotavirus, norovirus, enteric adenoviruses, Giardia lamblia, Cryptosporidiu m spp., Cyclospora spp., microsporidia Inflammatory (invasion or cytotoxin) Colon or distal small bowel Dysent ery or inflammatory diarrhea Fecal polymorphonuc lear leukocytes; substantial increase in fecal lactoferrin Shigella spp., Salmonella spp., Campylobacter jejuni , enterohemorrha gic E. coli , enteroinvasive E. coli , Yersinia enterocolitica, Vibrio parahaemolytic us, Clostridium difficile, ? A. hydrophila, ? P. shigelloides, Entamoeba histolytica Penetrating Distal small bowel Enteric fever Fecal mononuclear leukocytes Salmone lla typhi, Y. enterocolitica, ?Campylobacte r fetus Abbreviations: LT, heat-labile enterotoxin; ST, heat-stable enterotoxin. Source: After Guerrant and Steiner. . Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning (Part 1) Harrison's Internal Medicine > Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial. Chapter 122. Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning Acute Infectious Diarrheal Diseases and Bacterial Food Poisoning: Introduction Ranging from mild annoyances during. manifestations of acute gastrointestinal illnesses is matched by the wide variety of infectious agents involved, including viruses, bacteria, and parasitic pathogens (Table 122- 1). This chapter discusses