Diarrheal disease due to infectious enteritis remains a significant global health burden, accounting for 1 in 9 child deaths worldwide, and is the second leading cause of mortality in children less than 5 years of age in resource-poor countries. In the United States, it is estimated that young children have 1 to 3 episodes of diarrhea each year, with the highest rates reported in those attending childcare centers. This chapter will focus on common enteric pathogens causing acute diarrhea in children.
PATHOGENESIS AND EPIDEMIOLOGY
Many enteric pathogens cause gastrointestinal (GI) infections in children, especially in those less than 5 years of age (Table 231-1). These pathogens are acquired via the fecal-oral route directly from another person or indirectly following ingestion of food or water contaminated with feces. Person-to-person transmission generally requires only a low-dose inoculum to produce infection and has a short incubation period.
TABLE 231-1COMMON AGENTS CAUSING GASTROINTESTINAL INFECTIONS IN CHILDREN ||Download (.pdf) TABLE 231-1COMMON AGENTS CAUSING GASTROINTESTINAL INFECTIONS IN CHILDREN
|Bacteria ||Viruses ||Parasites |
|Aeromonas species ||Adenovirus ||Cryptosporidium parvum |
|Bacillus cereus ||Astrovirus ||Cyclospora cayetanensis |
|Campylobacter species ||Enterovirus ||Entamoeba histolytica |
|Clostridium difficile ||Norovirus ||Giardia lamblia |
|Clostridium perfringens ||Rotavirus ||Isospora belli |
|Escherichia colia ||Sapovirus ||Microsporidia |
|Plesiomonas shigelloides || || |
|Salmonella species || || |
|Shigella species || || |
|Staphylococcus aureus || || |
|Vibrio species || || |
|Yersinia enterocolitica || || |
Enteric pathogens cause diarrhea by altering the balance between secretion and absorption of fluids and electrolytes in the GI tract. This can occur by means of a direct effect on enterocyte ion transport and the tight junction barrier or indirectly through virulence factors that cause inflammation. Based on pathophysiology, infectious diarrhea can be categorized as secretory, osmotic, or inflammatory. Secretory diarrhea is the result of active water loss into the GI tract with minimal inflammation, as is classically described with infections such as Vibrio cholerae. Osmotic diarrhea occurs when there is failure to absorb solutes, which then retain water within the GI tract (eg, consuming undiluted concentrated formula). Damage to enterocytes can result in transient lactase deficiency, which in turn results in lactose malabsorption. Inflammatory diarrhea occurs when pathogens, or their enterotoxins, damage enterocytes, leading to villous destruction and impaired water absorption. Infections caused by Salmonella and Clostridium difficile primarily cause inflammatory diarrhea and are characterized by detection of polymorphonuclear white cells in stool.
In cases of suspected infectious enteritis, epidemiologic risk factors may allow consideration of a specific pathogen. Exposures to animals (eg, reptiles), contaminated water, travel to endemic areas, recent receipt of antibiotics, or attendance at a childcare center are important risk factors. For example, Giardia and Cryptosporidium are the most common gastrointestinal infections reported with waterborne outbreaks. Outbreaks of enteric infections in children ...