Small bowel infections.

Infections of the human gastrointestinal tract with enteric pathogens are among the leading causes of disease, suffering, and death worldwide. Enteric pathogens are ingested from contaminated food and water and pass through the entire gastrointestinal tract during establishment in the host and subsequent shedding and spread to new hosts. Nonetheless, each pathogen exploits a unique niche within the intestinal tract and has developed unique strategies to interact with different host cells and functions. The most important and prevalent infections of the small intestine are caused by diarrheagenic Escherichia coli, particularly enterotoxigenic and enteropathogenic E. coli, rotavirus, Giardia lamblia, and Cryptosporidium parvum. This review focuses on recent insights into the pathogenesis of infections with these pathogens and host defenses against them.