2 Infectious Gastroenteritis and Colitis Jennifer

In this chapter, we discuss the epidemiology, etiology, presentation, diagnosis, and treatment of infectious diarrhea in immunocompetent persons. The features of small intestinal and ileocolonic disease as related to possible causative agents are presented. Additionally, there is an emphasis on specific pathogens, with a comprehensive review of viral, bacterial, and parasitic causes of diarrhea. We then discuss the intricacies of the clinical and diagnostic evaluation, as well as treatment. Specifically, we evaluate the severity of illness, historical clues to etiology, the appropriateness of diagnostic testing in various clinical situations, and which diagnostic tests are clinically relevant. Rehydration therapy is discussed along with nutrition and electrolyte