I, 1.Viral causes of gastroenteritis.

This chapter discusses the causative viral agents, pathophysiology, and immunology of gastroenteritis. Acute gastroenteritis is among the most common illnesses of humans and is caused by a variety of agents, including bacteria, viruses, parasites, toxins, and chemicals. The clinical spectrum ranges from asymptomatic or mild infection to severe dehydrating illness with a fatal outcome; the latter occurs primarily in young children and in the elderly. The chapter concludes with a discussion on the prevention and treatment of gastroenteritis. For the prevention of epidemic viral gastroenteritis, efforts need to be focused on caliciviruses. No specific antiviral therapy is recommended for childhood viral gastroenteritis, emphasizing the importance of distinguishing it from the selected forms of bacterial and parasitic gastroenteritis that require treatment. Other than pertinent epidemiologic information, certain clinical features of illness may provide etiologic clues, but they are not highly discriminating. Standard therapy of viral enteric infections relies on maintenance of adequate hydration and electrolyte balance. Oral rehydration therapy (ORT) is the main treatment.