Epidemiology of Infectious Diarrhea

Diarrhea is a very frequent symptom. A great variety of chemical agents, microorganisms, and biotoxins can cause diarrhea, acute or persistent, slight or serious. From the epidemiological point of view, the cases can be sporadic or epidemic, and identification of the infection source and transmission mechanism is important for prevention and control. Knowledge of the etiology is a great help. The entrance route to the human body is usually through the digestive system. From some source in an individual's surroundings, the causal agent somehow reaches the mouth of the susceptible person. The hands play a fundamental role in many situations. This article revises the most important epidemiological characteristics of the agents that produce diarrhea as a main symptom, placing an emphasis on epidemiological point of view and environmental transmission mechanisms. Some aspects regarding individual susceptibility (genetic or other types) are also mentioned. Because the long-term consequences of infectious gastroenteritis are less well known, a small section dedicated to the long-term consequences of infectious gastroenteritis has been included. With suitable prevention, not only the acute consequences but also the aftereffects of these diseases can be avoided.