Gastroenteritis Health Article

Definition

Gastroenteritis is an inflammation of the digestive tract, particularly the stomach, and large and small intestines. Viral and bacterial gastroenteritis are intestinal infections associated with symptoms of diarrhea, abdominal cramps, nausea, and vomiting.

Description

Gastroenteritis is an uncomfortable and inconvenient ailment, but is rarely life-threatening in the United States and other developed nations. Viral gastroenteritis is frequently referred to as the stomach or intestinal flu, although the influenza virus is not associated with this illness.

Demographics

Viral gastroenteritis is one of the most common acute (sudden-onset) illnesses in the United States, with millions of cases reported annually. Each year, an estimated 220,000 children younger than age five are hospitalized with gastroenteritis symptoms. Of these children, 300 die as a result of severe diarrhea and dehydration. In developing nations, diarrheal illnesses are a major source of mortality.

Causes

Gastroenteritis is caused by the ingestion of viruses, certain bacteria, or parasites. Food that has spoiled may also cause illness. Young children may develop signs and symptoms of gastroenteritis as a reaction to a new food.

VIRAL INFECTION Viral infection is the most common cause of gastroenteritis. Viral gastroenteritis is highly contagious and can be spread through close contact with an infected person. Exposure also can occur through the fecal-oral route, such as by consuming foods or beverages contaminated by fecal material related to poor sanitation or poor hygiene, or by touching contaminated surfaces and then touching the mouth and ingesting the germs. The four types of viruses that cause most viral gastroenteritis include rotavirus, adenovirus, calicivirus, and astrovirus.

Typically, children ages three to 15 months are more vulnerable to rotaviruses, the most significant cause of acute watery diarrhea. Outbreaks of diarrhea caused by rotaviruses are common during the winter and early spring months, especially in child care centers. Symptoms in children last for three to eight days, and occur one to two days after exposure to the virus. Worldwide, rotaviruses are estimated to cause 800,000 deaths annually in children under five years of age. For this reason, much research has gone into developing a vaccine to protect children from this virus. Adults can be infected with rotaviruses, but these infections typically have minimal or no symptoms.

Children under age two are more susceptible to adenovirus serotypes 40 and 41. Vomiting and diarrhea symptoms occur about one week after exposure to the virus.

Calciviruses cause infection in people of all ages. This family of viruses includes the noroviruses (such as the Norwalk virus) and the sapoviruses (such as the sapporo virus). Calciviruses are transmitted from person-to-person contact, as well as through contaminated water or food. These viruses are the most likely to produce vomiting as a major symptom. Muscle aches also are common symptoms. The symptoms usually appear within one to three days after exposure to the virus.

Astrovirus primarily infects infants, young children, and the elderly. This virus is most active during the winter months. Symptoms of vomiting and diarrhea appear within one to three days after exposure to the virus.

BACTERIAL AND PARASITIC INFECTIONS Bacterial gastroenteritis is frequently a result of poor sanitation, the lack of safe drinking water, or contaminated food (conditions common in developing nations). Natural or man-made disasters can worsen underlying problems in sanitation and food safety.

In developed nations, including the United States, bacterial gastroenteritis may result from contaminated water supplies, improperly processed or preserved foods, or person-to-person contact in places such as child-care centers. The modern food production system potentially exposes millions of people to disease-causing bacteria through its intensive production and distribution methods. Common types of bacterial gastroenteritis can be linked to Salmonella and Campylobacter bacteria. However, Escherichia coli (E. coli) 0157:H7 and Listeria monocytogenes, bacterial causes of food borne illnesses, have caused increased concern in developed nations.

Cholera and Shigella remain two diseases of great concern in developing countries, and research to develop long-term vaccines against them is underway. Shigella bacteria are dangerous because they attack the intestinal wall and cause bleeding ulcers.

Parasitic infections that cause gastroenteritis are most commonly caused by Giardia, which is easily spread through contaminated water and human contact. Cryptosporidium is another common parasitic organism that causes the symptoms of gastroenteritis.