What Are The Causes Of Acute Gastroenteritis In Humans?

According to the 2008 edition of "Harrison's Principles of Internal Medicine," acute gastroenteritis ranks second only to respiratory infections as the most common cause of disease around the world. In developing countries where access to modern medical care is limited, acute gastroenteritis can lead to death, especially in children. Acute gastroenteritis is caused by viruses, bacteria and parasites. In most cases, contaminated food and water serve as the vehicle of infection.

Viruses

According to the Centers for Disease Control and Prevention, viruses that cause acute gastroenteritis in humans include rotavirus, adenovirus, calcivirus, astrovirus, norovirus and sapovirus species. Symptoms usually begin one or two days after exposure and resolve within one to 10 days. Drugs do not treat viral gastroenteritis. The mainstay of treatment is oral rehydration and, if that fails, intravenous rehydration.

Bacteria

According to Medline Plus, a publication of the National Institutes of Health, bacteria implicated in acute gastroenteritis include Campylobacter jejuni, Escherichia coli and several species of clostridium, salmonella, shigella, staphylococcus and yersinia. Some infections result in bloody diarrhea, which should be evaluated by a physician. Cases that last longer than a few days or produce unusually severe symptoms may warrant antibiotics. However, most cases resolve on their own in a few days.

Parasites

The American Association of Clinical Chemistry explains that examination of stool for ova and parasites diagnoses gastroenteritis due to parasites such as giardia, entamoeba histolytic and cryptosporidium. Risk factors for these infections include travel outside the United States and ingestion of water from streams and lakes. Parasites are difficult to treat and frequently produce bloody diarrhea. Unlike gastroenteritis caused by viruses and bacteria, parasitic infections rarely resolve on their own, so persistent diarrhea provides an important diagnostic clue.