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Is It a Stomach Flu or Influenza?

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What Causes a Stomach Flu? continued...

Bacteria that cause gastroenteritis include:

Viruses are responsible for 30% to 40% of gastroenteritis cases in children, and may include:

  • Norovirus or Norwalk-like virus
  • Adenovirus
  • Rotavirus
  • Calicivirus
  • Astrovirus

Stomach viruses are notorious for spreading rapidly because of poor hand washing.

While not as common, parasites such as giardia and cryptosporidium can cause severe diarrhea and dehydration. Water-borne parasites are common in underdeveloped parts of the world that have unsanitary water supplies. It is recommended that travelers drink bottled water to avoid water-borne parasites.

Some foods may irritate your stomach and also cause gastroenteritis. Reaction to dairy products in someone with lactose intolerance is the most common example. Severe reactions to seafood is another example.

A lack of good hygiene can result in a stomach flu. For instance, improper hand washing after using the bathroom or after changing a baby's diaper can spread the infectious bug from person to person. Many doctors call stomach flu "a family affair" because it is so highly contagious and usually goes through all members of a family.

Who's at Risk for Stomach Flu?

Those at high risk for stomach flu include pregnant women, infants, undernourished and immune-compromised people, and older adults.

In addition, the severity of infectious gastroenteritis depends on your immune system's ability to resist the infection. 

When Should You Call the Doctor About Stomach Flu?

If you experience symptoms of stomach flu and are weak and dizzy, you may be dehydrated. If you cannot drink fluids and continue to lose fluids through fever, vomiting, and diarrhea, you should call your doctor. If you are sleepy or unaware, you should be taken to a doctor or hospital's emergency department as soon as possible. Other signs that warrant medical treatment include:

  • Blood in the vomit or stool
  • Dehydration (check for little to no urination, extreme thirst, lack of tears, and dry mouth)
  • Fever higher than 101 degrees Fahrenheit
  • Swollen abdomen or abdominal pain in the right lower part of the abdomen
  • Vomiting that lasts more than 48 hours

WebMD Medical Reference

Reviewed by Kimball Johnson, MD on June 11, 2012
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