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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 adults and even more in children, and may include:

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. Call your doctor if you have these symptoms. Also if you cannot drink fluids and continue to lose fluids through fever, vomiting, and diarrhea, get emergency medical help. If you are passing out, someone should call 911. Other signs that warrant medical evaluation and 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 100.4 degrees Fahrenheit or higher in an infant or higher than 102.2 degrees Fahrenheit in an older child or adult.
  • 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 Melinda Ratini, DO, MS on March 28, 2015
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