Viral gastroenteritis is an intestinal infection marked by watery diarrhea, abdominal cramps, nausea or vomiting, and sometimes fever.
The most common way to develop viral gastroenteritis — often called stomach flu —is through contact with an infected person or by ingesting contaminated food or water. If you’re otherwise healthy, you’ll likely recover without complications. But for infants, older adults and people with compromised immune systems, viral gastroenteritis can be deadly.
There’s no effective treatment for viral gastroenteritis, so prevention is key. In addition to avoiding food and water that may be contaminated, thorough and frequent hand-washings are your best defense.
Although it’s commonly called stomach flu, gastroenteritis isn’t the same as influenza. Real flu (influenza) affects only your respiratory system — your nose, throat and lungs. Gastroenteritis, on the other hand, attacks your intestines, causing signs and symptoms, such as:
Watery, usually nonbloody diarrhea — bloody diarrhea usually means you have a different, more severe infection
Abdominal cramps and pain
Nausea, vomiting or both
Occasional muscle aches or headache
Depending on the cause, viral gastroenteritis symptoms may appear within one to three days after you’re infected and can range from mild to severe. Symptoms usually last just a day or two, but occasionally they may persist as long as 10 days.
Because the symptoms are similar, it’s easy to confuse viral diarrhea with diarrhea caused by bacteria, such as Clostridium difficile, salmonella and E. coli, or parasites, such as giardia.
When to see a doctor
If you’re an adult, call your doctor if:
You’re not able to keep liquids down for 24 hours
You’ve been vomiting for more than two days
You’re vomiting blood
You’re dehydrated — signs of dehydration include excessive thirst, dry mouth, deep yellow urine or little or no urine, and severe weakness, dizziness or lightheadedness
You notice blood in your bowel movements
You have a fever above 104 F (40 C)
For infants and children
See your doctor right away if your child:
Has a fever of 102 F (38.9 C) or higher
Seems lethargic or very irritable
Is in a lot of discomfort or pain
Has bloody diarrhea
Seems dehydrated — watch for signs of dehydration in sick infants and children by comparing how much they drink and urinate with how much is normal for them
If you have an infant, remember that while spitting up may be an everyday occurrence for your baby, vomiting is not. Babies vomit for a variety of reasons, many of which may require medical attention.Call your baby’s doctor right away if your baby:
Has vomiting that lasts more than several hours
Hasn’t had a wet diaper in six hours
Has bloody stools or severe diarrhea
Has a sunken soft spot (fontanel)on the top of his or her head
Has a dry mouth or cries without tears
Is unusually sleepy, drowsy or unresponsive.