Viral Gastroenteritis
On this page:
- Symptoms
- Causes
- Transmission
- Diagnosis
- Treatment
- Prevention
- Hope Through Research
- Points to Remember
- For More Information
 The digestive system |
Viral gastroenteritis is an intestinal infection caused by several viruses. Viral gastroenteritis is highly contagious and causes millions of cases of diarrhea each year.
Anyone can get viral gastroenteritis and most people recover without any complications. However, viral gastroenteritis can be serious for people who cannot drink enough fluids to replace what is lost through vomiting and diarrhea, especially infants, young children, the elderly, and people with weak immune systems. Complications from vomiting also can occur, even in healthy people.
Symptoms
The main symptoms of viral gastroenteritis are watery diarrhea and vomiting. Other symptoms are headache, fever, chills, and abdominal pain. The symptoms may appear within hours or a few days of infection. They usually last for 1 to 2 days, but may last as long as 10 days.
Causes
The viruses that cause viral gastroenteritis damage the cells in the lining of the small intestine. As a result, fluids leak from the cells into the intestine and produce watery diarrhea. Four types of viruses cause most viral gastroenteritis.
- Rotavirus
is the leading cause of gastroenteritis among children 3 to 15 months
old. Most children have been exposed to the virus by age 2. Children
with rotavirus have vomiting and watery diarrhea for 3 to 8 days,
along with fever and abdominal pain. Rotavirus can also infect adults
who are in close contact with infected children, but the symptoms
in adults are milder. Symptoms of rotavirus infection appear 1 to
2 days after exposure. In the United States, rotavirus infections
are most common from November to April.
- Adenovirus
serotypes 40 and 41 cause gastroenteritis mainly in children younger
than 2 years old. Infections occur all year round; vomiting and
diarrhea appear approximately 1 week after exposure.
- Caliciviruses
cause infection in persons of all ages. This family of viruses is
further divided into the noroviruses (example, Norwalk virus) and
the sapoviruses (example, Sapporo virus). Caliciviruses are transmitted
from person to person and also through contaminated water or food--especially
oysters from contaminated waters. The noroviruses are often responsible
for epidemics of viral gastroenteritis. In addition to vomiting
and diarrhea, people infected with caliciviruses may have muscle
aches. The symptoms appear within 1 to 3 days of exposure.
- Astrovirus
also infects primarily infants, young children, and the elderly.
This virus is most active during the winter months. Vomiting and
diarrhea appear within 1 to 3 days of exposure.
Viral gastroenteritis is often mistakenly called "stomach flu," but it is not caused by the influenza virus and it does not infect the stomach. Also, viral gastroenteritis is not caused by bacteria or parasites. For information about bacterial infections, please see the Bacteria and Foodborne Illness fact sheet from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Transmission
Viral gastroenteritis is highly contagious. The viruses are often transmitted on unwashed hands. People can get the viruses through close contact with infected individuals, such as sharing their food, drink, or eating utensils, or by eating food or drinking beverages that are contaminated with the virus. People who no longer have symptoms may still be contagious, since the virus can be found in the stool for up to 2 weeks after they recover from their illness. Also, people can become infected without having symptoms, and they can still spread the infection.
Outbreaks of viral gastroenteritis can occur in child care settings, schools, nursing homes, cruise ships, camps, dormitories, restaurants, and other places where people gather in groups. If you suspect that you were exposed to a virus in one of these settings, you may want to contact your local health department, which tracks outbreaks.
[Top]
Diagnosis
If you think you have viral gastroenteritis, you may want to see your doctor, although many people don't bother. Doctors generally diagnose viral gastroenteritis based on the symptoms and a physical examination. Your doctor may ask for a stool sample to test for rotavirus or to rule out bacteria or parasites as the cause of your symptoms. No routine tests are currently available for the other types of viruses.
Treatment
Most cases of viral gastroenteritis resolve over time without specific treatment. Antibiotics are not effective against viral infections. The primary goal of treatment is to reduce the symptoms, and prompt treatment may be needed to prevent dehydration.
Your body needs fluids to function. Dehydration is the loss of fluids from the body. Important salts or minerals, known as electrolytes, can also be lost with the fluids. Dehydration can be caused by diarrhea, vomiting, excessive urination, or excessive sweating, or by not drinking enough fluids because of nausea, difficulty swallowing, or loss of appetite.
In viral gastroenteritis, the combination of diarrhea and vomiting can cause dehydration. The symptoms of dehydration are
- excessive thirst
- dry mouth
- little or no urine or dark yellow urine
- decreased tears
- severe weakness or lethargy
- dizziness or lightheadedness
If you notice any of these symptoms, you should talk to your doctor. Mild dehydration can be treated by drinking liquids. Severe dehydration may require intravenous fluids and hospitalization. Untreated severe dehydration can be life threatening.
Children present special concerns. Because of their smaller body size, infants and children are at greater risk of dehydration from diarrhea and vomiting. Oral rehydration solutions such as Pedialyte can replace lost fluids, minerals, and salts.
You can take several steps to help relieve the symptoms of viral gastroenteritis.
- Allow
your gastrointestinal tract to settle by not eating for a few hours.
- Sip
small amounts of clear liquids or suck on ice chips if vomiting
is still a problem.
- Give
infants and children oral rehydration solutions to replace fluids
and lost electrolytes.
- Gradually
reintroduce food, starting with bland, easy-to-digest food, like
toast, broth, apples, bananas, and rice.
- Avoid
dairy products, caffeine, and alcohol until recovery is complete.
- Get plenty of rest.
Prevention
Prevention is the only way to avoid viral gastroenteritis. There is no vaccine available. You can avoid it by
- washing
your hands thoroughly after using the bathroom or changing diapers
- washing
your hands thoroughly before eating
- disinfecting
contaminated surfaces
- not eating or drinking foods or liquids that might be contaminated
Hope Through Research
NIDDK's Division of Digestive Diseases and Nutrition supports basic and clinical research into gastrointestinal diseases, including epithelial cell injury in the gastrointestinal tract. New vaccines under development may decrease the risk of infection, especially among infants and young children.
Points to Remember
- Viral
gastroenteritis is a highly contagious infection of the intestines
caused by one of several viruses.
- Although
it is sometimes called "stomach flu," viral gastroenteritis is not
caused by the influenza virus and does not affect the stomach.
- The
main symptoms are watery diarrhea and vomiting.
- Anyone
can get viral gastroenteritis through unwashed hands, close contact
with an infected person, or food and beverages that contain the
virus.
- Diagnosis
is based on the symptoms and a physical examination. Currently only
rotavirus can be rapidly detected in a stool test.
- Viral
gastroenteritis has no specific treatment; antibiotics are not effective
against viruses. Treatment focuses on reducing the symptoms and
preventing dehydration.
- The
symptoms of dehydration are excessive thirst, dry mouth, dark yellow
urine or little or no urine, decreased tears, severe weakness or
lethargy, and dizziness or lightheadedness.
- Infants,
young children, the elderly, and people with weak immune systems
have a higher risk of developing dehydration due to vomiting and
diarrhea.
- People
with viral gastroenteritis should rest, drink clear liquids, and
eat easy-to-digest foods.
- For
infants and young children, oral rehydration solutions can replace
lost fluids, minerals, and salts.
- Avoid viral gastroenteritis by washing hands thoroughly after using the bathroom or changing diapers, disinfecting contaminated surfaces, and avoiding foods or liquids that might be contaminated.
For More Information
Centers for Disease
Control and Prevention
1600 Clifton Road
Atlanta, GA 30333
Phone: 1-800-311-3435 or (404) 639-3534
Internet: www.cdc.gov