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Viral Gastroenteritis
What is viral gastroenteritis?
Gastroenteritis means inflammation of the stomach and small and large intestines. Viral
gastroenteritis is an infection caused by a variety of viruses that results in vomiting or
diarrhea. It is often called the "stomach flu," although it is not caused by the
influenza viruses.
What causes viral gastroenteritis?
Many different viruses can cause gastroenteritis, including
rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of
Norwalk-like viruses. Viral gastroenteritis is not caused by bacteria (such as Salmonella
or Escherichia coli) or parasites (such as Giardia), or by medications or
other medical conditions, although the symptoms may be similar. Your doctor can determine
if the diarrhea is caused by a virus or by something else.
What are the symptoms of viral gastroenteritis?
The main symptoms of viral gastroenteritis are watery diarrhea and
vomiting. The affected person may also have headache, fever, and abdominal cramps
("stomach ache"). In general, the symptoms begin 1 to 2 days following infection
with a virus that causes gastroenteritis and may last for 1 to 10 days, depending on which
virus causes the illness.
Is viral gastroenteritis a serious illness?
For most people, it is not. People who get viral gastroenteritis almost
always recover completely without any long-term problems. Gastroenteritis is a serious
illness, however, for persons who are unable to drink enough fluids to replace what they
lose through vomiting or diarrhea. Infants, young children, and persons who are unable to
care for themselves, such as the disabled or elderly, are at risk for dehydration from
loss of fluids. Immune compromised persons are at risk for dehydration because they may
get a more serious illness, with greater vomiting or diarrhea. They may need to be
hospitalized for treatment to correct or prevent dehydration.
Is the illness contagious? How are these viruses spread?
Yes, viral gastroenteritis is contagious. The viruses that cause
gastroenteritis are spread through close contact with infected persons (for example, by
sharing food, water, or eating utensils). Individuals may also become infected by eating
or drinking contaminated foods or beverages.
How does food get contaminated by gastroenteritis viruses?
Food may be contaminated by food preparers or handlers who have viral
gastroenteritis, especially if they do not wash their hands regularly after using the
bathroom. Shellfish may be contaminated by sewage, and persons who eat raw or undercooked
shellfish harvested from contaminated waters may get diarrhea. Drinking water can also be
contaminated by sewage and be a source of spread of these viruses.
Where and when does viral gastroenteritis occur?
Viral gastroenteritis affects people in all parts of the world. Each
virus has its own seasonal activity. For example, in the United States, rotavirus and
astrovirus infections occur during the cooler months of the year (October to April),
whereas adenovirus infections occur throughout the year. Viral gastroenteritis outbreaks
can occur in institutional settings, such as schools, child care facilities, and nursing
homes, and can occur in other group settings, such as banquet halls, cruise ships,
dormitories, and campgrounds.
Who gets viral gastroenteritis?
Anyone can get it. Viral gastroenteritis occurs in people of all ages
and backgrounds. However, some viruses tend to cause diarrheal disease primarily among
people in specific age groups. Rotavirus infection is the most common cause of diarrhea in
infants and young children under 5 years old. Adenoviruses and astroviruses cause diarrhea
mostly in young children, but older children and adults can also be affected. Norwalk and
Norwalk-like viruses are more likely to cause diarrhea in older children and adults.
How is viral gastroenteritis diagnosed?
Generally, viral gastroenteritis is diagnosed by a physician on the
basis of the symptoms and medical examination of the patient. Rotavirus infection can be
diagnosed by laboratory testing of a stool specimen. Tests to detect other viruses that
cause gastroenteritis are not in routine use.
How is viral gastroenteritis treated?
The most important of treating viral gastroenteritis in children and
adults is to prevent severe loss of fluids (dehydration). This treatment should begin at
home. Your physician may give you specific instructions about what kinds of fluid to give.
CDC recommends that families with infants and young children keep a supply of oral
rehydration solution (ORS) at home at all times and use the solution when diarrhea first
occurs in the child. ORS is available at pharmacies without a prescription. Follow the
written directions on the ORS package, and use clean or boiled water. Medications,
including antibiotics (which have no effect on viruses) and other treatments, should be
avoided unless specifically recommended by a physician.
Can viral gastroenteritis be prevented?
Yes. Persons can reduce their chance of getting infected by frequent
handwashing, prompt disinfection of contaminated surfaces with household chlorine
bleach-based cleaners, and prompt washing of soiled articles of clothing. If food or water
is thought to be contaminated, it should be avoided.
Is there a vaccine for viral gastroenteritis?
There is no vaccine or medicine currently available that prevents viral
gastroenteritis. A vaccine is being developed, however, that protects against severe
diarrhea from rotavirus infection in infants and young children.
For further information, please contact the Respiratory and Enteric Viruses Branch,
National Center for Infectious Diseases, at 404-639-3577 (telephone) or 404-639-4960
(facsimile).
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