Stomach Flu (Viral Gastroenteritis)

Location of stomach organs
Digestive system: Esophagus, gallbladder, liver, stomach, sigmoid colon, duodenum, pancreas, colon, small intestine, anus, rectum Diagram
Heartspring.net © 2013

By the National Digestive Diseases Information Clearinghouse

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Stomach Flu Symptoms
Stomach Virus Causes
Transmission
Diagnosis
Treatment
Prevention
Hope Through Research
Points to Remember
For More Information

Stomach Flu (Viral Gastroenteritis) is an intestinal infection caused by several different viruses. Highly contagious, Stomach Flu (Viral Gastroenteritis) is the second most common illness in the United States. It causes millions of cases of diarrhea each year.

Anyone can get Stomach Flu and most people recover without any complications. However, Stomach Flu can be serious when people cannot drink enough fluids to replace what is lost through vomiting and diarrheaespecially infants, young children, the elderly, and people with weak immune systems.

Stomach Flu Symptoms

The main symptoms of Stomach Flu (Viral Gastroenteritis) are watery diarrhea and vomiting. Other symptoms are headache, fever, chills, and abdominal pain. Symptoms usually appear within 4 to 48 hours after exposure to the virus and last for 1 to 2 days, though symptoms can last as long as 10 days.

Stomach Flu Causes

The viruses that cause Stomach Flu (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 Stomach Flu (Viral Gastroenteritis).

Rotavirus is the leading cause among children 3 to 15 months old and the most common cause of diarrhea in children under the age of 5 years. Symptoms of rotavirus infection appear 1 to 2 days after exposure. Rotavirus typically causes 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. In the United States, rotavirus infections are most common from November to April.
Adenovirus occurs mainly in children under the age of 2 years. Of the 49 types of adenoviruses, one strain affects the gastrointestinal tract causing vomiting and diarrhea. Symptoms typically appear 1 week after exposure. Adenovirus infections occur year round.
Caliciviruses cause infection in people of all ages. This family of viruses is divided into 4 types, the noroviruses being the most common and most responsible for infecting people. The noroviruses are usually responsible for epidemics of Stomach Flu (Viral Gastroenteritis) and occur more frequently from October to April. Infected people experience vomiting and diarrhea, fatigue, headache, and sometimes 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.

Stomach Flu (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, Stomach Flu (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).

Stomach Virus Transmission

Stomach Flu (Viral Gastroenteritis) is highly contagious. The viruses are commonly transmitted by people with unwashed hands. People can get the viruses through close contact with infected individuals by sharing their food, drink, or eating utensils, or by eating food or drinking beverages that are contaminated with the virus. Noroviruses in particular, are typically spread to other people by contact with stool or vomit of infected people and through contaminated water or food—- especially oysters from contaminated waters.

People who no longer have symptoms may still be contagious, since the virus can be found in their 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 Stomach Flu (Viral Gastroenteritis) can occur in households, 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 or by foods prepared on the premise of places such as a restaurant, deli, or bakery, you may want to contact your local health department, which tracks outbreaks.

Stomach Virus Diagnosis

If you think you have Stomach Flu (Viral Gastroenteritis), you may want to see your doctor. Doctors generally diagnose Stomach Flu (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.

Stomach Virus Treatment

Most cases of Stomach Flu (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, excessive sweating, or by not drinking enough fluids because of nausea, difficulty swallowing, or loss of appetite.

In Stomach Flu (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.

The following steps may help relieve the symptoms of Stomach Flu (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.

Stomach Flu Prevention

Prevention is the only way to avoid Stomach Flu (Viral Gastroenteritis). No vaccine is available. You can avoid infection by

washing your hands thoroughly for 20 seconds after using the bathroom or changing diapers
washing your hands thoroughly for 20 seconds before eating
disinfecting contaminated surfaces such as counter tops and baby changing stations
not eating or drinking foods or liquids that might be contaminated

Hope Through Research

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), through its Division of Digestive Diseases, 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.

Important Points to Remember

Stomach Flu (Viral Gastroenteritis) is a highly contagious infection of the intestines caused by one of several viruses.
Although sometimes called "stomach flu," 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 Stomach Flu (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.
Stomach Flu (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 Stomach Flu (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 Stomach Flu (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

Stomach Flu Symptoms by the Center for Disease Control and Prevention.

Page Updated: January 2013

In Stomach Flu (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

Diarrhea in American Infants and Young Children in the Community Setting

By the Slone Epidemiology Center at Boston University, Harvard Medical School and the Digestive Diseases Research Center, Tufts-New England Medical Center, Boston, MA; and the section University of Maryland School of Medicine, Baltimore, MD.

OBJECTIVE:: The characteristics and microbiology of the full spectrum of pediatric diarrhea occurring in the U.S. community setting are not well-understood.

METHODS:: Six-month prospective cohort study of 604 healthy 6- to 36-month-old children recruited by the Slone Center Office-based Research Network. RESULTS:: The incidence of parent-defined diarrhea was 2.2 episodes per person-year. The median duration of diarrhea was 2 days with a median of 6 stools per episode. Outpatient visits and hospitalization were prompted by 9.7 and 0.3% of episodes, respectively. The most common microorganisms identified in healthy baseline stools were atypical enteropathogenic Escherichia coli (12.2%), enteroaggregative Escherichia coli (3.7%), Clostridium difficile (3.5%) and Clostridium perfringens (2.9%), and each of these was no more common in diarrhea stools. In contrast, all of the viruses analyzed were more prevalent in diarrhea specimens than in baseline specimens: enteric adenovirus (5.7% diarrhea versus 1.4% baseline), rotavirus (5.2% versus 1.4%), astrovirus (3.5% versus 1.4%), Sapporo-like virus (3.0% versus 0.8%) and norovirus (1.9% versus 0.8%). A likely pathogen was detected in 20.6% of diarrhea specimens. Vomiting and >/=16 stools in an episode were predictive of isolating a pathogen from the stool, each with a relative risk of approximately 2.

CONCLUSIONS:: Healthy young children in this study experienced more than 2 cases of diarrhea per person-year, but most were brief and do not require medical attention. Although most diarrhea-associated pathogens were viruses, no likely pathogen was found in almost 80% of cases; possible etiologies for these cases include currently unknown gastrointestinal infections, nongastrointestinal illnesses and dietary/environmental factors.

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Selective stimulation of he growth of anaerobic microflora in the human intestinal tract by electrolyzed reducing water

By the Department of Physiology of Microorganisms, Lomonosov Moscow State University

96-99% of the "friendly" or residential microflora of intestinal tract of humans consists of strict anaerobes and only 1-4% of aerobes. Many diseases of the intestine are due to a disturbance in the balance of the microorganisms inhabiting the gut. In this work, it is suggested that prerequisite for the recovery and maintenance of obligatory anaerobic microflora in the intestinal tract is a negative ORP value of the intestinal milieu. Electrolyzed reducing water with E(h) values between 0 and -300 mV produced in electrolysis devices possesses this property. Drinking such water favours the growth of residential microflora in the gut. Continue