Gastroenteritis is a very common condition that causes diarrhoea and vomiting. It’s usually caused by a bacterial or viral tummy bug. It affects people of all ages, but is particularly common in young children.
Most cases in children are caused by a virus called rotavirus. Cases in adults are usually caused by norovirus (the “winter vomiting bug”) or bacterial food poisoning.
Gastroenteritis can be very unpleasant, but it usually clears up by itself within a week. You can normally look after yourself or your child at home until you’re feeling better.
Gastroenteritis, also known as infectious diarrhea, is inflammation of the gastrointestinal tract; the stomach and small intestine. Symptoms may include diarrhoea, vomiting and abdominal pain. Fever, lack of energy and dehydration may also occur.
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 are otherwise healthy, you will 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.
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.
You are most likely to contract viral gastroenteritis when you eat or drink contaminated food or water, or if you share utensils, towels or food with someone who’s infected.
A number of viruses can cause gastroenteritis, including:
Noroviruses: Both children and adults are affected by noroviruses, the most common cause of foodborne illness worldwide. Norovirus infection can sweep through families and communities. It’s especially likely to spread among people in confined spaces. In most cases, you pick up the virus from contaminated food or water, although person-to-person transmission also is possible.
Rotavirus: Worldwide, this is the most common cause of viral gastroenteritis in children, who are usually infected when they put their fingers or other objects contaminated with the virus into their mouths. The infection is most severe in infants and young children.
Adults infected with rotavirus may not have symptoms, but can still spread the illness of particular concern in institutional settings because infected adults unknowingly can pass the virus to others. A vaccine against viral gastroenteritis is available in some countries, including the United States, and appears to be effective in preventing the infection.
Some shellfish, especially raw or undercooked oysters, also can make you sick. Although contaminated drinking water is a cause of viral diarrhea, in many cases the virus is passed through the fecal-oral route that is, someone with a virus handles food you eat without washing his or her hands after using the toilet.
Signs and symptoms
Viral gastroenteritis, commonly called stomach flu, gastroenteritis is not 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 diarrhoea bloody diarrhoea usually means you have a different, more severe infection, abdominal cramps and pain, nausea, vomiting or both, occasional muscle aches or headache and low-grade fever.
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 diarrhoea caused by bacteria, such as clostridium difficile, salmonella and E. coli, or parasites, such as giardia.
In most cases, people with viral gastroenteritis get better without medical treatment. You can treat viral gastroenteritis by replacing lost fluids and electrolytes to prevent dehydration. In some cases, over-the-counter medicines may help relieve your symptoms.
Research shows that following a restricted diet does not help treat viral gastroenteritis. When you have viral gastroenteritis, you may vomit after you eat or lose your appetite for a short time. When your appetite returns, you can most often go back to eating your normal diet, even if you still have diarrhea.
If your child has symptoms of viral gastroenteritis, such as vomiting or diarrhoea, don’t hesitate to call a doctor for advice.
Replace lost fluids and electrolytes: When you have viral gastroenteritis, you need to replace lost fluids and electrolytes to prevent dehydration or treat mild dehydration. You should drink plenty of liquids. If vomiting is a problem, try sipping small amounts of clear liquids.
Most adults with viral gastroenteritis can replace fluids and electrolytes with liquids such as: water, fruit juices, sports drinks and broths.
Eating saltine crackers can also help replace electrolytes: If your child has viral gastroenteritis, you should give your child an oral rehydration solution such as pedialyte, naturalyte, infalyte, and ceralyte as directed to replace lost fluids and electrolytes. Oral rehydration solutions are liquids that contain glucose and electrolytes. Talk with a doctor about giving these solutions to your infant. Infants should drink breast milk or formula as usual.
Older adults, adults with a weakened immune system, and adults with severe diarrhoea or symptoms of dehydration should also drink oral rehydration solutions.
In some cases, adults can take over-the-counter medicines such as loperamide (imodium) and bismuth subsalicylate (pepto-bismol, kaopectate) to treat diarrhoea caused by viral gastroenteritis.
These medicines can be unsafe for infants and children. Talk with a doctor before giving your child an over-the-counter medicine.
If you have bloody diarrhoea or fever signs of infections with bacteria or parasites don’t use over-the-counter medicines to treat diarrhoea.
The best way to prevent the spread of intestinal infections is to follow these precautions:
Get your child vaccinated: A vaccine against gastroenteritis caused by the rotavirus is available in some countries, including the United States. Given to children in the first year of life, the vaccine appears to be effective in preventing severe symptoms of this illness.
Wash your hands thoroughly: And make sure your children do, too. If your children are older, teach them to wash their hands, especially after using the toilet. It’s best to use warm water and soap and to rub hands vigorously for at least 20 seconds, remembering to wash around cuticles, beneath fingernails and in the creases of the hands. Then rinse thoroughly. Carry sanitizing wipes and hand sanitizer for times when soap and water aren’t available.
Use separate personal items around your home: Avoid sharing eating utensils, drinking glasses and plates. Use separate towels in the bathroom.
Keep your distance: Avoid close contact with anyone who has the virus, if possible.
Disinfect hard surfaces: If someone in your home has viral gastroenteritis, disinfect hard surfaces, such as counters, faucets and doorknobs, with a mixture of 2 cups (0.47 liters) of bleach to 1 gallon (3.8 liters) of water.
Check out your child care center: Make sure the center has separate rooms for changing diapers and preparing or serving food. The room with the diaper-changing table should have a sink as well as a sanitary way to dispose of diapers.
Take precautions when traveling
When you’re traveling in other countries, you can become sick from contaminated food or water. You may be able to reduce your risk by following these tips:
•Drink only well-sealed bottled or carbonated water.
•Avoid ice cubes, because they may be made from contaminated water.
• Use bottled water to brush your teeth.
• Avoid raw food including peeled fruits, raw vegetables and salads that has been touched by human hands.
• Avoid undercooked meat and fish.
Gastroenteritis occurs all over the world, affecting people of every age, race and background.
People who may be more susceptible to gastroenteritis include:
Young children: Children in child care centers or elementary schools may be especially vulnerable because it takes time for a child’s immune system to mature.
Older adults: Adult immune systems tend to become less efficient later in life. Older adults in nursing homes, in particular, are vulnerable because their immune systems weaken and they live in close contact with others who may pass along germs.
Schoolchildren, churchgoers or dormitory residents: Anywhere that groups of people come together in close quarters can be an environment for an intestinal infection to get passed.
Anyone with a weakened immune system: If your resistance to infection is low for instance, if your immune system is compromised by HIV/AIDS, chemotherapy or another medical condition you may be especially at risk.
Each gastrointestinal virus has a season when it’s most active. If you live in the Northern Hemisphere, for instance, you are more likely to have rotavirus or norovirus infections between October and April.
The main complication of viral gastroenteritis is dehydration a severe loss of water and essential salts and minerals. If you’re healthy and drink enough to replace fluids you lose from vomiting and diarrhoea, dehydration shouldn’t be a problem.
Infants, older adults and people with suppressed immune systems may become severely dehydrated when they lose more fluids than they can replace. Hospitalisation might be needed so that lost fluids can be replaced intravenously. Dehydration can be fatal, but rarely.