Viral Diarrhea in Small Children – Stomach Flu Symptoms, Treatment

Diarrhea is the leading cause of death in children around the globe. While this is often linked to a lack of clean drinking water and unavailability of medical care in most developing nations, diarrhea can also lead to death even in developed countries. Infants, young children and the elderly are at the greatest risk. However, most cases of acute diarrhea in children are not usually serious and resolve within a few days without medical intervention.

What Causes Diarrhea in Small Children?

The main cause of diarrhea in children under 5 years of age is viral gastroenteritis. The most common virus responsible is rotavirus which causes gastroenteritis – inflammation of the inner layer of the stomach and small intestine. This may also involve the colon in some cases. The virus is easily transmitted among children, particularly those in close contact like siblings and within daycare centers.

The main complication from viral diarrhea, as is the case with most other causes of diarrhea, is dehydration. It can be prevented with the continuous rehydration with an appropriate oral rehydrating solution (ORS). In severe cases, intraveouns (IV) rehydration may be necessary. The viral infections resolves quickly with symptoms usually easing within 2 to 3 days.

Symptoms of Stomach Flu

Symptoms of a rotavirus infection resemble the flu (influenza). Hence the the term stomach flu although viral gastroenteritis is not caused by any strain of the influenza virus. While there is no connection between stomach flu and influenza, sometimes viral gastroenteritis can follow a bout of the flu or vice versa. Symptoms of stomach flu (viral diarrhea) include:

  • Fever, malaise (feeling of being unwell), lethargy and even headaches precede the onset of the gastrointestinal symptoms.
  • Watery diarrhea and vomiting appear 1 to 2 days after the infection and usually last for 3 to 8 days (1). Sometimes vomiting is minimal and depending on the cause of the infection, it may event be absent.
  • Symptoms of dehydration such as dryness of the mouth, skin and eyes, drowsiness or restlessness, thirst (which may not always be present), decreased urination or, in severe cases, sunken eyes, sunken fontanel, and decreased consciousness, arise after there is significant fluid and electrolyte loss due to vomiting and diarrhea. It may be minimal if there is proper rehydration.

In the Western world, rotavirus diarrhea is usually a mild disease, but in some parts of Africa, Middle and South America and south Asia over 1 million of children die from this infect every year. Death is mainly due to dehydration.

How is Stomach Flu Spread?

Rotavirus is spread by mainly by the hands and surfaces contaminated with fecal particles. It can cause outbreaks in facilities like daycare centers and this mostly occurs in the winter. Foodborne and waterborne infection are also possible, but droplet infection (saliva or nasal mucus) is less likely. The stool of infected children is highly contagious several days before the onset of the diarrhea, and for up to 10 days after diarrhea has stopped. In some children and adults, the infection may show no symptoms but their stool is still contagious.

Diagnosis of Stomach Flu

A medical professional may reach a diagnosis of viral gastroenteritis entirely on the symptomatic presentation. In some instances where there is uncertainty about the cause of the diarrhea, a stool test may be conducted to confirm viral gastroenteritis or other causes of diarrheal illnesses.

Other causes of diarrhea in small children:

  • Acute viral diarrhea may also be caused by other viruses: adenovirus, enteroviruses, noroviruses, influenza virus, measles (in non-vaccinated children), and so on.
  • Intestinal parasites, like giardia or Entamoeba hystolytica (from contaminated drinking water) usually cause mild, but prolonged (weeks) diarrhea; diagnosis is by stool test for ova and parasites (O&P test).
  • Bacterial infection due to food poisoning .
  • Early introduced solid food, change of diet, overfeeding, drinking a lot of fruit juices (toddler’s diarrhea).
  • Lactose intolerance causes digestive symptoms and diarrhea within hours of consuming dairy.
  • In fructose malabsorption diarrhea and bloating appear several hours after fructose-rich meal.
  • Malnutrition due to starvation, intestinal parasites, lack of vitamins or minerals, like zinc, in the food.

Treatment of Stomach Flu

Diarrhea usually resolves on its own within a week. Often the only treatment needed is fluid replacement using non-prescription oral rehydrating solutions available in supermarkets and drug stores. These solutions have the optimal balance of electrolytes and fluid to both prevent and treat dehydration.

If the diarrhea does not stop within 5 days, a child appears irritated or drowsy (symptoms of dehydration) or cannot ingest food or fluid. Medical attention is necessary at this point as rehydration has to be done intravenously and commenced as soon as possible to prevent further complications or even to prevent death.

Read more on how to treat watery diarrhea.

Stomach Flu Prevention and Vaccines

The risk of infection may be reduced by washing hands before eating and cleaning stool-contaminated surfaces. A child with diarrhea should stay at home and even a healthy child should not attend daycare during a rotavirus epidemic. Contact between siblings should be minimized up to a few days after infection unless both siblings have contracted the infection.

An oral vaccine RotaTeq, which prevents diarrheal disease in over 70% of rotavirus infections, is available in the United States and Canada. A vaccine is given in the first year of life in three doses together with other childhood vaccines. No serious side effects are known to occur despite unfounded claims about vaccines causing permanent disorders and diseases (2). A comparable vaccine Rotarix is available in Europe and some other countries.

Can Rotavirus Diarrhea Affect the Child Several Times?

Subsequent infections immediately thereafter are usually of decreasing severity since there is some dehree of immunity against the virus. However, future infections can still be relatively intense and it is important to verify whether these infections are due to rotavirus or some other virus, bacteria or protozoa. The vaccine provides significant protection in preventing rotavirus diarrhea but does not entirely preclude to possibility of future infections.

Related Articles:


  1. Rotavirus  (
  2. Rotateq vaccine  (
About Jan Modric (209 Articles)
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