Stomach flu or seasonal flu?

Do you know the difference between stomach flu, sometimes also called 'gastric flu', and seasonal flu? " Stomach flu" is a popular term but not the true medical diagnosis. The proper medical term for stomach flu is gastroenteritis.

Sometimes people mistake symptoms of stomach flu or gastroenteritis for the viral infection we commonly call 'flu', which has symptoms of high temperature, muscle aches, chills, cough, and fatigue. Learn more about stomach flu and seasonal flu so you can recognise the symptoms and seek proper treatment.

How does stomach flu differ from seasonal flu?

Stomach flu actually refers to gastroenteritis or irritation and inflammation of the stomach and intestines (the gastrointestinal tract). Gastroenteritis may be caused by a virus, bacteria, parasites in spoiled food or unclean water.

Influenza (seasonal flu), on the other hand, is a viral infection that mimics a cold except that it starts forcefully with symptoms of fatigue, high temperature, cough, chills, and muscles aches. While more than 100 different virus types can cause a common cold, only influenza virus types A, B and C cause seasonal flu. More severe cases of influenza can lead to life-threatening illnesses such as pneumonia.

In addition while antibiotics can treat a bacterial infection, antibiotics cannot treat influenza because seasonal flu is caused by a virus.

What are the symptoms of gastroenteritis (stomach flu)?

Symptoms of gastroenteritis or stomach flu include abdominal cramps, stomach pain, nausea, vomiting and diarrhoea. You may also have a high temperature, headache and swollen lymph glands, depending on the type of bug that causes it.

In severe cases of gastroenteritis, loss of bodily fluid can result in dehydration, a life-threatening condition that needs medical attention. Signs of dehydration include sunken eyes, light-headedness, increased thirst, dry or sticky mucus membranes in the mouth, lack of normal elasticity of the skin, decreased urine output and decreased tears.

You can avoid dehydration by continuing to drink fluids and trying to eat as normally as possible. Eating bland foods such as bananas, rice, apple sauce and dry toast is sometimes easier, and these are easily digested and less likely to irritate the sensitive gastrointestinal system.

What causes gastroenteritis (stomach flu)?

There are many causes of stomach flu (gastroenteritis), including bacteria such as E coli, Shigella and Salmonella. Viruses can also cause stomach flu and are responsible for 30% to 40% of gastroenteritis cases in children. Common stomach flu viruses include norovirus or Norwalk virus, adenovirus, rotavirus, calicivirus and astrovirus. Stomach viruses are notorious for spreading rapidly because of poor hand washing.

While not as common, parasites such as giardia and cryptosporidium can cause severe diarrhoea and dehydration. Water-borne parasites are common in underdeveloped parts of the world that have unsanitary water supplies. It is recommended that travellers drink only bottled water to avoid water-borne parasites - a potential cause of gastroenteritis.

A lack of good hygiene can result in gastroenteritis. For instance improper hand washing after going to the toilet or after changing a baby's nappy can spread the infectious bug from person to person. Many doctors call stomach flu "a family affair" because it is so highly contagious and usually goes through all members of a family.