Outbreaks of gastroenteritis (gastro) are common at this time of the year. Gastro is highly infectious and can spread rapidly to others.

Gastro is an infection of the stomach and bowel, usually by a virus or bacterium. The main symptoms are diarrhoea (frequent or watery bowel motions), nausea, vomiting, abdominal cramps and gas. There may also be fever, headache and aches and pains. Symptoms usually settle within 3 or 4 days.

Most cases are caused by close contact with an infected person (e.g. sharing eating utensils, changing nappies) or from contaminated food and water.

How to treat gastroenteritis

The main risk from gastroenteritis is severe loss of fluids (dehydration). Keep up your liquid intake by drinking small amounts of clear fluids frequently, such as diluted juice or soft drink (1 part to 4 parts boiled water). Commercial rehydration solutions are also available.

Small, light meals can be eaten if you are hungry and not vomiting. Avoid fatty, heavy or spicy foods and milk products.

Medication is sometimes helpful for diarrhoea. Loperamide is effective and well tolerated. It is available as both a capsule and as a preparation which dissolves on the tongue. It also comes as a chewing tablet combined with simethicone to relieve abdominal pain and bloating. 'Diphenoxylate + atropine' and codeine are also effective. Antibiotics are rarely needed.

When to see the doctor

• Always for small children and the elderly.
• If you have a chronic illness e.g. diabetes.
• If you have a fever over 38.5⁰C, shivers, sweats or severe vomiting.
• If you have blood in your motions.
• If you have travelled overseas recently.
• If thirsty or if your urine is dark brown.
• If you are not improving in 48 hours.