What should you know about stomach bug infection?

Viruses are common causes, although bacteria, parasites, contaminated food or water and other conditions can produce similar symptoms. Gastroenteritis may present with nausea, vomiting, loose stools, abdominal cramps, fever and reduced appetite. Diarrhoea is a common presentation of gastroenteritis, but it does not reveal which germ is involved. Rotavirus infection is one recognised cause, especially in children. Symptoms and exposure history help a clinician decide whether further assessment is needed.

Replace lost fluid with frequent small sips of water or oral rehydration solution. Rest and eat modest portions when you feel able. Wash hands with soap and water after the toilet and before food; clean shared bathroom surfaces and avoid preparing meals for others while ill. Do not share towels or utensils. Keep a note of vomiting, stool changes, drinking and urination, particularly when caring for a child.

Speak with a clinician if you cannot keep fluids down, symptoms are getting worse or they fail to settle. Seek urgent help for blood in stool, severe abdominal pain, fainting, confusion, breathing trouble, very little urine or unusual sleepiness. Dehydration deserves earlier attention in babies, older adults, pregnancy and people with chronic or immune conditions. A clinician can distinguish gastroenteritis from problems needing different treatment.

Ask which fluids and foods suit you, whether medicines are appropriate, when you can return to work or school, and whether testing is needed.