What should you know about a highly contagious stomach bug?

Gastroenteritis irritates the stomach and bowel. Nausea, diarrhoea, abdominal pain, fever, and loss of appetite may occur together or separately. Viruses such as rotavirus can cause this pattern, but bacteria, parasites, food-related illness, and other conditions can look similar.

Spread is more likely when hands are not washed after using the toilet or caring for someone who is sick. Vomit and diarrhoea can contaminate nearby surfaces. Dehydration is the main immediate concern, especially for babies, older adults, and people with other illnesses.

Offer frequent small sips of fluid; an oral rehydration solution can replace water and salts lost through vomiting or diarrhoea. Continue breastfeeding and offer suitable food as tolerated. Wash hands with soap and water, clean contaminated surfaces, avoid preparing food for others while ill, and do not share towels. Stay away from school or work until symptoms have settled according to local advice.

Seek urgent help for severe dehydration, confusion, fainting, blood in vomit or stool, severe abdominal pain, breathing difficulty, or inability to keep fluids down. Arrange prompt medical review for a child who is unusually sleepy, has very few wet nappies, or is worsening. Persistent diarrhoea, high fever, or symptoms after travel also need clinical advice.

Ask whether oral rehydration is suitable, which medicines to avoid, when the person can return to normal activities, whether testing is needed, and which signs indicate dehydration or a more serious illness.