Hospital patients and staff in Brighton have been struck down by an infectious stomach bug.
Two wards have been closed and about 20 patients are suffering from the condition, commonly known as winter vomiting disease.
One ward at Brighton General Hospital and another at the Royal Sussex County Hospital have been affected.
The virus is not life-threatening but gives people sickness and diarrhoea so elderly or frail patients can be vulnerable.
Brighton and Sussex University Hospitals NHS Trust's infection control team is working to contain the bug and new patients will not be admitted to the affected wards until all sufferers have recovered and the area has been cleaned.
Staff are taking extra precautions to prevent the bug from spreading.
Cases have been appearing at both hospitals and at the Princess Royal Hospital in Haywards Heath during the last three months affecting more than 40 staff and patients.
The virus usually appears in hospitals between November and April every year and hospital bosses say the number of cases this year are lower than last year.
A hospital spokesman said: "We are working to deal with the problem which is something that affects many hospitals at this time of year.
"If anyone planning to visit the hospitals is showing symptoms of the virus we would ask them keep away until they have recovered."
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