A school in Newcastle has been hit by a winter sickness bug, with staff and students forced out of school.
Health experts are carrying out tests to determine the cause of the vomiting, diarrhoea and flu-like symptoms which swept Heaton Manor school last week.
School leaders say children now seem to be recovering, with more and more coming back to school after a weekend clean.
Heaton Manor head teacher Karen Blackburn said the school had seen "higher than normal absence levels" on Thursday and Friday last week, with students and staff struck by a "heavy cold or sickness bug".
She said cleaning had been increased over the weekend - but that health experts had advised against closing the school.
"We worked closely with Public Health England (PHE) to identify any further risks and sent a notice to all parents to remind them about timescales for their children to return to school following sicknesses of this nature.
"We have also increased our cleaning of the school and have had staff in over the weekend to support this. Public Health England has emphasised that schools should remain open and keep their routine normal.
"I would like to thank parents for their support during this and wish staff and pupils who are still feeling the effects of the illness a speedy recovery.
"Although attendance levels have significantly improved this week, parents of pupils who are still unwell should continue to report the illness through the usual channels."
A spokesperson for PHE said: "North East Health Protect Team and Newcastle City Council are aware of a suspected outbreak of an influenza-like illness and D&V (diarrhoea and vomiting) at Heaton Manor School.
Dr Kirsty Foster, of PHE, said: "Although unpleasant, for most healthy people, flu, flu-like illness and D&V are self-limiting illnesses. Symptoms include sudden onset of fever, cough as well as sore throat, aching muscles and joints.
"The best advice for treating flu in healthy people is to stay at home, rest, drink plenty of fluids and take pain relievers such as paracetamol. Children under 16 should not take any medicines containing aspirin.
"Maintaining good cough and hand hygiene, such as covering your nose and mouth with a tissue when you cough and sneeze, disposing of the tissue as soon as possible and cleaning your hands as soon you can are important actions that can help prevent the spread of germs and reduce the risk of transmission.
"Remember Catch it, Bin it, Kill it”
"People in at risk groups who develop symptoms consistent with flu, or if anyone’s symptoms persist or become more severe, they should seek medical advice."