The investigation to determine what caused 40 people at a Blackpool school to fall ill continued yesterday.
Health experts said they suspected an outbreak at Highfurlong School in Blackpool Old Road was ‘likely’ to be a virus such as the highly-contagious norovirus.
However, a spokeswoman for Public Health England said officials were ‘still waiting on test results’ yesterday.
An investigation into the water supply at the school found no problems, but United Utilities recommended further tests on the internal plumbing are carried out.
The firm said it found ‘nothing that would cause illness’.
Mark McGivern, from the Cumbria and Lancashire Health Protection Team, said it was working with environmental health officers and the council’s health and safety team to ‘investigate the incident and ensure measures are in place to prevent the spread of illness’.
He added: “At this stage it’s not possible to pinpoint exactly the source of the illness and further investigation is ongoing.”
In a letter to parents, headteacher Rosie Sycamore requested details of anyone who has fallen ill in recent weeks. She added: “Bottled water will continue to be used throughout the school for drinking purposes until further notice.”
The school, which is now on a half-term break, has around 50 children on its books, according to its last Ofsted report.
Highfurlong’s neighbouring school, Aspire Academy, was providing staff working over half-time with bottled water ‘as a precaution’.