The search for the source of the maggot infestation at Aberdeen’s Children’s Hospital will continue over the weekend.
It is understood the investigation is now focussing on the roof space above the theatres as opposed to within the theatres themselves.
One of the three operating theatres at the hospital was reopened on Friday after closing as a precaution. The other two remain shut following the discovery of the larvae in both on Thursday.
NHS Grampian confirmed specialists worked until late on Thursday and resumed their investigations on Friday.
Health Secretary Nicola Sturgeon has said she expects the health board to establish and rectify the cause "as quickly as possible".
Alan Pilkington, general manager of child health services for NHS Grampian, said children had never been at risk of coming into contact with the maggots.
"Around 25 maggots were found by cleaners on the floor of theatres, some singly and some in clusters, apparently at various stages of development," he said. "Clearly infestation of this kind is very unpleasant, and our advisors will continue to try throughout the day to identify the source.
"I am satisfied this is not a reflection on staff or standards of cleanliness in the hospital."
The maggots were found in theatres A and C. Theatre B was not affected and was closed initially as a precaution but has been reopened for emergencies.
Two decontamination cleans of all the theatres have so far been carried out.
All scheduled surgical procedures on Monday and Tuesday will go ahead as planned and may take place in the reopened theatre.
A decision on when to re-open the two theatres will be made by infection control officials and clinicians.
The revelation comes in the same week that Aberdeen topped a Scotland-wide table of patients infected with the hospital bug Clostridium difficile. Nearly 5,000 cases of C.difficile were recorded in the year since a deadly outbreak at the Vale of Leven hospital in May 2007. Aberdeen Royal Infirmary topped the list with nearly 440 victims.
