Two new cases of E-coli have been confirmed by health officials at a nursery school near Lurgan, Co Armagh.
A total of 14 children at Holly House in Dollingstown are now infected with the bug following an outbreak last week.
It is understood none of the children are seriously ill.
The Public Health Agency said it is continuing to investigate the outbreak.
Dr Neil Irvine, Consultant in Health Protection at the Public Health Agency said: "Further cases may occur due to household transmission of E coli 0157. "
"As part of standard procedures, we are screening household contacts of confirmed cases. Contacts have been given advice to reduce the risk of spreading the infection."
"The PHA continues to monitor the situation and is working closely with the nursery to ensure all infection control measures are being taken."
There is no evidence at this stage as to the source of the infection.
© UTV News