Health officials say the vast majority of children at a Powys nursery can return after being cleared of the E.coli bug.
Forty-five youngsters at Park Lane Day Nursery in Welshpool have now tested negative for the O157 strain of the bacteria.
Screening at the nursery began when two children contracted the stomach infection earlier this month.
However, the nursery is not considered to be the source of the infection.
Dr Mac Walapu, from the National Public Health Service for Wales (NPHS) said: "Screening for E.coli O157 at the Welshpool nursery, where the NPHS were able to confirm two cases, is now nearly complete.
"Forty-five children have been given the all-clear to return to the nursery.
"Following the report of the first case, only one further child was found to have the bug, but this child has now had two clear samples so is no longer carrying the organisms."
Officials were alerted to the first case of E.coli at the nursery on 9 June by a laboratory report and the second case was identified.
Screening
The nursery has remained open, but the families of children screened for the bug were told they could not return until they had two negative tests at least 48 hours apart.
The NPHS has also confirmed that an adult case of E.coli had also been identified in the area, but doctors said this person had no link to the nursery.
Ruling out the nursery as the source of the infection, Dr Walapu added: "E.coli O157 is found quite widely in the environment, particularly among farming communities.
"It is usual for the NPHS to investigate sporadic cases in the community throughout the year in both adults and children."
Symptoms of E.coli O157 can range from mild diarrhoea, stomach cramps and fever to bloody diarrhoea.
The incubation period can range from one to 14 days, but is usually three to four days, and people with E.coli O157 are usually ill for up to two weeks.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~11~RS~)