THE family of the Tarporley toddler who contracted E.coli were also found to have caught the bug.
The two-year-old who caught the dangerous E.coli 0157 infection more than two weeks ago has fully recovered from her illness.
However, it was discovered that her parents and five-year-old sister, who were tested for the infection as a precaution, also carried the infection despite having no symptoms.
The Health Protection Agency has said the parents and sister had been kept off work and school to avoid spreading the serious bug.
This week it has been confirmed the parents of the toddler have had two negative tests for the infection, which means they are clear and allowed to return to work.
The Health Protection Agency is waiting for further test results on the five-year-old.
Hugh Lamont, communications manager for Health Protection Agency North West, said: “The agency is continuing to talk and work with the family to try and establish the cause of the infection which is as yet unknown.
“This is an isolated cluster and there have been no other cases of the infection – and we believe it has been contained.”