The girl — whose identity and hometown have not been released — went to the Saugeen Memorial Hospital in Southampton after falling ill recently.
She returned two days later to get the results of blood work that showed ecoli bacteria and she was rushed to a London hospital.
The Grey Bruce Health Unit doesn’t know the source of the infection.
Medical Officer of Health Doctor Hazel Lynn says they are looking at a family member and possible food — but they are also testing the water outside the family cottage.
