King County Public Health is investigating the cases of three children all under age 5 who have E. coli infections.

Two of the children had to be hospitalized with complications, including a type of kidney injury. The third is recovering at home.

Health officials don’t yet know whether the children have the same strain of E. coli and whether the cases are linked.

Public Health – Seattle & King County said it received the first report of illness on May 26, the second report on June 1 and the third on June 6.