Escherichia coli O121 has stricken 10 people — seven children between ages 2 and 6, a nurse and two parents — at an officially authorized childcare facility in Naha.

According to the Okinawa Prefectural Office, after a 20-year-old nurse complained of symptoms including diarrhea, slight fever and stomachache, the cause was identified on Sep. 10 as the O121. A 4-year-old boy was confirmed of having the infection next to the nurse, and eventually 10 people developed the infection by of Oct. 2.