MINNEAPOLIS — Health officials have closed all beaches at a popular Minneapolis lake after number of illnesses identified in people who swam there rose to 49.

All of the diarrhea cases involve people who became ill after swimming at Lake Nokomis since mid-July. The Minnesota Department of Health reported the jump in cases Friday.

The 49 cases include the three original laboratory confirmed cases of E. coli announced Wednesday. Health officials say it’s not unusual to see such an increase after information circulates and people realize their symptoms may be related to the outbreak.

No one has been hospitalized. The cases include both children and adults, with about 20% younger than 10 years old.

The Minneapolis park board said Nokomis beaches will remain closed for the rest of the swimming season.