Minnesota’s Lake Nokomis is to blame for more illnesses that might be caused by Shiga toxin-producing E. coli, which is frequently a foodborne pathogen.

E. coli is a type of fecal coliform bacteria commonly found in the intestines of humans and animals.  E. coli in recreational waters are usually less threatening strains that can make people sick but typically are not deadly.

It is E. coli O157: H7 and other harmful strains pose more significant dangers to human health.

Disease investigators at the Minnesota Department of Health (MDH), in recent days, expressed concern about 49 people who were ill with diarrheal symptoms after swimming at Lake Nokomis. At least 20 more Lake Nokomis swimmers are now among the sick, raising the total to 69.

The Minneapolis Department of Parks and Recreation owns Lake Nokomis. It has two public beaches, one on the northwest side and the other on the northeast side. A restaurant, concessions, indoor restrooms, and a variety of rental equipment, along with a playground are located on the northwest beach. Portable toilets are on the northeast side.

Shiga toxin-producing E. coli (STEC) in three initial cases are lab-/confirm/ied, according to MDP.

The patients include both children and adults, with about 20 percent of cases younger than ten years old. In all cases, people became ill after swimming at the lake between July 16 and Aug. 11.

No one has been hospitalized.

It is not unusual to see an increase in the number of cases identified in an outbreak after information circulates because people realize their illness symptoms may be related to the outbreak, health officials say.

Most of the new cases were identified through responses to a survey sent by MDH to groups of swimmers known to have used the beaches from mid-July through mid-August.

Minneapolis Park and Recreation Board (MPRB) officials said the Nokomis beaches will remain closed for the rest of the swimming season out of an abundance of caution.

Health officials said they would need to see no illnesses reported for at least 16 days (two incubation periods of 8 days) before they could say there was no longer a risk of STEC spreading through water at the beaches.

Anyone who is experiencing symptoms of STEC infection – diarrhea (often bloody), stomach cramps, no or low-grade fever – should see a health care provider.

The MDH and MPRB are asking anyone who visited Lake Nokomis from mid-July through mid-August to complete a brief MDH online survey.

The MPRB reminds the public that there are currently seven beaches open through Labor Day, with the closest two beaches located at Lake Harriet.

There are also dozens of pools open, with nearby wading pools located at Lake Hiawatha, Bossen and Keewaydin wading pools.

However, health officials remind all Minnesotans that anyone who has diarrhea should not go swimming in any body of water.