MDH investigators identify 49 illnesses linked to swimming at Minneapolis lake

Disease investigators at the Minnesota Department of Health (MDH) today said they have identified a total of 49 people so far who became ill with diarrhea after swimming at Lake Nokomis. The total includes the three initial lab-confirmed cases of Shiga toxin-producing E. coli (STEC) announced Wednesday.

The cases include both children and adults, with about 20% of cases younger than 10 years old. In all cases, people became ill after swimming at the lake between July 16 and Aug. 11. No one has been hospitalized.

Health officials said it is not unusual to see an increase in the number of cases identified in an outbreak after information circulates and people realize their illness symptoms may be related to the outbreak.

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.