172 sickened in Big Island 4th of July outbreak, cause unclear

State and county health officials say more than 170 people fell ill due to an outbreak at Big Island on Lake Minnetonka on the Fourth of July.

Authorities with Hennepin County Public Health and Minnesota Department of Health gave an update on the investigation at a press conference Friday afternoon. 

While health officials can't identify the exact pathogen behind the illness, they can confirm an outbreak did occur. They say it's possible they may never know the exact cause.

Investigators interviewed more than 200 people and learned more than 172 people experienced symptoms such as vomiting and diarrhea.

They say there is no ongoing threat as the illness is specifically linked to the Fourth of July gathering. Officials report most of the illnesses from Big Island lasted about 24 to 48 hours. While there was a wide age range impacted by the outbreak, on average the victims were in their mid-20s to early 30s.

Health officials are urging people to practice good hygiene habits while visiting the lake, such as not using the lake as a bathroom, washing hands and showering before and after entering the lake.

But the July 4 illness outbreak at Big Island is not keeping Brian Johnson away from the water. “I wouldn't not go out there. It’s nature and nature pretty much takes care of itself -- that's kind of the way I look at it.”

“At this time, we do not believe there is an ongoing heightened risk of disease to the general public on Lake Minnetonka,” explained Dave Johnson, Hennepin County Public Health.

State and county officials believe whatever pathogen spread quickly was likely transferred through the warm, relatively still water in the popular island’s immediate area, perhaps from human fecal contamination.

Despite the outbreak, health officials say it's okay to come out and enjoy the lake. But be smart out on the water: Shower before and after jumping in and try not to swallow any of it. If you’re sick, stay at home, and don’t use the lake as a bathroom.