One of Minneapolis’ most popular lakes was shut down Tuesday amid worry that an E. coli outbreak that sickened three children may be more widespread.
Officials indefinitely closed Lake Nokomis’ two popular beaches due to high bacteria levels while the state Department of Health investigates.
All events at the lake, including youth swim lessons and logrolling activities, have been canceled until further notice as officials urged people who use the city’s lakes and wading pools to practice good hygiene.
“This is the first report of people getting ill from swimming in Minneapolis lakes we have had in more than two decades,” Park Board Superintendent Al Bangoura said Tuesday night. “We take this news very seriously and are working closely with the Minnesota Department of Health as they conduct their investigation.”
The children, who are 10 and younger, became ill after swimming at the lake between July 26 and Aug. 1.
Heightened E. coli levels at area lakes have shuttered half the city’s 12 public beaches this summer. But unlike closures at Bde Maka Ska/Lake Calhoun, Lake Wirth and Lake Hiawatha — where bacteria was attributed to large volumes of rain runoff — health experts believe Lake Nokomis was likely contaminated by humans.
Park Board staff members are urging recent swimmers to contact the Health Department if they become sick, saying it’s possible they were exposed and have yet to develop symptoms.
The Minnesota Department of Health identified the strain of bacteria as Shiga toxin-producing E. coli or STEC.
“This strain of E. coli can lead to serious illness,” said Trisha Robinson, the agency’s waterborne disease supervisor. Strains like this are often caused by another ill swimmer, she said.
“We should not be going swimming while we’re sick with diarrhea — and that is often how it [spreads] … just a small amount of fecal material that we all bring into the water with us is, unfortunately, enough to contaminate a beach area and make people sick,” she said.
Although public beaches are regularly monitored, tests cannot detect this specific strain. “It’s not a perfect science,” Robinson said.
Recent tests for E. coli on Lake Nokomis proved well below average, said Deb Pilger, director of environmental management for the Park Board.
“This is highly unusual,” said Pilger, who can’t recall a city beach closure due to illness in her 25 years at the department.
Her recommendations: “If you are swimming in our lakes or wading pools, don’t ingest the water. Wash your hands afterward. Don’t bring dogs in; don’t bring leaky diapers.”
Elevated E. coli readings this summer prompted 11 Twin Cities beaches to close in July. The most prominent sickened 116 people who had been in the water near Lake Minnetonka’s Big Island during the crowded July 4 weekend.
E. coli, or Escherichia coli, is a species of bacteria that normally lives in the intestines of healthy people and animals, according to the Health Department’s website. More than 700 types of E. coli have been identified, most of which are harmless or cause brief diarrhea. A few strains can cause more severe abdominal cramps, bloody diarrhea and vomiting.
Rain can increase bacteria content in lakes by washing lawn fertilizer and animal feces into the water. Boat owners sometimes illegally dump human waste into the water, too — which some believe caused the Big Island contamination.