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.

Undetectable strain

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.