July 19, 2013
Three E. coli illnesses linked to swimming in Lake Minnetonka
State officials say cases demonstrate important reminder to practice healthy swimming steps when swimming in any lake
State health officials have identified three cases of E. coli O157:H7 illness in Minnesotans linked to swimming in the Big Island area of Lake Minnetonka.
Routine reportable disease monitoring by state health officials identified three cases of E. coli O157:H7 infection with the same DNA fingerprint. The illnesses occurred in young adults, and all are residents of the seven-county metropolitan area. One of the cases was hospitalized but has since recovered. All of the cases reported swimming and boating on July 4 in the Big Island area of Lake Minnetonka, where numerous boaters are known to gather.
The source of the E. coli in the water is unknown. However, lakes can be contaminated through multiple methods, including animal waste, individual septic systems or sewage spills, improper boat waste disposal or ill swimmers. People who swim when they are ill can easily contaminate the water - even if they don't have a fecal accident.
"Swimming in Minnesota's lakes is a very fun and healthy summertime activity, but it also can be a source of illness," said Trisha Robinson, an epidemiologist specializing in waterborne diseases with the Minnesota Department of Health (MDH). "This is the first waterborne outbreak of the summer and illustrates why it is so important that people take steps to prevent infection. If swimmers can follow some basic precautions, hopefully we can prevent more outbreaks at other swimming locations."
The best way to prevent recreational water illnesses is to keep germs out of the water in the first place. Swimmers can take an active role in protecting themselves and other swimmers by following these simple steps for a healthy swimming experience while swimming in any lake:
- Don't swim when you have diarrhea.
- Don't swallow lake water.
- Practice good hygiene. Shower with soap before swimming.
- Wash your hands thoroughly after using the toilet or changing diapers.
- Take children on bathroom breaks or change diapers often.
- Change diapers in a bathroom, not at beachside.
Symptoms of E. coli O157:H7 illness typically include stomach cramps and diarrhea, often with bloody stools, but little or no fever. People typically become ill two to five days after swimming in contaminated water. Most people recover in five to 10 days. However, E. coli O157:H7 infection sometimes leads to a serious complication called hemolytic uremic syndrome (HUS), which can cause kidney failure and other severe problems, including death. HUS can occur a week or more after the onset of diarrhea. Those most at risk of developing complications from E. coli include the very young, the elderly and those with weakened immune systems.
E. coli O157:H7 infections should not be treated with antibiotics, which might promote the development of HUS. More information on E. coli O157:H7 can be found at http://www.health.state.mn.us/divs/idepc/diseases/ecoli/index.html.
Anyone who believes they may have developed E. coli should contact their health care provider.
All public beaches on Lake Minnetonka remain open and have passed their regular water quality monitoring tests. Those results can be followed at http://www.hennepin.us/beaches.