OSHKOSH, WI (WTAQ) - Health officials in Winnebago County are warning people swimming in Lake Winnebago.

Several cases of a strain of E. coli illness was reported among people who were swimming in the area of "The Streichs," a popular sandbar on the lake's west shore just north of Streich Lane in the Town of Black Wolf during the July 4th holiday.

According to the health department, E. coli infections can cause stomach cramps, diarrhea, vomiting and mild fever. Most people recover in about a week, but some infections can be life-threatening.

Health officials say swimmers should be aware of shallow and stagnant areas, which can pose higher risks. Swimmers should be careful not to get any lake water in their mouths. Children who might accidentally swallow lake water should not be allowed to swim in the lake. Officials say swimmers should also avoid using the lake as a toilet and wash their hands thoroughly after going to the bathroom. Boaters should also not dispose of any human waste in recreational waterways.

The danger of E. coli is just the latest to be associated with the lake. Blue-green algae, which can make people and animals sick, has already been reported in the lake.