BLACK RIVER FALLS, Wis. (WSAU) - The Lake Wazee Beach at Black River Falls will stay closed at least through the weekend.

It’s where dozens of people got sick while swimming during the Fourth-of-July holiday – and Jackson County health officials now say the numbers of cases have grown to over 170. The U-S-D-A has been conducting tests of the lake water – but officials are still not sure about the organism that caused the illnesses.

Markers for fecal contaminants have been found to be present in the waters at the beach. Jackson County Health Officer Christine Hovell says those affected have come down with flu-like symptoms such as vomiting, diarrhea, and body aches. She says they normally start to disappear in 24-to-36 hours.

By closing the beach, officials say they hope natural elements like warm temperatures and ultra-violet rays from the sun will destroy the human contaminants in Lake Wazee’s water.