Health officials are looking into whether a recreational water facility in the Milwaukee area is the cause of at least eight illness caused by cryptosporidium.
Jamie Berg of the North Shore Health Department tells the Milwaukee Journal Sentinel eight cases have been confirmed of the waterborne illness and 12 are suspected in Bayside, Fox Point and Whitefish Bay.
Berg says the investigation has been definitively narrowed to a pool, lake or river. None of the illnesses has required hospitalization.
Berg says the state sees a few Crypto cases each year, but the clustering in this outbreak is not typical.
In 1993, the parasite entered Milwaukee's municipal water supply, leading to the deaths of as many as 100 people and sickening hundreds of thousands more.