MADISON, Wis. (AP) _ The widespread flooding across much of southern Wisconsin this month is suspected of causing the severe illness of a 6-year-old boy from Richland Center.

He's been on kidney dialysis and in intensive care since Sunday at the University of Wisconsin Hospital in Madison, and doctors say he probably will be in the hospital at least a week.

The doctors suspect he's got a hard-to-detect strain of E. coli bacteria, although a test for a potentially deadly form of it came out negative.

Dr. Ellen Wald says the boy started vomiting three days after he played in a flooded creek near his home.

Authorities have warned repeatedly that flood water may be contaminated by bacteria because sewage plants were overwhelmed during the storms.

State officials say more than 160 communities have discharged untreated sewage into streams and lakes because flooding shut down their treatment systems. The releases totaled more than 800 million gallons of sewage.