4 UW Hospital patients diagnosed with Legionnaires' disease

MADISON — Officials at UW Hospital say four hospital patients have developed Legionnaires' disease.

The patients tested positive for the disease in the past 10 days. The hospital is conducting tests to determine if the bacterium is related to the hospital's water system.

Legionnaires' disease is caused by bacteria typically present at low concentrations in tap water. UW Hospital uses a water treatment system designed to keep levels low, but officials say a recent adjustment to that system may have compromised its function.

UW Hospital says the risk comes only from hot water in the form of airborne droplets, such as water from a hot shower. Cold tap water poses no risk.

The Wisconsin State Journal reports officials have stopped all use of hospital showers. That is expected to continue until Thursday.