ORLANDO, Fla. (AP) -- Officials in Florida are investigating two LA Fitness health clubs after four customers contracted Legionnaires' disease.

Kent Donahue, a spokesman for the Florida Department of Health in Orange County, tells the Orlando Sentinel three cases are tied to one club near Orlando, and one is linked to another.

Donahue it isn't certain the individuals contracted the disease at the health clubs. But all four visited the LA Fitness centers and the health department isn't aware of other commonalities in the cases.

The Sentinel reports the health club sent notices to customers last week, warning them to watch for signs of Legionnaires' disease.

Legionnaires' disease is a respiratory illness caused by Legionella bacteria and is typically contracted through water systems or air-conditioning systems.