Four people in the Bangor area have been hospitalized for a type of pneumonia known as Legionnaires' disease.
The Maine CDC says it's investigating whether the cases are connected. The agency has also alerted health care providers to consider testing for the disease to identify more cases.
Legionnaires' disease is caused by the Legionella bacteria, which is found naturally in freshwater, such as lakes and streams. It can become a health concern when it grows in human-made water systems such as air conditioning, hot tubs, and fountains. Cases have been on the rise in the U.S. and Maine averages about 20 cases a year.
Symptoms include shortness of breath, cough, fever and aches.
