MINNEAPOLIS — Allina Health has notified about 140 patients at two of its Twin Cities hospitals that they may have been exposed to tuberculosis.

The patients were treated at either Abbott Northwestern or Mercy hospitals earlier this year. A worker at each hospital who helped deliver care had active TB.

The Centers for Disease Control and Prevention said TB is an infectious bacterial disease that usually attacks the lungs. It can be spread by an infected person through coughing, sneezing or speaking.

According to a press release, Minnesota Department of Health’s Dr. Raj Mody said TB is actually hard to spread. He said it requires prolonged exposure and not everyone who is infected becomes ill.