I'm worried about Legionnaire's disease

http://www.wsj.com/articles/12-dead-in-nyc-legionnaires-disease-outbreak-1439233064

The recent outbreak of Legionnaire's disease in NYC worries me.  This used to only occur aboard dirty cruise ships with unclean ventilation.  Now, the disease is being found in housing buildings in the Bronx.  I wonder how long it has been since we have cleaned our air conditioning units in the building where I live.  I can only imagine, with horror, what could happen if there was Legionnella bacteria in our air conditioning.