Updated, 12:02 p.m.

Good morning on this moist Tuesday.

Sixteen New Yorkers around lower Washington Heights had been sickened by Legionnaires’ disease, a severe form of pneumonia, as of Monday night.

The city’s Department of Health and local physicians are monitoring the outbreak closely. Here are answers to a few common questions:

What are the symptoms?

Fever, coughing, shortness of breath, muscle aches, weakness and sometimes, gastrointestinal troubles like diarrhea, said Dr. Marshall Glesby, associate chief of the division of infectious diseases at Weill Cornell Medicine and NewYork-Presbyterian.

It could look a lot like the flu.

Is it contagious?

No.

“It’s not contagious human-to-human,” according to Dr. Demetre Daskalakis, the deputy commissioner of disease control. Legionnaires’ disease comes from inhaling water vapor that contains the Legionella bacteria.

“It’s environmental exposure plus risk,” he added. Those at higher risk include people over 50, tobacco smokers or those with chronic lung disease, and those with weakened immune systems (from diabetes or treatments like chemotherapy, for example).