City health officials are investigating an outbreak of Legionnaires' Disease that has killed two people in the South Bronx. NY1's Erin Clarke filed the following report.

For the second time this year, officials are warning about an outbreak of Legionnaires' Disease. And like the first outbreak, this one affects the Bronx. 

"We know the particular area of concern is the South Bronx," said Mayor Bill de Blasio.

"The first case identified at this moment was on July 10, and since then, we have identified 31 cases," said Health Commissioner Dr. Mary Bassett.

Sources tell NY1 that the new outbreak involves at least four neighborhoods: Highbridge, Morrisania, Hunts Point and Mott Haven. Officials declined to say where the two people who died lived.

Back in December and January, 12 people were diagnosed in the Bronx, eight of them in Co-op City. Testing found the bacteria that causes the disease in a tower holding water to cool Co-op City's heating and electrical systems.

"Well, I was really afraid when it happened in Co-op City cause I was in the section of three and I was in section 2, which was quite close," said one resident. "I thought it was wild."

That time, though, everyone survived.

The latest outbreak has borough residents worried.

Clarke: Does it scare you to hear something like this?
Person in Bronx: Definitely. I'm in the Bronx. I work here. I drink water here. So if it's in some kind of water or food, we need to know.

City officials, though, stress that there is no need to worry, as long as people seek treatment.

The principal symptoms are fever, cough, chills and muscle ache.

"I want to make clear that this is a common pneumonia, one which, as the mayor said, is readily treated, especially important for people to seek care early and especially important for health care providers to be aware that we're seeing these cases," Bassett said.

Right now, the Department of Health is testing water from cooling towers and other potential sites where the Legionnaires' bacteria may be hoping to determine the source of the outbreak.

"We have our disease detectives out in the field scanning the environment and looking for places to take samples," Bassett said. "Samples are already being taken."