Legionnaires Outbreak in South Bronx.
BOLDUAN: Happening now, an outbreak of Legionnaires' disease has taken more lives in New York City. Seven people have now died from the bacterial infection. More than 64 people have been hospitalized.</s>BERMAN: All the victims are from the south Bronx. Officials have traced the likely cause of the outbreak, the maintenance cooling towers, or I should say, the location of he outbreak, the maintenance cooling towers, which tested positive for the bacteria. CNN medical analyst, Dr. Seema Yasmin, joins us now. Seema, we hear about these outbreaks from time to time at hospitals or places like this. How do you catch, how do you get Legionnaires' disease.</s>DR. SEEMA YASMIN, CNN MEDICAL ANALYST: The most important thing to know is it's not spread from person to person, but it is spread through microscopic water droplets. This bug absolutely loves water. So often times, in outbreaks like this, we'll trace the source back to things like hot tubs, showers, faucets, air conditioning systems, and like in this outbreak now, to water cooling systems.</s>BOLDUAN: There also -- it appears that the country has seen an increase in Legionnaires' in recent years. What's attributed to that?</s>YASMIN: That's absolutely right. We've seen probably a tripling of cases in the last 10 years or so. Used to be we'd see about 1,000 to 2,000 cases a year. Now the CDC says we're seeing 8,000 to 18,000 cases every year. And they're saying it could be one of two things. One is that we're just catching the disease more. So now when somebody has pneumonia, we're not just saying you have a typical pneumonia. We're testing to find out what bug is causing it. But the second reason is we're seeing a booming population of older adults, and those are the people who are most at risk. People over the age of 55, people who smoke, people who already have a pre-existing lung disease, and also anyone with a weakened immune system.</s>BERMAN: And how do you stop an outbreak like this? How do you get rid of it once it's around?</s>YASMIN: The most important thing you do is find the source of the outbreak.