All of the people, who range from 45 to 75 in age, have been sickened since Sept. 21 in the Morris Park area. None have died, officials said. The sixth case was discovered Friday and triggered an algorithm the city has to detect clusters of the disease.
Three of the infected people live in Morris Park, while the other four either work in the neighborhood or have visited it. None of the cases have been traced to the same building.
Additionally, all of the patients have had underlying medical conditions that put them at risk for contracting the disease, Health Department Deputy Commissioner Dr. Jay Varma said in a conference call.
All of those affected are currently hospitalized and receiving treatment, Mayor Bill de Blasio said Monday at a City Hall press conference.
"Thank God all are getting treatment, there have been no deaths in this situation," de Blasio said.
The current cluster is not related to the outbreak over the summer, which started in the Opera House Hotel cooling tower, killing 12 people and sickening more than 120, and the city's water is still safe to use, according to the Health Department.
"Because we identified this as a cluster doesn't mean that we know what the cause is of these infections in these individuals, but they are geographically linked," Health Commissioner Dr. Mary Bassett said at City Hall Monday.
She urged New Yorkers to seek treatment for flu-like symptoms such as fever, chills, body-ache, headache and difficulty breathing. The city is also reaching out to the community’s vulnerable population to make sure they understand the symptoms of the disease.
Bassett said all 35 cooling towers in the neighborhood were tested to try and identify the source of the outbreak. The towers had recently been cleaned due to the order Bassett issued during the South Bronx outbreak of the disease.
Building owners were required to register their cooling towers with the city in accordance with recently passed legislation responding to this summer's outbreak of Legionnaires' disease in the South Bronx, and this information was extremely helpful when figuring out which buildings to test in Morris Park, according to Varma.
"The new legislation made it possible for us to immediately identify all the buildings in the surrounding area that have cooling towers and then to send teams out on Saturday and Sunday to sample from those cooling towers," he said.
The city is still trying to determine the source of this Legionnaires' disease cluster, and Varma stressed that it was possible the seven different cases had stemmed from seven different places.
"We don’t have enough information to say conclusively that there is a single source for all seven of these infections," he said.
The city normally investigates between two and 10 clusters of Legionnaires' disease each year, and since the year 2000, there has been a steady increase of cases reported throughout New York City and across the country, Varma said.
He attributed this partially to more aggressive investigations into the disease.
"Any time you look more for something, of course you may be more likely to find it," he said.
Bronx Borough President Ruben Diaz Jr. said that his office had been in contact with city, state and federal officials about the Legionnaires' disease outbreak and would continue to keep an eye on the impacted area.
"As we monitor this situation, we urge anyone who feels sick to visit their doctor or a hospital to get checked," he said. "It is too important to wait.”