Laboratory tests determined that the Legionella strain found in the Opera House Hotel's cooling tower matched the strain found in patients, the New York City Health Department announced in a news release
"We eliminated the danger posed by the Opera House Hotel's cooling tower as soon as it tested positive for disease-causing Legionella," said New York City Health Commissioner Mary Bassett.
"Today, all cooling towers in the affected area have been disinfected, and all cooling towers across the city are being evaluated and disinfected if necessary."
Epidemiologic and environmental investigations support the conclusion that the hotel's cooling tower was the source of the outbreak, the Health Department said.
As of Wednesday, 12 people in the Bronx had died in the outbreak, and there have been 119 reported individuals with the disease, according to city data. All of the deceased individuals were adults with underlying medical conditions.
There have been no new cases with Legionnaires' disease symptoms after August 3, hence the decision Thursday to declare the outbreak over.
Thousands of Legionnaires' cases each year
Legionnaires' disease, of course, is nothing new, and there's certainly no guarantee it won't return somewhere else.
The bacteria that causes it is found naturally in the environment, usually in warm water, according to the Centers for Disease Control and Prevention
. That makes hot tubs, large plumbing systems, decorative fountains, hot water tanks and -- as was the case in the Bronx -- cooling towers common places for it to originate.
It doesn't spread from person-to-person but rather through the air, as someone breathes in mist or vapor that contains the Legionella bacteria.
Those who get it, typically come down with a fever, chills and a cough. Most recover, but between 5% to 30% of those who get the disease die, according to the CDC. An estimated 8,000 to 18,000 hospitalized cases of Legionaires' occurs each year in the United States.
The disease got its name from a particularly deadly 1976 outbreak in Philadelphia that largely affected people attending an American Legion convention.
An outbreak of the disease killed two people at a hotel in downtown Chicago in 2012. New York's more recent outbreak, which started in mid-July, proved far deadlier.
And the city is trying to do something to prevent a repeat, at least on this scale.
Bassett said "historic legislation passed by the City Council and signed by Mayor de Blasio should help prevent tragic outbreaks like this from occurring again."