There's a reason that parts of the South Bronx have been dubbed Asthma Alley. It's where 17 percent of kids are afflicted with the respiratory ailment, giving that corner of the New York City borough one of the highest rates in the country. Asthma-related deaths there are three times the national average. While those statistics may appear to have little to do with the ongoing outbreak there of a different disease, Legionnaires’, the overlap is hardly coincidental.

The core of the recent deadly outbreak of Legionnaires’ disease has been centered in the South Bronx, the "poorest urban county" in the U.S. already struggling with higher-than-average levels of health disorders that aside from asthma include diabetes. Unlike those chronic diseases, however, Legionnaires’ is caused by bacteria. But the social and environmental factors in the South Bronx place it at particular risk of being disproportionately affected by an outbreak in a manner that more affluent neighborhoods are not, public health experts and officials said.

“We do have a unique set of challenges that is deep-rooted, unfortunately, in our community,” State Sen. José Serrano, a Democrat whose district includes the South Bronx, said in an interview. “The health disparities are real, and they’re going to compound the pain of Legionnaires' in the community,” he said.

Twelve people have died in an outbreak of Legionnaires’ disease in the South Bronx that dates back to July 10, at least 113 have been sickened in New York City and dozens have been hospitalized because of it, according to officials. It’s the largest outbreak of the disease in the state’s history. Cooling towers used for air conditioning in large buildings like hospitals and schools are the suspected culprit, spraying water droplets contaminated with Legionella bacteria that can sicken those who inhale it.

New York City buildings with cooling towers would undergo a vigorous two-week inspection to disinfect them, Dr. Mary Bassett, the city's health commissioner, announced last Thursday. Public health bodies, from the Centers for Disease Control and Prevention to the New York State Department of Health, previously have issued guidelines for preventing bacteria from spreading, but until now, no formal testing requirements have been mandated for the city’s thousands of cooling towers.

As of Monday, 11 sites had tested positive for Legionella bacteria, the New York City Department of Health said. The vast majority of them were in the South Bronx. Mayor Bill de Blasio and New York Gov. Andrew Cuomo also announced emergency regulations Tuesday that included requirements for maintaining cooling towers.

Three cases of Legionnaires’ disease also have been reported in Rockland County, north of Manhattan and along the Hudson River, although a spokesman for the county said only one was related to the outbreak in the Bronx. 

A Potent Mix

Legionnaires’ disease in New York City grew 230 percent from 2002 to 2009, researchers found in a study for the city’s health department published in November. They pointed out that the elderly and people who smoked or had chronic obstructive pulmonary disease or diabetes were at greater risk of contracting the disease. Of the 12 people who have died in the current outbreak, all but one were over 40 years old and all of them had pre-existing health issues.

However, the researchers found other factors that seemed to increase the likelihood of catching Legionnaires'.

Areas with the highest rates of poverty had an average of three cases of Legionnaires' disease per 100,000 people every year, the study found. In low-poverty areas, the rate dropped to 1.2 out of 100,000 people. “Our findings suggest systemic differences in the risk for acquiring Legionella infection based on neighborhood-level poverty; these socioeconomic disparities in disease should be of concern to public health policy makers,” the researchers said.

“If environmental issues in high-poverty neighborhoods contribute to the disparity, greater effort may be warranted, for example, on the upkeep of cooling towers and water systems in the buildings in these areas,” the researchers added presciently. That was nearly one year ago.

“In the South Bronx, you have a high concentration of people who have underlying health conditions,” Serrano, the New York state senator, said. Those people also face challenges accessing medical care. When those existing problems are coupled with an outbreak of Legionella bacteria, “you create this cauldron of something potentially bad,” he said.

A Question Of Affluence

Aggravating the situation are questions of funding and resources, both public and private, which vary significantly by New York City neighborhood. In 2012, the South Bronx was named the poorest congressional district in the country, with nearly a third of residents living below the federal poverty line. Reports of underfunded schools, affordable housing programsparks and even an animal shelter in the Bronx are frequent. 

Legionella bacteria are fairly endemic and can be found in the natural environment, Dr. Ann Kurth, associate dean for research at the Global Institute for Public Health at New York University and a professor at its College of Nursing, pointed out. But under the right circumstances, they can proliferate into a public health hazard.

“There are several conditions needed for [Legionella] to aerosolize and then infect and cause disease,” Kurth noted. Buildings in affluent neighborhoods that are not only well-managed but also have resources at their disposal will be more able to take prophylactic measures and prevent bacteria from breeding in water systems and cooling towers, she said. In poorer areas, she said, if buildings have fewer resources to take preventive measures, the risk of bacteria growing is likely to be higher.

Legionnaires' outbreaks have occurred sporadically, but none have been as lethal as the current one. In January, a cooling tower at Co-op City, in the Baychester section of the Bronx, was found to have Legionella bacteria. Eight people were confirmed to have Legionnaires' disease, although no one died. Legionella also was found in Co-op City in 2012 and 2013. Three patients at a hospital in New Brunswick, New Jersey, also died from the disease in 2008.


Other experts echoed the idea that the level of infrastructure maintenance plays a role in the spread of the bacteria and that the wealth of a neighborhood can influence the health of its residents. “Some buildings are more likely to be better maintained than others,” Stephen Morse, a professor at the Mailman School of Public Health at Columbia University, said.

"The quality of inspections and the compliance with their recommendations is probably not nearly as high in the South Bronx as it is on the Upper East Side," Dr. Victor Rodwin, a professor of health policy at the Wagner School of Public Service at New York University, said. "The incidence of disease is generally much higher among those on the lower end of the income spectrum."

Health officials have targeted the cooling towers as the suspected cause of the outbreak, but they have yet to determine exactly how it began, or why the South Bronx has been at the heart of it. Many key questions remain.

“Why all of sudden are we having this major cluster? What’s different about the bacteria? What’s different about the way that we operate cooling towers?” State Sen. Serrano said. “I think everything should be on the table to figure out what created this.”