Legionnaires’ disease is currently resurging in New York City. This latest outbreak is located in the Upper East Side neighborhood of Manhattan. The first two cases were reported on July 2. By July 10, city health officials reported that 31 buildings had tested positive for Legionella bacteria, which causes the disease. As of July 13, the number of confirmed cases had risen to 59, with 48 hospitalizations and no fatalities so far.

The disease, first identified in 1976 during an outbreak at a Pennsylvania American Legion convention in Philadelphia, is an ongoing problem in New York City, which has an unusually high chronic case rate. Approximately 200 to 700 people are diagnosed with the disease annually in the city, most of whom require hospitalization, with roughly a dozen resulting in death. The last outbreak occurred only a year ago in the city’s Harlem neighborhood. According to the New York City Health Department, there were 114 confirmed cases, 90 hospitalizations and 7 deaths. In 2015 in the South Bronx there were 138 reported infections and 16 deaths. A total of 257 cases were diagnosed in 2024.

Legionnaires’ disease is a severe form of pneumonia caused by inhaling water droplets spread from building cooling towers containing Legionella bacteria. It is not known to spread from person to person. The people at highest risk include adults over 50, smokers and those with chronic lung disease or weakened immune systems. Incubation period is 2-14 days following inhalation. On average, about 5,000 to 8,500 cases of Legionnaires’ disease are diagnosed in the US each year.

It is not restricted to the US. Since 1981, confirmed outbreaks have been reported in the Netherlands, Australia, Spain, England, France and Canada. Most have been associated with cooling towers.

The disease is caused by the Legionella bacterium, which grows in warm, stagnant water. While the bacterium is present in nature, certain man-made environments are especially conducive to its proliferation. The primary known source of infection is water vapor emanating from rooftop cooling towers associated with large building cooling systems. The bacterium can be carried long distances in the water droplets released by the towers, which, when inhaled, may cause disease. There are about 5,000 cooling towers in New York City.

Prior studies have shown that many outbreaks occur in lower-income neighborhoods, where building maintenance is often inadequate. That was the case last year, in the outbreak that was centered in Harlem. This year, the center of infection is in Manhattan’s Upper East Side, a wealthier area. Based on the latest available information, so far the cooling towers of 183 buildings have been tested and 31 have been found positive for the bacterium. One of these is the Guggenheim Museum.

As the Upper East Side outbreak was under way, a building on the Upper West Side was also found to test positive for Legionella. A connection between the two areas has not been established. Unlike the eastern location, the contamination in the west side building was discovered in the hot water system.

It was reported during last year’s outbreak that although the city formally requires landlords to test for Legionella bacteria every three months, compliance and regulatory oversight fell far short of that goal. The city’s Department of Health and Mental Hygiene cited a staffing shortage for the insufficient surveillance. Available information indicates that key roles such as water ecologists and engineers were understaffed. The city has recently hired 23 additional water ecologists and mandated monthly testing rather than quarterly. The problem of compliance by building owners remains unaddressed.

In response to the latest outbreak, City Council Speaker Julie Menin sent a letter to city Health Commissioner Dr. Alister Martin expressing deep concern “that the Department of Health and Mental Hygiene has still failed to require building owners to proactively disinfect all cooling towers in the area under investigation.”

Under the preexisting policy, the city only required landlords to add more chemical disinfectants to towers that tested positive. In response to the latest outbreak, the administration of Mayor Zohran Mamdani will now require affected towers to be drained, cleaned and disinfected. This remains a reactive rather than a proactive approach—responding only after infection has set in—rather than systematically cleaning systems to reduce bacterial growth.

Reporting based on city inspection records found that many cooling towers in the outbreak area had prior violations, including failures to perform required monitoring and maintenance, collect Legionella samples, or submit test results to the Health Department. Some buildings reportedly had no Legionella test results on file for the preceding year, despite legal requirements. The discovery of widespread pre-existing compliance violations has raised questions about how consistently those requirements were being enforced before the outbreak emerged.

The repeated outbreaks of Legionnaire’s disease demonstrate that the policy of leaving it up to landlords to do the periodic testing is akin to having the fox guard the henhouse. A combination of negligence, greed and a lack of serious consequences mean that building owners can ignore the requirement for testing with relative impunity. The repeated and predictable death toll from this disease, coupled with the failure to systematically enforce even the existing, inadequate regulations, indicate that the death toll is considered a “cost of doing business” under capitalism.

Mayor Mamdani’s response so far has included a few positive steps. However, the main issue is the widespread lack of compliance with preexisting testing and disinfection requirements. His record so far in backing down on campaign promises such as taxing the rich strongly indicates that effective enforcement of his stated health policies against the city’s rich and powerful real estate oligarchs cannot be expected. The track record of his two Democratic predecessors indicates that the interests of the ruling class will prevail.

Two mayors were in office in New York City during the COVID-19 pandemic: Bill de Blasio (through December 2021) and Eric Adams (from January 2022 onward). Both are Democrats, and both subordinated public health to the interests of Wall Street and corporate profit. They emphasized back-to-school and back-to-work policies, to revive the “economy” (that is, profit-making).

Given that global warming is increasing the climatic conditions that promote bacterial growth in the cooling towers, it is to be expected that outbreaks will become even more frequent and widespread. Consequently, a more proactive, systematic schedule of thorough cleaning for all such towers would seem prudent. However, no such change has been announced. In a city where a significant portion of the ruling elite consists of those involved in the real estate business, there will be significant resistance to any proposal that would increase costs to building owners.

Cyclosporiasis

Also this summer, an outbreak of Cyclosporiasis, a parasitic infection which causes, among other symptoms, stomach cramps, nausea, vomiting and severe diarrhea, has been reported to the Centers for Disease Control and Prevention (CDC). Several thousand cases have been reported in 31 states, with the majority in New York, Texas, Illinois and Michigan. At least 86 people have been hospitalized, but fortunately no deaths have been reported so far. As of July 10, New York City had reported 372 cases.

Historically, outbreaks have been most common during the spring and summer months. In the past, the disease has been associated with the eating of fresh produce, including basil, cilantro, spinach and berries.

This year’s outbreak is unusual both in the large number of people affected and the delay in identifying a source. Late Thursday the Food and Drug Administration said that it was focusing on iceberg lettuce supplied by Taylor Farms, the largest US producer, to the Taco Bell restaurant chain as the likely source in at least five Midwest states, including Michigan, where the majority of cases have been detected.

Transmission of the disease occurs via food and water contaminated with feces. Spread by direct human to human contact has not been documented. This medium of transmission suggests a failure to maintain high safety and health standards in food production and distribution. Again, an emphasis on maximization of profits by cutting costs is the likely cause, increasingly compounded by the effects of climate change.