Worst of NYC Legionnaire’s Outbreak Is Over

The Bronx is in the midst of the worst outbreak of Legionnaire’s disease in New York City history. Legionnaire’s, a bacterial infection that can cause severe pneumonia and death, has been diagnosed in 86 people thus far, killing seven.

Both cases and fatalities surely will rise in the days ahead given the long—usually 10 days but up to 20—incubation period of the disease. That said, it is likely the worst of it is over, as the frequency of new cases has begun to drop—and a local hotel caught up n the outbreak has declared itself safe and open for business.

The cause of the outbreak is uncertain, as is often the case when Legionnaire’s occurs across a city as opposed to a single building like a hospital or hotel. To date, New York City public health officials have found the bacteria in five of 17 tested cooling towers (not to be confused with wooden water tanks—see below), a place that legionella, the bacteria that causes Legionnaire’s disease, is known to thrive.

Whether those five are indeed the smoking towers is uncertain. Legionella can be found in water in small amounts and, we haven’t yet been told about the concentration of bacteria from the towers. A high concentration would point the finger very strongly at these as the source whereas a little here and a little there might just be background noise and not the cause of the Bronx tragedy.

Surely though, water is the problem: The disease was described 40 years ago during a convention in Philadelphia of 2,000 Legionnaires, mostly older male war veterans who for decades had gathered periodically to reflect and reminisce. Many became deathly ill with pneumonia after exposure to a contaminated water-cooling system at the now-razed Bellevue-Stratford Hotel. Then as now, the fatal cases occurred mostly in those with underlying conditions such as lung disease.

There have been dozens of outbreaks since, including one 25 years ago related to a water sprayer used to freshen fruit and vegetables at a Winn-Dixie grocery store in Louisiana. Though unusual among outbreaks, the Winn-Dixie story demonstrates just how legionella gets from here to there. Legionella is an unusual bug among respiratory infections—we get infected not from each other’s coughs or sneezes but by aspirating the bacteria from the environment into our lungs. This means it can come off the showerhead or the fruit sprayer or the fine mist the surrounds cooling towers.

But like many issues in medicine, there are several different theories regarding just how legionella gets into the air. Everyone agrees that the disease is not spread person to person and all concur that contaminated mists of water are the problem. But how and where the mist is generated continues to rankle and divide.

On one side stand the water tank people. The water tank is that enormous 19th-century wooden structure sitting barrel-like atop apartment roofs. Rainwater or municipal water collects there and flows downhill into faucets and showerheads where it can then spray into the air and lungs.

The cooling tower people though scoff at the notion—and as mentioned, cooling tower contamination is considered by the expert group at the New York City Department of Health to be the source of infection. Cooling towers are difficult to describe, though if you grew up in the suburbs you probably crouched behind one—a large square noisy box placed onto a concrete base—while playing hide-and-go-seek. In a cooling tower, water is used not to drink or shower, but rather to absorb heat exhausted out of the building. The newly heated water then naturally evaporates—mostly. Some may spread downwind in a mist, where an unsuspecting pedestrian may inhale it.

The good news is that the fix for problems in the water tank or in the cooling tower is the same: “remediation,” a high-end word for killing the resident bacteria. It’s easier said than done—legionella, like some other bacteria, survives in warm water—and it loves the slime. It lives in the biofilm, that snot-like goo that grows on the inside sleeve of pipes and barrels. Biofilm, a complex ecosystem of increasing scientific inquiry, affords the legionella a safe haven away from most chemicals that might kill it.

The answer is a hodge-podge of possible remedies well turned by hospitals and cruise ships, which fight hard every day to keep the bacteria out. Some add copper and silver ions to the water supply in minute amounts, a trick that seems to zap legionella very efficiently. Others use pulses of chlorine through the water system while still others try to scald the bacteria to death by running 160-degree water through the pipes.

The remedy for the Bronx is well-known—more regulation to make sure all those cooling towers and all those water tanks are inspected and cleaned and kept as sparkling as the same equipment in hospitals and cruise ships.

No surprises at all, though the notion of creating yet another inspector with another checklist followed by another cottage industry of copper-silver zappers and all the rest surely can give a person pause. Such lumbering, unglamorous, only modestly effective interventions however comprise the central role of government—protecting the public’s health as best it can.