What to Know About New York’s Legionnaires’ Disease Outbreak

Nearly 60 people have become sick and two have died in an outbreak of Legionnaires’ disease in New York City. Health officials there issued an alert on July 30 warning residents of Central Harlem who have flu-like symptoms to see a health care provider immediately.

Legionnaires’ disease is a form of pneumonia caused by the bacteria Legionella. (The bacteria and the disease get their name from the first outbreak at an American Legion convention in Philadelphia in 1976.) The bacteria tend to grow in water, including cooling towers that service buildings in the summer, as well as air conditioning systems, hot tubs, and decorative water displays like fountains. About 6,000 cases are reported in the U.S. each year, and about 200 to 800 of these occur in New York City.

The likely sources of the current outbreak are cooling towers, the New York City Health Department said on Aug. 4, which helps to control the temperature of cooling systems like refrigeration and air conditioning. The tower sprays mist, which can contain the bacteria that people then inhale. So far, the city has detected Legionella in 11 of the towers. The biggest danger is to people who might have been exposed to and inhaled the mist.”It is safe for you to drink water, bathe, shower, cook, and use your air conditioner,” city health officials said in the alert.

Here’s what to know about the disease.

What are the symptoms of Legionnaires’ disease?

People exposed to the bacteria generally start showing symptoms two to 14 days later. These are very similar to symptoms for pneumonia, including fever, cough, headaches, and shortness of breath. Some people also have diarrhea or nausea and can show signs of confusion.

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How would I know if I have Legionnaires’?

Because the symptoms are similar to those for the flu, most doctors won’t test for the bacteria. But in areas where cases have been reported, such as Harlem, doctors may be more likely to suspect Legionnaires’ and can test to distinguish it from pneumonia. They may start with a chest X-ray, to confirm a type of pneumonia, and then move on to more detailed testing with a urine or spit sample to detect the bacteria.

What causes outbreaks of Legionnaires’?

Because the bacteria live in water, any water source can harbor the germs. That includes natural bodies of water like creeks and lakes, as well as cooling towers, fountains, humidifiers or misters, hot tubs, and even the tanks that hold windshield wiper fluid in cars.

Warmer temperatures between 77°F and 113°F can help the bacteria reproduce, according to the U.S. Centers for Disease Control and Prevention (CDC), especially in man-made water systems.

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The CDC provides guidance on how building operators can guard against outbreaks, by monitoring water and using disinfectants like chlorine in other potable water systems. Maintaining proper pH of the water to ensure the disinfectants are effective is also critical.

People can get infected by coming into contact with the bacteria from one of these sources; the bacteria commonly spread in particles as fine as water mist or vapor.

Is Legionnaires’ contagious?

No, the bacteria does not spread from person to person.

Are there treatments for Legionnaires’?

There is no vaccine, but certain antibiotics can treat the infection. Not everyone who is exposed will get sick, but people who are older and those with weakened immune systems are more likely to experience symptoms and may even require hospitalization if breathing becomes difficult. According to the CDC, about one in 10 people who get Legionnaires’ will die from complications of the disease.