There's something rotten in the Big Apple: According to the New York City Department of Health and Mental Hygiene, 31 cases of Legionnaires' disease, a serious respiratory infection similar to pneumonia, have been reported since July 10. Two people have died and the NYC Health Department is trying to figure out how the outbreak started. 

According to the Centers for Disease Control and Prevention (CDC), between 8,000 and 18,000 people are hospitalized every year with Legionnaires’ disease in the United States. In 2012, an outbreak of the disease killed two people at a downtown Chicago hotel, prompting the hotel to drain all of its pools, fountains and hot tubs to check for the Legionella bacteria that cause the disease.

Here's what else you need to know about this sneaky bacteria.

Related: The Down and Dirty On Hot Tubs

What is Legionnaires’ disease?

The Legionella bacterium gets its name from an outbreak during an American Legion convention at a Philadelphia hotel in 1976. More than 130 people were hospitalized for what looked like severe pneumonia and 25 of them died. 

Legionella thrives in plumbing systems with warm water, such as those connected to whirlpool spas, hot tubs, humidifiers, hot water tanks and cooling towers, according to the CDC. In the Philadelphia outbreak, the bacteria spread through the hotel's air conditioning system

People also can get the disease by breathing in the mist that rises from the water in a contaminated hot tub. Legionnaires’ disease is not contagious, however. You can't catch it from another person, according to the NYC Health Department.

Related: CDC Warns of Chlorine-Resistant Parasite

Symptoms and treatment

The symptoms of Legionnaire's disease are similar to other forms of pneumonia. They usually appear from two days to two weeks after exposure to the Legionella bacteria, says the CDC.

Symptoms may include:

  • Cough
  • Shortness of breath
  • High fever
  • Muscle aches
  • Headache
  • Fatigue
  • Loss of appetite
  • Confusion
  • Diarrhea

About 15 out of 100 people who get Legionnaires’ disease will die from the infection, says the CDC. Most other people can be treated with antibiotics. Some will need to be monitored in a hospital. 

The best way to prevent an outbreak of Legionnaire's disease is by cleaning and disinfecting hot tubs, pools and water systems regularly. Of course, the maintenance standards at a hotel or other public property is out of your hands. However, what you can do to protect yourself is not smoke, says the Mayo Clinic. Smoking will increase your chances of getting sick if you're exposed to the Legionella bacterium. 

The CDC adds that besides smokers, others at risk are people with chronic lung disease, weak immune systems, those taking immunosuppressive drugs and folks 50 and over. These people should stay away from hot tubs and other settings where the Legionella bacterium can thrive.

Related: Splash Parks: Keeping Kids Safe in Iffy Waters

Muriel Vega is a writer with a passion for budget travel and staying safe while abroad. A Georgia State University graduate, she has over 6 years of editorial experience and has written for The Guardian, The Atlantic, The Billfold, among other outlets. In her free time, you can find her baking pies, playing with her two dogs and cat, or planning her next vacation. She spends way too much time on Twitter, one of her favorite social media channels. Her favorite safety tip: Make sure you have all the necessary shots before you go abroad.