HIGHBRIDGE, the Bronx (PIX11) — Four people have been diagnosed with Legionnaires’ disease in a neighborhood in the Bronx since May 9, health officials announced Friday.

New York City’s health department is investigating the source of the cluster in the Highbridge neighborhood (ZIP codes 10452 and 10456) and bordering communities.

Legionnaires’ disease is not contagious and can be treated with antibiotics when caught early. However, the disease can be fatal for people who are considered high risk. No one from these recent cases has died, officials said.

Legionnaires’ disease is a type of pneumonia that is caught by breathing in water vapor that contains Legionella bacteria. Legionnaires’ disease causes flu-like symptoms.

Those at high risk include people who are 50 years or older, smoke, have a chronic lung disease, have a weakened immune system, or take medicines that weaken their immune system.

Legionnaires’ disease symptoms include fever, chills, muscle aches, headaches, fatigue, loss of appetite, confusion and diarrhea. People living or working in the Highbridge area who are experiencing these symptoms should seek medical attention, health officials said.

Most cases of Legionnaires’ disease can be traced to plumbing systems where conditions are favorable for Legionella growth, such as cooling towers, whirlpool spas, hot tubs, humidifiers, hot water tanks, and evaporative condensers of large air-conditioning systems.

Health officials are testing water from all cooling tower systems in the area of the cluster in the Bronx.