More people in New York City are sick with Legionnaires’ disease in what appears to be a new cluster of cases, health officials say.

So far, seven people who live or work in the Morris Park neighborhood of the Bronx have been hospitalized recently with Legionnaires’ disease, according to the New York City Department of Health and Mental Hygiene. Officials were notified of these cases last week.

The new cases are not related to the outbreak of Legionnaires’ disease that occurred in New York City over the summer, which was the largest in the city’s history, and sickened 120 people in the South Bronx. Officials traced that outbreak to a cooling tower at the Opera House Hotel, which was contaminated with Legionella, the bacteria that cause the disease.

An investigation into the new cluster is underway, and scientists have taken samples from all of the cooling towers in Morris Park to test for the bacteria, according to the health department. Officials have also notified health care providers in the area to look out for patients with symptoms of the disease, and conduct the necessary tests on these patients. [6 Superbugs to Watch Out For]

Officials urged New Yorkers with symptoms of Legionnaires’ disease, such as fever, cough, chills and difficulty breathing, to seek prompt medical attention. The disease most commonly affects older adults and people with weakened immune systems.

Legionella live in watery environments, such as cooling towers and air-conditioning systems, and symptoms can show from two to 10 days after a person is exposed to the bacteria. People get infected when they inhale airborne water droplets containing the bacteria, but the disease does not spread from person to person.

The outbreak this summer led to the passage of legislation requiring that building owners regularly test their cooling towers for the bacteria.

An estimated 8,000 to 18,000 people are hospitalized with Legionnaires’ disease each year in the U.S., according to the Centers for Disease Control and Prevention.

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