The city is investigating a likely cluster of Legionnaires’ disease in the South Bronx that has sickened five people and killed one, health officials said Thursday.

The city health department said four other people were diagnosed with the disease in connection with the cluster in parts of the Melrose and Morrisania neighborhoods, including ZIP codes 10451 and 10456. Results are pending for other potential cases.

The South Bronx cluster is the second identified in New York City this summer, following an outbreak on Manhattan’s Upper East Side in July.

Eleven people died and 94 were diagnosed in connection with the Upper East Side outbreak, making it the deadliest cluster in the city since a 2015 outbreak in the Bronx killed 17 people. Legionnaires’ disease is a type of pneumonia caused by Legionella bacteria and can be contracted by inhaling water vapor that contains the bacteria.

The city has collected samples from cooling towers in the affected South Bronx neighborhoods and is testing them for Legionella bacteria. Officials said building owners will be ordered to clean and disinfect any towers that test positive.

The city health department said it will begin distributing information in multiple languages and holding town halls in the affected area Friday and throughout the weekend.

Health officials are urging people who have lived, worked or visited the affected area since late August to seek medical attention if they develop flu-like symptoms, including fever, cough or difficulty breathing. Legionnaires’ disease is not contagious and can be treated with antibiotics when caught early.

This is a developing story and may be updated.