A third person has died in New York City amid an ongoing cluster of Legionnaires’ disease cases in the Upper East Side, according to health officials.

At least 74 cases have been identified and eight remain hospitalized, the New York City Health Department announced.

“It is with great sadness that I report a third person has died in connection with the Legionnaires’ disease community cluster on the Upper East Side,” New York City Health Commissioner Dr. Alister F. Martin said in a statement on Sunday. “Our hearts are with their family and friends as they mourn their loss.”

Health officials advised that anyone who has spent time in the affected zip codes 10028, 10075, 10128, including Carnegie Hill and Yorkville, should seek medical attention if they develop flu-like symptoms.

Legionnaires’ disease symptoms can appear up to 14 days after exposure, the NYC Dept. of Health said.

The department said it believes the source of the bacteria has likely been eliminated and that it will continue inspecting every cooling tower that tested positive for the bacteria.

Legionnaires’ disease is a severe form of pneumonia caused by inhaling the Legionella bacteria in small droplets of water mixed in the air or contaminated water accidentally going into the lungs.

The bacteria are found naturally in freshwater, but amounts generally don’t lead to disease. The bacteria typically grow best in warm water and in warm to hot temperatures, according to the Centers for Disease Control and Prevention (CDC).

The disease does not generally spread from person to person, but infections can occur if the bacteria get into a building’s water supply, including in shower heads, sink faucets, hot water tanks, heaters, cooling towers and other plumbing systems.

Legionnaires’ disease has increased in prevalence over the last decade, reaching a peak of 2.71 cases per 100,000 in 2018, the CDC said. Cases dropped during the first year of the COVID-19 pandemic and then rebounded in 2021.

Although most people recover from Legionnaires’ disease with antibiotics, certain patients — including those who are immunocompromised or who suffer from chronic lung diseases — can develop complications that can be fatal.

ABC News’ Mary Kekatos and Youri Benadjaoud contributed to this report.