4th death reported in Legionnaires' disease outbreak on NYC's Upper East Side

The New York City health commissioner revealed more somber news on Monday, announcing the fourth death related to the Upper East Side Legionnaires' disease cluster.

However, Dr. Alister Martin also said there is renewed optimism that the outbreak may be close to running its course.

"A fourth person has sadly died from Legionnaires' disease on the Upper East Side. We mourn their passing, and our thoughts are with their family and loved ones," Martin wrote on social media, later adding, "At this time, we believe any source of exposure has likely been eliminated. We have not seen anyone with new symptoms in over a week. We are focused on inspecting every cooling tower that tested positive and enforcing our laws to their fullest extent."

76 cases so far

Monday's announcement marked the four consecutive day of a death related to the cluster.

As of Monday, a total of 76 Legionnaires' disease cases have been connected to the cluster, health officials say. Of those patients, four have died, seven are currently hospitalized, 53 have been discharged from the hospital, and 12 did not need to be hospitalized.

Health officials believe the source of the outbreak -- suspected to be water vapor containing live Legionella bacteria from a cooling tower in the area of the 10028, 10075 and 10128 ZIP codes -- has been eliminated after they ordered 76 buildings that tested positive for the bacteria to undergo precautionary cleaning.

Anyone who develops flu-like symptoms after spending time in the impacted area is encouraged to seek medical care.

For more information on Legionnaires' disease, including symptoms and prevention, visit the health department's website.