The city’s Department of Health is in the process of investigating two cases of Legionnaires’ disease found at a West Harlem apartment complex, officials said on Friday.

This is the first announcement of any form of investigation since an outbreak in the South Bronx last summer, which killed 12 and infected more than 120.

The two most recent cases of the waterborne illness emerged within the past 10 months at Savoy Park, at 2300 Fifth Ave.

The city sees an estimated 200 to 400 reports of the disease annually, officials said. The CDC estimates there have been at least 110 reported cases in the city so far in 2016.

Health Department officials report that the two cases cannot be considered part of an outbreak, and that a source has yet to be found.

“While the risk of infection to tenants is very low, as part of routine protocol to assess potential sources of Legionella, the department is working with the building management to test the building’s water supply,” health department spokesman Christopher Miller said.

The south Bronx outbreak last summer was traced to 15 cooling towers, which then prompted new city legislation. The building in West Harlem is not equipped with cooling towers.

“Residents of this building have been notified of the investigation and given relevant information about the disease and next steps,” Miller said.

While reports of Legionnaires’ disease have become relatively routine, the initial discovery of the disease was not.

In July 1976, just weeks after Philadelphia hosted the United States’ bicentennial celebration, hundreds flocked to its iconic Bellevue Stratford hotel for the city’s annual statewide convention.

However, within days of the conference, more than 100 attendees came down with mysterious cases of pneumonia. The public feared a deadly flu pandemic, but it wasn’t until five months later that CDC microbiologist Joseph McDade identified the legionella bacteria.

While he didn’t need an X-ray shooting 30 frames per second to solve the medical mystery, it took long months of research before he found anything of note.

Mcdade said in regards to Legionnaires’, the disease itself wasn’t new. But before the fatal outbreak, sporadic cases often went unnoticed.

“However when you get a very large outbreak of something, with 150 to 200 cases of disease, it cannot be ignored. It cannot be ignored,” said McDade. “Sometimes what it takes is a large outbreak of a disease to help you discover something that’s been percolating for a long time, undetected.”

Following the discovery of the legionella bacteria, he and others were then able to trace it back to previous, unsolved outbreaks.

“I still to this day continue to learn lessons,” said McDade. “Data becomes information, information becomes knowledge and hopefully someday knowledge collectively becomes wisdom.”

Fortunately, McDade’s discovery has made treatment and accurate information available for those who contract the disease in contemporary society.

For those in Harlem, officials reported that residents can still use and drink water, but those with compromised immune systems should take extra precautions.

In addition, officials advise that those with compromised immune systems take baths instead of showers, and refrain from being in the bathroom while the bath is filling.