The New Jersey Department of Health has opened an investigation into a possible cluster of Legionnaires’ disease cases near Passaic and Bergen counties.

The department said in a release that as of Dec. 28, they are aware of seven confirmed cases in individuals from Passaic and Bergen counties. Those cases were reported to the state Health Department between Nov. 9 and Dec 21. It also stated that it alerted health care providers of the increased number of reported cases.

The state Department of Health receives about 250-350 reports of Legionnaires' each year. It is now working with local health departments to identify the source or sources of the new confirmed cases.

"It’s a bacteria that can cause a type of pneumonia that in some patients can be severe," says Dr. Gian Varbaro, the chief medical officer at Bergen New Bridge Medical Center. “Legionella lives in water and soil - so it's usually around stagnant water or soil and that's where you see outbreaks."

People can get it by breathing in small droplets of water containing the Legionella bacteria. That can come from cooling towers, air conditioning units in large buildings, fountains and plumbing systems as well as hot tubs.

“Usually, they do what we call contact tracing, which a lot of people heard about last couple years through COVID,” says Varbaro. “There's usually a lot of epidemiolocal methods where they try to trace where the outbreak started and who else was exposed."

It could take up to two weeks from exposure for symptoms to develop. The symptoms include fever, chills, cough, shortness of breath, chest pain, muscle aches and headache.

Older people and those with underlying conditions are more at risk

Legionnaires’ disease is treatable in most through antibiotics.

Residents are advised to call their doctor if they develop pneumonia-like symptoms.