The New Jersey Department of Health (NJDOH) is investigating a possible cluster of Legionnaires’ disease cases in residents of municipalities across Passaic County and Bergen County and is encouraging residents who develop symptoms suggestive of Legionnaires’ disease to seek medical evaluation.
Legionnaires’ disease is a severe form of pneumonia — lung inflammation usually caused by infection with the bacterium known as legionella — was first discovered in 1976 when members of the American Legion became sick when attending a convention in Philadelphia.
Most people catch Legionnaires’ disease by inhaling the bacteria from water or soil. Older adults, smokers, and people with weakened immune systems are particularly susceptible to Legionnaires’ disease.
The legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Pontiac fever usually clears on its own, but untreated Legionnaires’ disease can be fatal.
As of August 4, NJDOH has been notified of nine confirmed cases of Legionnaires’ disease among individuals residing in neighboring Passaic County municipalities, along with one additional case in a neighboring Bergen County municipality.
The onset of symptoms for these cases occurred between May 27 and August 1, 2023. Reports were submitted to NJDOH between June 6 and August 4, 2023.
NJDOH is actively collaborating with the local health departments in Passaic and Bergen Counties to investigate these cases and any potential sources of infection.
In late July, NJDOH alerted local health departments, health care providers, and other public health partners in the area regarding the elevated number of reported cases.
This is the same general region that experienced an increase in cases last winter. At that time, an investigation did not determine a common cause. The current investigation is still ongoing.
“Early diagnosis is key to effectively treating Legionnaires’ disease,” said New Jersey Acting Health Commissioner Dr. Kaitlan Baston. “Although the risk of contracting Legionnaires’ disease if you live in or have recently visited Passaic or Bergen counties remains low, individuals who develop pneumonia-like/respiratory symptoms should visit their health care provider immediately to be evaluated.”
Legionnaires’ disease is a type of pneumonia (lung infection) caused by bacteria called Legionella.
It is important to note that symptoms of Legionnaires’ disease are similar to those of COVID-19 and other respiratory illnesses such as flu. Symptoms can include fever, chills, cough, shortness of breath, chest pain, muscle aches, and headache.
If Legionnaires’ disease is suspected, only tests ordered by a doctor can confirm the diagnosis. Although Legionnaires’ disease is a serious illness, it is treatable with antibiotics.
Although prompt treatment with antibiotics usually cures Legionnaires’ disease, some people continue to have problems after treatment.
As it can take up to two weeks for symptoms to develop, NJDOH recommends that those who develop these symptoms within two weeks of visiting Passaic or Bergen counties seek medical attention.
It is rare for healthy people exposed to Legionella to develop Legionnaires’ disease. However, people over the age of 50, especially those who smoke, or those with certain medical conditions, including weakened immune systems, chronic lung disease or other chronic health conditions, are at increased risk for Legionnaires’ disease if exposed.
Legionnaires’ disease is not transmissible from person to person.
People can get Legionnaires’ disease by breathing in aerosolized (small droplets of) water containing Legionella bacteria, which can come from cooling towers used in air-conditioning systems, hot tubs, cooling water misters, decorative fountains, and plumbing systems.
Home air conditioning units—both central or in-window—do not use water to cool and are not a risk for Legionella growth.
In rare instances, individuals may also become sick when water containing Legionella is aspirated into the lungs while drinking (“goes down the wrong pipe”), particularly among those with swallowing difficulties.
NJDOH receives about 250-375 reports of Legionnaires’ disease each year and works closely with local health departments to investigate potential sources of infection. Investigations can be lengthy and identifying the exact source is often challenging.
Any potential sources found will be addressed and remediated to prevent further transmission.
For further information and Frequently Asked Questions on Legionnaires’ disease, visit the Department’s website.