It seems New Yorkers are beginning to worry in response to the seven people who have died from the Legionnaires’ disease outbreak this week in the Bronx. Even though all of the victims were older adults with other underlying medical conditions, young people can become infected as well if the disease lives in a concentrated area, usually a building. A total of 81 cases were reported and 64 of those infected have been hospitalized.

Let’s start with what exactly Legionnaires’ disease is. Contracted by inhaling the bacteria, this disease is a severe form of pneumonia or inflammation in the lungs manifested through an infection. The culprit? A bacterium known as legionella, hence the name, Legionnaires’.

Who’s most at risk? Those with weakened immune systems and chronic lung disease are very susceptible to inhaling the bacteria. Older adults as well as heavy smokers are also at risk.

If you’re nervous, now’s the time to exhale. You can’t catch this from someone sitting next to you, rather from inhaling the bacteria. Often the bacteria stems from a water source such as air conditioning, cooling towers or even showers. How does this bacterium grow? The answer is outside. Legionella bacteria can survive in soil and water, but in this state rarely causes infection. However, if the bacteria travels inside, it can multiply in many types of water systems, usually in everyday water sources we use such as air conditioners and swimming pools. Because most of the past outbreaks occur in large buildings, perhaps complex water systems that support these areas allow the bacteria to grow at a rapid pace, thus spreading more easily.

Wondering what the signs of this disease are? Well they can often be mistaken for other common conditions such as the flu. Think fever, chills, cough, headache and muscle pain. The reason? Well, the legionella bacterium is also responsible for a condition known as Pontiac fever, a milder illness that resembles the flu. Both diseases can occur separately or together. Pontiac fever usually clears on its own, whereas Legionnaires’ can be fatal if gone untreated.

Generally symptoms don’t surface until 2-10 days after the bacteria is contracted.

So what does this lead to? Respiratory failure (inability to breathe correctly), septic shock (severe and sudden drop in blood pressure) and acute kidney failure can stem from contracting Legionnaires’ disease.

According to the Centers for Disease Control and Prevention, most patients recover, but a small percentage (between 5%—30%) die from the disease.

While prompt treatment using antibiotics can cure the infection, some patients continue to experience symptoms after treatment. Although, most known for primarily affecting the lungs, Legionnaires’ can manifest infections in open wounds and other parts of the body, including the heart, in some severe cases.

The commissioner of the health department, Dr. Mary Bassett, expressed that a swift investigation was underway to detect the source of this outbreak and prevent future cases. The department is currently testing water from various potential sources that may have started the outbreak.

Throughout the areas infected in the Bronx, five locations have confirmed positive traces of the legionella bacteria, including a hospital and hotel. The city is requiring these buildings conduct full environmental cleaning and other corrective measures.

The mayor has said that most New Yorkers are not at risk. However, the elderly and homeless population are most at risk. If the bacteria doesn’t remain under control, we could see a further spread of the infection. Disease detectives are on the hunt for the source of the bacteria. Stay tuned and in the meantime, if you or your loved ones unexpectedly experience any of these symptoms, be sure to use extra caution and get checked as soon as possible.