New York City health officials are now investigating the Legionnaire's disease outbreak that started in the South Bronx, CBS Local News reported.

According to several reports, officials have recorded 31 cases since July 10. Two people positive for the infection have died, but it remains unclear if the disease is indeed the cause of death, as reported by Alice Grainer from CBS 2.

In a more recent update, health officials have reported that the number of cases in the area has increased to 46.

ABC 7 Online report stated that two rooftop cooling systems — one from Concourse Plaza Housing and the other from Lincoln Hospital — have tested positive for the bacteria.

The cases reported were from South Bronx neighborhoods, namely Morrisania, Mott Haven, High Bridge, and Hunts Point.

Health officials are now testing the waters from the aforementioned areas to find out the real source of the outbreak.

Legionnaire's disease is caused by Legionella pneumophila, a bacterium commonly found in water systems. The bacteria cause a severe form of pneumonia, which can be lethal most of the time, according to Legionella.org

The bacteria got its name back in 1976, where a pneumonia outbreak affected people who attended the American Legion held in Philadelphia.

Approximately 10,000 to 18,000 people in the U.S. go down with the infection each year.

The disease is not transmitted through contact with an infected person, but rather from breathing vapor or mist that contains the bacteria. Symptoms include the typical fever, chills, and cough.

The Centers for Disease Control and Prevention (CDC) said that most infected people tend to recover over time, but between five to 30 percent can die.

People who face a high risk of getting the disease are those in the middle-aged or older group, particularly those who have lung disease or weak immune systems, as well as those who smoke.

It is advised that those who observe the symptoms should immediately seek medical attention and request to be tested for the disease.