The New York City Health Department is investigating an outbreak of Legionnaires' disease in the South Bronx.

City officials said 31 cases of the Legionnaires' disease have been reported since July 10 in Highbridge, Morrisania, Hunts Point and Mott Haven sections of the Bronx. Two patients with the deadly disease have died, CBS news reported.

"We are concerned about this unusual increase in Legionnaires' disease cases in the South Bronx," Health Commissioner Dr. Mary Bassett said in a statement. "We are conducting a swift investigation to determine the source of the outbreak and prevent future cases. I urge anyone with symptoms to seek medical attention right away."

The Health Department is investigating the two deaths and their relationship to the outbreak. The department is also testing water from cooling towers, plumbing systems and other potential sources in the area to determine the source of the outbreak, DNAinfo reported.

"We know a lot about Legionnaires Disease, and we know a lot about outbreaks- we've investigated them over the years. This particular outbreak is still under investigation, so we have an evolving situation...in which the numbers may change," Bassett said at a press conference Wednesday, according to DNAinfo.

Legionnaires' disease is a severe form of pneumonia that is caused by the bacteria Legionella. New Yorkers with respiratory symptoms, such as fever, cough, chills and muscle aches, are advised to promptly seek medical attention. Symptoms of the disease also include headache, fatigue, loss of appetite, confusion and diarrhea.

Symptoms usually appear two to 10 days after significant exposure to Legionella bacteria. Most cases of Legionnaires' disease can be traced to plumbing systems where conditions are favorable for Legionella growth, such as whirlpool spas, hot tubs, humidifiers, hot water tanks, cooling towers, and evaporative condensers of large air-conditioning systems.

"This is a common and readily treated pneumonia and we want to be sure that people get care and that the healthcare providers are thinking about this diagnosis," said Bassett.

The disease cannot be spread from person to person. Groups at high risk for Legionnaire's disease include people who are middle-aged or older, people with chronic lung disease or weakened immune systems.

Earlier this year, preliminary tests done by the Health Department found that the cooling towers at Co-op City in the Bronx were contaminated with Legionella.