The New York City Department of Health has launched an investigation into cases of Legionnaire's disease in the Bronx.

A total of four people have been diagnosed with the disease in Highbridge this month.

To date, there have been no deaths reported in association with the cluster and the Health Department says they are also testing cooling tower systems in the area as part of their investigation.

"It suggests that there is something environmentally wrong that we have to correct," says infectious diseases expert Dr. Michael Augenbraun of NYC Health + Hospitals/Kings County.

Legionnaire's disease is a type of pneumonia that is caused by the bacteria Legionella, which grows in warm water.

Most of the cases can be traced back to plumbing systems where conditions are favorable for the bacteria's growth -- even found in places like hot tubs and air conditioning systems.

Those diagnosed can get the disease by breathing in water vapor containing the Legionella bacteria and it is not transmissible from person to person.

However, there is still a concern for a specific group of New Yorkers at risk of being infected.

"The organism lives in water and is commonly found in water systems all over the place. It's found in lakes, rivers, it's found in the plumbing in your home," Augenbraun says. "The people that we're most concerned about who has the highest risk seem to be people whose immune systems are compromised in one way or another."

Legionnaires disease can be disguised as flu like symptoms like a cough, fever or difficulty breathing. Medical experts advise anyone who is experiencing these symptoms to contact a physician.