NEW YORK (CBSNewYork) — The death toll in the Legionnaires’ disease outbreak in the South Bronx has risen to four people.

New York City officials said Saturday all four who died were older adults and had additional, underlying medical problems.

The number of cases since the outbreak began on July 10 has also risen with a total of 65 confirmed cases — up from 57 on Friday, CBS2 Dave Carlin reported.

Most of the cases have been reported in Highbridge, Morrisania, Hunts Point and Mott Haven.

“Scary,” said Bronx resident Marlana Matthews. “I have a little one to have to worry about and take precautions I didn’t know was so close to home though.”

Deputy Health Commissioner Dr. Jay Varma tells WCBS 880’s Jim Smith they are doing the detective work to find the source and they’ve located at five infected building cooler towers.

City health officials said of the 22 buildings tested in the outbreak area, five buildings tested positive for the bacteria Legionella: Lincoln Medical and Mental Health Center, the Concourse Plaza Mall, the Opera House Hotel, a Verizon office building, and the Streamline Plastic Co.

“And those towers can generate a water mist and if that water has the bacteria in it, people walking around outside that building are at risk of getting the illness,” Dr. Varma said.

Remediation to remove the bacteria has been completed at all of the locations except at Streamline Plastic Co., where it is expected to be finished Saturday afternoon.

“We’ve cleaned all of those sources of infection,” Dr. Varma said.

City Health Commissioner Dr. Mary Bassett said earlier this week the outbreak has nothing to do with the city’s water towers or drinking water.

“There is no worry about our water supply. We are concerned about cooling towers, which release warm mist. The water supply in the South Bronx remains entirely safe,” she said.

Legionnaires’ disease can usually be traced to places favorable to Legionella growth such as cooling towers, hot water tanks, whirlpool spas, hot tubs, humidifiers and condensers in large air conditioning systems. It is spread through contaminated mist and is not contagious.

As health officials continue to investigate the outbreak, they urge anyone experiencing symptoms to visit a doctor.

Symptoms of Legionnaires’ disease include headache, fatigue, loss of appetite, confusion and diarrhea. Symptoms appear two to 10 days after exposure to Legionella bacteria.

The condition is easily treatable with antibiotics, Bassett added.

The Mayor’s office, Department of Health and Mental Hygiene, and local leaders are holding a town hall meeting Monday night at the Museum of the Arts to discuss the spread of Legionnaires’ disease in the Bronx.