Public Health officials say three cases of legionnaires' disease have been confirmed at an apartment building in the Halifax area where four possible cases were suspected.

Medical Health Officer Gaynor Watson-Creed says the cases were found in residents of the Alderney Manor apartment building and measures will be taken to treat the water in the complex as a measure to prevent further cases.

Nancy McLean is one of about 200 residents in the building. She says having to follow strict safety precautions is both difficult and stressful.

"Last night I started having anxiety attacks because of all the stress of it,” she said. “Just the worry and the stress that they're putting us through."

Watson-Creed says tests are still being carried out to determine if the building is the source of the illness, but the treatment of the building's water will continue as a precaution.

"It lets us know that we're going in the right direction with our investigation, which is what we would hope for," she said.

QEII Director of Bacteriology Ross Davidson says legionella is difficult to get rid of.

"Using chloramination or super-heating the water - and that may reduce the numbers of bacteria but it certainly doesn't guarantee that you eliminate it," he said.

Davidson says most people are exposed to the bacteria on a regular basis, but those with underlying health conditions are at a higher risk for getting infected.

“For the very vast majority of people, we are absolutely at no risk,” he said.

Watson-Creed says health officials will continue to look at fresh cases of pneumonia in Dartmouth with suspicion as it's possible more people with the illness will be identified.

“What we're hearing about is all pneumonias, whether or not they look like legionella or not,” she said. “That's why those numbers are changing rapidly - because at this point people are doing exactly what we asked them to do, which is having a high index of suspicion."

People can contract the illness after breathing in small droplets of water or mists contaminated with bacteria and can suffer fever, chills, dry cough, muscle aches, headache and diarrhea.

The health officer said a consultant is being brought in by the building manner to run the water through a heating process that kills the clusters, if they are present in the water system.

With files from the Canadian Press and CTV Atlantic’s Suzette Belliveau.