HALIFAX -- Public Health officials were investigating four possible cases of legionnaires' disease Thursday after confirming a positive case at an apartment building in the Halifax area.

Health authority spokesman Everton McLean said three of the possible cases were found in residents of the same building and were being treated in hospital.

McLean said he didn't know if the fourth possible case was also a resident of the building in the suburb of Dartmouth.

Officials said they were trying to identify the source of the bacteria and have not confirmed that it was contracted at the complex.

Health Minister Leo Glavine said lab results were expected Friday.

Glavine said public health officials were meeting with all other residents of the building to explain the situation.

"Knowing about legionnaires' disease and the history across the country and the United States, I was very concerned as soon as I heard that word and that we have a confirmed case," said Glavine.

"As we know, it is treatable with antibotics, but in elderly populations is where the great concern arises."

Medical Health Officer Gaynor Watson-Creed said most people have little risk of catching the disease, which is not contagious and can't be spread from person to person.

She said it appears the source of the cluster is localized and unlikely to pose a broader public risk.

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