The deadly outbreak of legionnaire’s disease in Quebec City has claimed 10 lives since late July, heath officials have confirmed.

As many as 165 people have so far been diagnosed with deadly legionnaire’s disease, which poses the greatest risk to people with frail immune systems.

The health officials noted that the most recent count included cases that were reported over the past 10-15 days, as the disease has an incubation period of 2-10 days.

The cause of the outbreak has yet to be determined. DRSP officials have said that they have already launched a probe to determine the cause.

Some experts are of the view that inappropriate maintenance of cooling units in air conditioning systems could be the root cause of the outbreak. Legionella bacteria breed in stagnant water in appliances like coolers, and then spread with droplets ousted by the appliances during operation.

The symptoms of Legionnaire's disease, which was discovered in 1976 during a convention in the U. S. where 29 people had died, include dry cough, pneumonia and high fever.