The mysterious illness that caused the deaths of 16 elderly people at a Toronto nursing home has been identified as Legionnaire's disease by health officials.

He adds, however, that, "Some people are fragile enough that they may still succumb to this."

Health experts, including the World Health Organization, claim the illness is disseminating and remains contained to the Seven Oaks Home for the Aged in the eastern suburbs of Toronto.

Legionnaires' disease is a type of pneumonia named after a severe outbreak that affected a meeting of the American Legion in Philadelphia in 1976.

In the United States, an estimated 8,000-18,000 cases occur each year, but only a fraction are reported.