Malaria is an old Canadian disease.
It was an important cause of illness and death in the past century in Upper and Lower Canada and out into the Prairies. 3 Malaria also appears to have had an important effect on the health of the Northwest Mounted Police in the Prairies. Canada's own William Osler popularized the use of the microscope for the diagnosis of malaria in North America in the late 19th century. The endemic malaria in North America was probably reinforced each spring by waves of infected immigrants from Europe. Several of our indigenous Anopheles mosquitoes were, and still are, capable vectors of human plasmodia.