"By devastating a nearly victorious Colonial American army besieging Quebec City in 1776, smallpox preserved Canada for the British Empire and left a string of mass graves along the army's line of retreat from Fort Chambly, near Montreal, to Crown Point, New York."
Smallpox: Ten Years Gone
DONALD R. HOPKINS, MD, MPH
https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.78.12.1589