While some labourers lost their lives to construction – often as a result of mishandling dynamite – disease was by far the biggest killer during the building of the Rideau Canal. In the early days of construction, malaria caused the highest death toll, claiming the lives of hundreds of men, women, and children. Malaria was known by many names: fever, ague, lake fever, and swamp fever. The debilitating disease had been present in Ontario for over 200 years, but found an ideal home in the canal’s swampy construction area – a perfect breeding ground for mosquitoes, which were largely responsible for malarial infection and transmission. Smallpox, charbon (anthrax), dysentery, and cholera also swept through Bytown and along the canal line. There were limited options for treatment available; worse still, access to treatment was often dictated by social class. In the end, disease claimed as many as 500 lives while the canal was being built. Some of these victims can be found in cemeteries throughout Ontario; many, however, remain in unmarked graves to this day.