‘Then the shaking begins’: When malaria was a fact of life in Ontario

During the late 18th and much of the 19th century, Ontarians faced a different kind of variant — one carried by a buzzing, biting threat
By Jamie Bradburn - Published on Oct 27, 2021
Painting by C.W. Jeffreys of John By overseeing the building of the Rideau Canal. ( Library and Archives Canada, Acc. No. 1972-26-795)



In a letter sent to her mother in November 1834, Catherine Parr Traill apologized for a long silence. “When I tell you it has been occasioned by sickness,” she wrote, “you will cease to wonder that I did not write. My dear husband, my servant, the poor babe, and myself, were all at one time confined to our beds with ague.” She believed her family’s illness “had its origin in a malaria” due to stagnant water in a flooded cellar under the kitchen of their home near Peterborough. “The heat of the cooking and Franklin stoves in the kitchen and parlour, caused a fermentation to take place in the stagnant fluid before it could be emptied; the effluvia arising from this mass of putrefying water affected us all.”

Whether it was known as ague, swamp fever, or “the shakes,” malaria was a serious concern in Ontario during the late 18th century and much of the 19th century. The disease was present in North America as early as the 16th century; there are various theories as to how it reached Ontario — through British soldiers previously posted in such places as the Caribbean and India, perhaps, or through United Empire Loyalists who migrated following the American Revolution.

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Although the mechanism of malaria spread was not understood until the end of the 19th century, we now know that Ontario mosquitos carried a variant, Plasmodium vivax, that, while less severe than those found in tropical and sub-Saharan areas, was miserable enough. Given cramped living and working conditions, it was easy for mosquitoes to spread the disease by biting one person after another. Marshes, swamps, and places where dams had created stagnant ponds were ideal breeding grounds for mosquitoes, and the lower Great Lakes (especially modern-day Chatham-Kent and Essex and Lambton counties) and areas along the Grand River from Brantford southward and near the construction of the Rideau and Welland Canals became malarial hotspots. 

painting of a river and trees
A painting by Elizabeth Simcoe of the Don River, 1793. (Toronto Public Library/Baldwin Collection of Canadiana)

The common belief among public and medical officials was that malaria was due to poor air quality created by gases released by stagnant water or rotting vegetation in swampy areas — the name of the disease derived from an Italian term for “bad air.” In a report published in the Canada Lancet in 1873, a Stratford physician theorized that, because it spread among those in close contact with one another, malaria was possibly communicable. Peruvian cinchona bark, from which quinine was later extracted, was recognized as a treatment in the early 19th century but was initially too expensive for labourers to afford. Bleeding, plasters, and purging might be prescribed. A Toronto medical-school lecturer in the 1860s believed frightening a patient would shock the malaria out of them. 

The first lieutenant-governor of Upper Canada, John Graves Simcoe, knew malaria all too well. In both early capitals — Newark (today’s Niagara-on-the-Lake) and York (today’s Toronto) — families and government officials were laid low by ague. His wife, Elizabeth, wrote several entries in her diary in which she described falling ill; their infant daughter, Katharine, succumbed to the disease in 1794. Elizabeth also noted that there were so many mosquitoes she could hardly write; her hands were “always occupied in killing them or driving them away.”

Malaria seriously affected the development of the Baldoon Settlement near present-day Wallaceburg. When Lord Selkirk visited the site in early 1804 during a tour of Upper Canada, the Chenail Écarté and its surrounding waters near Lake St. Clair were unusually low. When the first settlers arrived in September of that year, they discovered that constant rainfall had left the land waterlogged and swarming with mosquitoes. Within a month, most had fallen ill, and by the end of November, 16 of 102 people had died. That marked the beginning of a string of disasters — including incompetent management, the land’s inability to support sheep farming, and an American invasion during the War of 1812 — that led to the settlement’s collapse within a decade (Selkirk shifted his focus to the Red River Colony in present-day Manitoba).

For the rest of the century, Kent County was prone to malarial outbreaks. A provincial health report observed that 1881 was a particularly bad year; because of drought, dirty wells were filled with barrel loads of untreated water from stagnant streams, which doctors believed carried the illness. Improved land drainage, especially in Raleigh Township, reduced future outbreaks.

In other parts of the southwest, malaria affected the defining of the Canada-United States border in the aftermath of the War of 1812. During the summer of 1819, American and British teams fell ill while mapping the marshy western end of Lake Erie and the Detroit River; British commissioner John Ogilvy was among the three who died. When work resumed the following year, mapping was carried out in the marshier parts of Lakes Erie and St. Clair earlier in the season.  

The construction of the Rideau Canal during the late 1820s and early 1830s was a miserable experience for labourersand officials, many of whom were debilitated for months by the effects of malaria; roughly 500 died. In 1828, project supervisor John By decided to reduce excavation work by raising the dam at Kingston Mills (near the present-day interchange of Highways 15 and 401) to flood several marshes and swamps upstream. Around 13 per cent of the Kingston Mills workforce died as a result of malaria and of dysentery caused by the drinking of swamp water.

John Mactaggart, the Rideau Canal’s clerk of works during its early construction, provided a detailed description of malaria in his book Three Years in Canada:

The Fever and Ague of Canada are different, I am told, from those of other countries; they generally come on with an attack of bilious fever, dreadful vomiting, pains in the back and loins, general debility, loss of appetite, so that one cannot even take tea, a thing that can be endured by the stomach in England when nothing else can be suffered. After being in this state for eight or ten days, the yellow jaundice is likely to ensue, and then fits of trembling — these come on some time in the afternoon mostly, with all. For two or three hours before they arrive, we feel so cold that nothing will warm us; the greatest heat that can be applied is perfectly unfelt; the skin gets dry, and then the shaking begins. Our very bones ache, teeth chatter, and the ribs are sore, continuing in great agony for about an hour and a half, and a profuse sweat ensues, which lasts for two hours longer. This over, we find the malady had run one of its rounds, and start out of bed in a feeble state, sometimes unable to stand, and entirely dependent on our friends (if we have any) to lift us on to some seat or other.

Mactaggart himself fell ill in 1828, shortly before he was dismissed from the project for allegedly being drunk on the job. Long-term complications may have hastened his death less than two years later. 

painting of a small settlement surrounded by trees
"Brewer's Lower Mill; View down the Cataraqui Creek, & and Clearing made for the Canal. Excavation for the Lock just commenced, 1829," by Thomas Burrowes, 1829. (Archives of Ontario, C 1-0-0-0-67)

To improve working conditions, By ordered the clearing of all trees within 250 feet of each side of the work sites and the draining of marshes and swamps to reduce the amount of bad air. Although this wasn’t its goal, his plan reduced the number of mosquitos, and cases went down. Throughout the rest of the canal’s construction, waves of malaria occurred between mid-August and late September each year. They were especially prevalent along the Cataraqui River and at “the Isthmus,” near present-day Newboro, where the caseload required the erection of a temporary hospital. The infection rate ranged from 10 to 50 per cent and did not discriminate by position — even By fell ill following an inspection tour in September 1829. Though it cost more, some work was done during the winter to reduce strain during the late summer. Rates fell after the canal was completed in 1832, and, in 1834, a doctor who travelled its length reported no cases. 

There are several theories as to why malaria faded away. The clearing of forests produced agricultural land, where livestock and other animals provided blood for mosquitos to feed on. Marshy areas near settlements were filled in or drained, reducing the swampy breeding grounds. Home-construction methods improved; newer homes generally had fewer cracks and crevices than log cabins and therefore offered fewer mosquito-friendly hideaways. Quinine treatments became more affordable. 

While it’s unlikely Ontario will again see a 19th-century style mass outbreak, some experts say that climate change may give malaria new life in the province. “As we get slightly warmer, the mosquito season is slightly longer,” University of Toronto pharmacy professor Ian Crandall told TVO.org in 2016. “A little warming leads to a whole lot more malaria.”

Sources: Labourers on the Rideau Canal 1826-1832: From Work Site to World Heritage Site, Katherine M.J. McKenna, editor (Ottawa: Borealis Press, 2008); Military Paternalism, Labour, and the Rideau Canal Project by Robert W. Passfield (Bloomington, Indiana: AuthorHouse, 2013); Second Annual Report of the Provincial Board of Health of Ontario 1883 (Toronto: C. Blackett Robinson, 1884); The Backwoods of Canada by Catherine Parr Traill (London: Charles Knight, 1836); The Capital Years: Niagara-on-the-Lake 1792-1796, Richard Merritt, Nancy Butler, and Michael Power, editors (Toronto: Dundurn, 1991); The Silver Chief by Lucille H. Campey (Toronto: Natural Heritage, 2003); Three Years in Canada: An Account of the Actual State of the Country in 1826-7-8 by John Mactaggart (London: Henry Colborn, 1829); Toronto Past and Present by Charles Pelham Mulvany (Toronto: W.E. Caiger, 1884); the September 1873 edition of the Canada Lancet; the Fall 1984 edition of the Canadian Bulletin of Medical History; and the Fall 2004 edition of Michigan Historical Review.

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