Tropical Disease in Untropical Places: Thinking of Malaria in Canada

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This is the ninth post in the Wetland Wednesday series, edited by Gabrielle McLaren.

Thank you to Heather Poussard for her editorial support.

Military physician James Douglas was alarmed to report that in a six-week period in 1814, half of the British troops at Fort Chippawa were hospitalised with malaria. The situation became so dire that Fort Chippawa was evacuated to “a more salubrious situation” during the War of 1812. “There is perhaps no situation in which a medical practitioner can be placed,” Douglas reflected, “more painful to his feelings than . . . witnessing the effects of an obstinate intermittent fever spreading its ravages amongst the wounded.” 

Douglas shared these and other malarial encounters in his 1819 Medical Topography of Upper Canada, which mobilised knowledge of disease to enable successful colonial activities—a key concern of 19th century tropical medicine, as scholars of the British Empire have shown.1 With Douglas’s work as a starting point, I want to provide a basic sketch of malaria in Upper Canada, and its implications on settler identity formation.

Cover of John Douglas’s Medical Topography of Upper Canada.

“In Unhealthy Situations” : Malaria in Upper Canada 

While more research is badly needed, malaria was seemingly brought to Canada by settlers–possibly troops moved across the British Empire, possibly Loyalists fleeing the American South, where malaria is well-documented on plantations. Historical research on malaria is complicated by the fact that until the late 19th century, malaria was attributed to disease-causing gases called miasmas.2

Because miasmas were understood to be place-based, Douglas’s medical text describes Upper Canada’s vegetation, soil composition, precipitation, and harsh seasons in order to comment on the health of specific places. He considered York (Toronto) “liable to be attacked by intermittent fever,” Kingston better but “by no means exempted from sickness,” Fort Erie “unhealthy and thinly inhabited,” and the West of Lake Ontario “but partially settled, and withal very unhealthy.”

Fort Chippawa was in such a marshy and “unhealthy situation” that “though a military position both in times of war and peace, it ought never to be garrisoned by troops except in cases of the most urgent necessity.” Douglas wrote that: “The tract of land which stretches from Chippawa to Fort Erie, is in many parts deep and marshy, and divided by narrow creeks, the swelling and recession of whose waters are also dependent on the increased or diminishing size of the river Niagara. It is, therefore, not to be wondered at, that settlers in this line of territory are at times indisposed by sickness.” Douglas’s concern about “marshyness” here reflects the longstanding association of wetlands and swamps with disease–one that likely developed because wetlands are prime breeding grounds for the Anopheles mosquitoes that carry malaria. Locating the source of disease in specific ecosystems led settlers to manage disease by targeting their environments directly. 

Village of Chippawa, watercolour by military surgeon Edward Walsh, 1804. Accessed via the Brown Homestead.

“The Labours of Industry”: Getting Rid of Malaria 

For Douglas, the only way out of Upper Canada’s malaria problem was through. Like many of his contemporaries who subscribed to theories of improvement, Douglas considered that “the rude physiognomy of nature” could be “soften[ed]… by degrees to the labours of industry.” He happily anticipated “the future grandeur of this majestic country, when an increase in population shall cover its surface, and when those bounties which nature at present scatters so profusely around shall not pass unseen nor unenjoyed.”

The processes designed to “soften” Upper Canada’s disease landscape—such as agriculture and settlement—were also tools of settler colonialism. For example, Lakota journalist and historian Nick Estes describes agriculture as “a mode of production [that] personifies settler colonialism: it’s sedentary and mostly permanent; it reproduces itself; and it always eats more land and water. As it expands, it eats away at Indigenous territory, destroying fauna and flora and annihilating Indigenous subsistence economies.”3 Therapeutic interventions on the landscape materially entrenched settler colonialism. 

Wetlands faced the double challenge of being eliminated to create agricultural land settlers could recognize as “productive,” and to eliminate disease at the source. Surveyor John Mactaggart, for example, raged against the “infernal” Cranberry Marsh in his travel journal, recounting how “the mist of the marsh is extremely noxious to life” and rejoicing that it had been flooded and turned into a lake. Kingston-based physician Edward Barker noted that malaria infections “have not been so prevalent” since the region’s hydrology was seemingly brought under human control by the Rideau Canal. 

For a slew of reasons we need more research to understand, malaria disappeared from Canada’s disease landscape by the mid- to late-19th century. Wetlands disappeared during the same period. Between 1800 and 2002, Niagara County, where Fort Chippawa had stood, lost 85.1% of its wetland coverage—with Southern Ontario losing 72.3% of its overall wetland coverage. This has and had disastrous effects for biodiversity, water quality, flood abatement, and climate change, as an estimated 1.9 billion metric tons of carbon was released from Southern Ontario’s wetland over the last 200 years.

Map of Upper Canada, from “Ten Years of Upper Canada in PEace and War, 1805-1815.” Accessed via Picryl.

“Though Living in Places Which Are Productive of Disease” : Malaria and Settler Identity Formation 

Douglas believed that settlers could become immune to malaria if they successfully acclimatised (or their bodies’ ‘got used’) to Upper Canada’s climate and diseases. He wrote that: 

As [settlers] grow up to manhood, their constitutions become naturalized to the climate… they seldom relapse into fever . . . Many of the old settlers, though living in places which are productive of disease, and who, after their arrival in the country, had been annually seized with obstinate agues, may now be seen, even at an advanced period of life, actively employed with their numerous offspring in the cultivation of their farms. 

The image Douglas uses to epitomise successful acclimatisation is male, able-bodied, productive, and as much about settlement as it is about health. The aspirational “numerous offspring” working the family farm underscores the then-urgent need to populate Upper Canada to prevent further American aggression and fully exploit the colony’s natural resources. His observations of “old settlers” thriving “in places which are productive of disease” make an important suggestion: that to survive malaria, to embody a place through the disease it created, was to become of a place. In other words, to survive malaria was to become Upper Canadian. 

Clearly, malaria shaped how settlers came to understand Upper Canada’s environment, interact with it, and forge their identity as settlers. So why is there so little research about malaria’s history in Canada? I wrestled with this historiographical question while writing my MA thesis on disease during the Rideau Canal’s construction.

While there’s likely no one reason for this historiographical gap, I want to suggest that it may be an issue of scale. Malaria is no longer endemic to Canada, partially because the wetlands and other environments where humans, mosquitos, and parasites interacted were so intensely changed. Unlike infectious diseases like smallpox and cholera, malaria was firmly place-based, meaning that local and environmental histories are best suited to telling its history–if we can reconstruct past environments. 

Or maybe this all comes down to settler colonialism’s tendency to, as Lorenzo Veracini put it, “obscur[e] the conditions of its own production.”4 To think of malaria in Canada is to think of a small, resource-poor colony on the outskirts of the British Empire, and of the ecosystems and lifeways it destroyed to create itself. It is much easier to follow colonial medicine’s lead and think of malaria as a “tropical disease,” and the problem of other, poorer, and non-white countries where malaria remains endemic (a critique Randall Packard makes well of malaria in the 20th and 21st centuries).5 Besides, Canadian identity is largely steeped in the climate’s decisively un-tropical nature: not its once mosquito-ridden wetlands. 

Mouth of the Chippawa River Near the Site of Fort Chippawa, photo by John Stanton 11 Aug 2013. Accessed via Wikicommons.


  1.  See, for example: Conevery Bolton Valenčius. The Health of the Country: How American Settlers Understood Themselves and Their Land. New York: Basic Books, 2002; Philip Curtin. Death by Migration: Europe’s Encounter with the Tropical World in the Nineteenth Century. New York City: Cambridge University Press, 1989; Rohan Deb Roy. Malarial Subjects: Empire, Medicine and Nonhumans in British India, 1820-1909. Cambridge, New York: Cambridge University Press, 2017; Douglas M. Haynes, Imperial Medicine: Patrick Manson and the Conquest of Tropical Disease. Philadelphia: University of Pennsylvania Press, 2001; Jessica Howell. Exploring Victorian Travel Literature: Disease, Race, and Climate. Edinburgh: Edinburgh University Press, 2014; Randall Packard, The Making of a Tropical Disease: A Short History of Malaria (Baltimore: John Hopkins University Press, 2007). 
  2. The two main articles on malaria in 19th century Upper Canada are: Charles G Roland, “‘Sunk under the Taxation of Nature’: Malaria in Upper Canada” in Health, Disease, and Medicine: Essays in Canadian History, ed. Charles G. Roland, 154-169. Clarke Irwin Inc, 1983; Albert Murray Fallis, “Malaria in the 18 and 19 centuries in Ontario.” Canadian Journal of Health History/Revue canadienne d’histoire de la santé 1, 2 (1984): 25-38. ↩︎
  3. Nick Estes. Our History Is the Future: Standing Rock Versus the Dakota Access Pipeline, and the Long Tradition of Indigenous Resistance. (Verso Books, 2019). Kindle Location 2299 ↩︎
  4. Lorenzo Veracini. Settler Colonialism: A Theoretical Overview. (London: Palgrave MacMillan, 2010). ↩︎
  5. Randall Packard, The Making of a Tropical Disease: A Short History of Malaria (Baltimore: John Hopkins University Press, 2007). ↩︎
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Gabrielle Mclaren

Gabrielle (she/elle) holds an MA in History from Concordia University, where her thesis dealt on malaria's impact in Upper Canada, using the construction of the Rideau Canal as a case study. She graduated from Simon Fraser University in 2020 and will be starting a PhD at York University in Fall 2024. She is currently based in Tio'Tia:ke, Montréal where she works as the Associate Director for the SSHRC-funded Deindustrialization and the Politics of Our Times series.

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