Rideau Canal - Malaria In Canada
Some people were surprised to hear that malaria was such an issue during construction of the Rideau Canal. So this week we look at its origins in Canada and ask: if it was so widespread... where did it go?
EPISODE NOTES
TRANSCRIPT
In our intro to the Rideau canal, I said that malaria was the single biggest cause of death among workers. And that fact surprised some people! So today we’re gonna kick back, pour a G&T, and get some answers about this horrific disease: how did we get malaria in Canada? And - where did it go?
It’s worth a moment to understand how unavoidably awful malaria was during construction of the Rideau Canal. It was considered a miracle if you went a couple of years without catching it. Infection rates among workers could top 60% per year, and no surprise - they were working 14 hour days, six days a week in the summer. A labourer at the Jones Falls Dam said he’d go to his death with a smile - because he knew hell would be preferable to working on the Rideau Canal.
And once you inevitably caught malaria? Let John Mactaggart, the Rideau Canal’s clerk of works tell you what you had to look forward to:
“…an attack of bilious fever, dreadful vomiting, pains in the back and loins, general debility, loss of appetite…”
“…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…”
It had a few names - ague, swamp fever, the shakes - but its official name tells you how little they understood it: mal aria, in Italian - bad air. It was assumed you got it by breathing around stagnant water and rotting vegetation in swamps.
If anything the truth is weirder: all that pain and suffering from a microscopic creature carried around by another tiny creature. A parasite in the genus plasmodium, transported and injected by mosquitos. And there was no shortage of mosquitos on the Rideau.
But how did those mosquitos end up being carriers of malaria in the first place? How did it get to Canada?
There’s a clue here, at lock 32. Poonamalie lockstation. Interesting name. It happens to be an anglicization of Poovirundhavalli, a suburb of Chennai in India.
So why is a lockstation on the Rideau named after a suburb in India? In a word: topiary. The officer of the royal engineers who named it thought nearby cedar-lined roads reminded him of a former post - in India. And what do they have in India? Endemic malaria.
Our best guess is that British officers being rotated through the colonies picked up malaria, say in India, and brought it with them to Canada, where it found swarms of welcoming mosquitos and made the five years of Rideau canal construction utterly miserable.
Which just leaves the question: if it was everywhere - where did it go? For that, we have two big things to thank.
One, we terraformed. We chopped down trees and drained swamps for settlement and farming. This drastically reduced mosquito breeding grounds, and cases dropped.
Two, an effective treatment got cheaper and more available. For a long time we knew that chewing the bark of the Cinchona tree would help - they were known as ‘fever trees’. But in 1820, the active ingredient in the bark was extracted and isolated: quinine.
The British were quick to distribute it to their troops in high-risk areas, in a form that was easy for them to administer. They called it ‘tonic water’.
So next time you have a Gin & Tonic, maybe raise a glass to the thousand workers who gave their lives for this canal.