They had painful rashes, a high fever, muscle and joint pain and headaches — Zika virus’s toll on Canadian tourists was “more severe” than what was expected, according to a new study shedding light on the mosquito-borne virus’s reach on travellers.
New national research suggests that Zika hit Canadian travellers harder than its counterparts like dengue and chikungunya. The findings come out of data collected by infectious disease experts over the course of a year from the Canadian Travel Medicine Network — or CanTravNet, a network of travel clinics across the country.
“The common perception that Zika is a very mild illness wasn’t found in our results — for those who developed symptoms, the clinical outcomes were quite severe,” Dr. Andrea Boggild, clinical director of the tropical disease unit at the University Health Network, University of Toronto and Public Health Ontario, told Global News.
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As of Feb. 9, there were 473 travel-related and three sexually transmitted cases of Zika virus in Canadians, according to the Public Health Agency of Canada.
For Boggild’s study, she looked at the records of 1,118 travellers who visited travel clinics in B.C., Alberta, Manitoba, Ontario and Quebec for illnesses they picked up in Central and South America and the Caribbean between October 2015 and September 2016. Sick patients had to be referred to these travel clinics by their family doctor, emergency department physician or from a walk-in clinic.
Turns out, 41 people — nearly four per cent — had Zika virus, another 41 had dengue, and 23 — 2.1 per cent — had chikungunya.
Almost 60 per cent of travellers who contracted Zika were women, and 79 per cent of them were of child-bearing age. Three pregnant women were infected and two ended up with congenital infections that affected their babies.
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Two Canadians had symptoms of Guillain-Barre, a rare and potentially life-threatening attack on the nervous system which can cause paralysis.
That means 10 per cent of all Zika cases coming out of the travel clinics had severe complications.
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When it came to dengue or chikungunya, there weren’t any severe symptoms reported at all.
Eighty-eight per cent of Canadians who showed up to the travel clinics with Zika were battling rashes, 80 per cent had a fever, and half complained of muscle and joint pains and headaches.
About one in six travellers with Zika virus developed pink eye.
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The sample group made up only 12 per cent of Canadians who contracted Zika virus, though.
Boggild notes that these Canadians probably had the most severe symptoms. “It’s biased to more severe illness, but we didn’t see the same issues overrepresented in chikungunya or dengue,” she told Global News.
“The major takeaway point is that nothing from our study alters our current advice to pregnant women to defer travel to Zika-affected areas. If you’re worried, Canadians should be reminded to seek pre-travel medical consultations,” she said.
Like dengue, West Nile and yellow fever, Zika virus is a mosquito-borne tropical disease, meaning mosquitoes transmit the disease to humans.
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The Public Health Agency of Canada issued its own public health notice and travel health notice. It upped its travel recommendations, too.
“It is recommended that pregnant women and those considering becoming pregnant discuss their travel plans with their health-care provider to assess their risk and consider postponing travel to areas where the Zika virus is circulating in the Americas,” the PHAC advisory says.
carmen.chai@globalnews.ca
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