US & Canada

Zika virus in Canadian patients 'more severe' than expected

An Aedes aegypti mosquito is seen through a microscope at en exhibition on Dengue fever on January 28, 2016 in Recife, Pernambuco state, Brazil. Image copyright Getty Images
Image caption Zika is commonly transmitted by mosquitoes

The impact of the Zika virus on infected Canadian travellers was "more severe" than expected, say researchers.

A new study looked at Canadians returning from trips to Zika-affected regions who sought treatment at a national network of travel clinics.

Researchers examined 1,118 patients who visited one of those clinics over a year.

They say they found a higher rate of complicated illness than anticipated in Zika patients.

The research was published on Monday in the the Canadian Medical Association Journal and the doctors behind the limited study say it underscores the importance of prevention.

The Canadian patients in the study visited one of seven travel clinics in British Columbia, Alberta, Manitoba, Ontario and Quebec between October 2015 and September 2016 and had travelled to Central and South America or the Caribbean.

Forty-one patients were diagnosed with Zika. Researchers found that 10% of patients with the virus had severe complications. None of the patients who came to the clinic with comparable tropical illnesses like dengue or chikungunya developed severe complications.

The most common symptoms that the Zika-infected travellers experienced were rash and fever followed by muscle or joint pain or headaches.

But of the three pregnant women who visited one of the clinics, two developed congenital infections that affected their babies.

Two patients showed symptoms of Guillain-Barré or GBS-like syndrome, which can cause temporary paralysis and has been linked to the infection, and one also had Zika viral meningitis.

Except for one case of infection through sexual intercourse, Zika cases that were part of the study were most likely transmitted by mosquitoes.

Dr Sumon Chakrabarti is an infectious disease expert at Trillium Health Partners, a Toronto-based hospital group, and was one of the researchers on the study.

He noted Canadians are "big travellers" to those regions and need to take steps to protect themselves from infection.

"We need to keep prevention in mind. Complications are rare but they exist," he said.

That means protecting against mosquito bites using clothing and a repellent with picaridin or DEET, and considering putting off travel to affected regions if you are pregnant or planning to become pregnant.

He also said it is important to wear condoms during sex if you or your partner travelled to one of the regions affected by the virus.

And Dr Chakrabarti said pregnant women whose partners have travelled to regions with Zika should use protection during sex for the full duration of the pregnancy.

The researchers did note the study was limited by its small size - the sample group made up only 12% of Canadians who contracted Zika virus over that time period.

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