Zika virus was initially introduced to the Americas in 2013, with widespread transmission occurring since late 2015.
The study was published in the Canadian Medical Association Journal last week and those involved claimed that its findings highlight the importance of prevention. They analysed Canadian travellers who had returned from the Americas and presented for care of Zika virus they had acquired to a CanTravNet site, between October 2015 and September 2016. The seven travel clinics in question were located in British Columbia, Alberta, Manitoba, Ontario and Quebec. During this time, 1,118 travellers presented to a CanTravNet site after their return from the Americas, 41, or 3.7 per cent, of whom had Zika infection.
This infection was diagnosed as often as dengue over the study period. While in the earlier half of this time period, Zika virus was contracted predominantly by people visiting friends or relatives in South America, the second half, which coincided with the spread of Zika in the Caribbean and Central America, saw Zika virus occur more to Caribbean tourists. The Zika-infected travellers most commonly experienced symptoms such as rash and fever, in addition to muscle or joint pain or headaches.
Ninety eight per cent of the travellers with Zika infection had acquired it most likely through mosquito exposure, while there was one confirmed case of sexual acquisition. Resulting congenital transmission occurred in two of three pregnancies. Two of the Zika patients had symptoms that resembled Guillain–Barré syndrome, one of whom was also found to have Zika viral meningitis. Although the doctors involved in the research admitted that they were using a small cohort, the sample group made up only 12 per cent of Canadians who contracted Zika virus over this timeframe, they claimed to have observed the entire clinical spectrum of acute Zika virus, which included adverse fetal and neurologic outcomes. They suggested that complications from Zika infection could be underestimated when only using data arising from populations where Zika is endemic. As Canadians popularly travel to the Americas, they were warned to adhere to mosquito avoidance measures and to use protection during sexual activity.