Surveillance report of Zika virus among Canadian travellers returning from the Americas
Andrea K Boggild1, Jennifer Geduld2, Michael Libman2
1Department of Medicine (Boggild, Chakrabarti, Kain), Tropical Disease Unit, Division of Infectious Diseases, University Health Network and University of Toronto; Public Health Ontario Laboratories (Boggild), Public Health Ontario, Toronto, Ont.; Office of Border and Travel Health (Geduld), Public Health Agency of Canada, Ottawa, Ont.; The J.D. MacLean Centre for Tropical Diseases (Libman, Yansouni), McGill University, Montréal, Que.; Tropical Medicine and International Health Clinic (McCarthy), Division of Infectious Diseases, Ottawa Hospital and University of Ottawa, Ottawa, Ont.; Division of Infectious Diseases (Hajek, Mirzanejad), University of British Columbia, Vancouver, BC; Infectious Diseases (Ghesquiere), Vancouver Island Health Authority, Victoria, BC; Department of Medicine (Ghesquiere), University of British Columbia, Vancouver, BC; Fraser Health (Mirzanejad), Surrey, BC; Hôpital Saint-Luc du CHUM (Vincelette), Université de Montréal, Montréal, Que.; Departments of Pediatrics and Medicine (Kuhn), Section of Pediatric Infectious Diseases, Alberta Children's Hospital and University of Calgary, Calgary, Alta.; Travel Health and Tropical Medicine Services (Plourde), Population and Public Health Program, Winnipeg Regional Health Authority, Winnipeg, Man.; Trillium Health Partners (Chakrabarti), Mississauga, Ont.; Department of Medicine (Freedman), Center for Geographic Medicine, University of Alabama Birmingham, Birmingham, Ala.; SAR Laboratories (Kain), Sandra Rotman Centre, Toronto, Ont. andrea.boggild@utoronto.ca.
Background:
Widespread transmission of Zika virus in the Americas has occurred since late 2015. We examined demographic and travel-related characteristics of returned Canadian travellers with Zika infection acquired in the Americas to illuminate risk factors for acquisition and the clinical spectrum.
Methods:
We analyzed demographic and travel-related data for returned Canadian travellers who presented to a CanTravNet site between October 2015 and September 2016 for care of Zika virus acquired in the Americas. Data were collected with use of the GeoSentinel Surveillance Network data platform.
Results:
During the study period, 1118 travellers presented to a CanTravNet site after returning from the Americas, 41 (3.7%) of whom had Zika infection. Zika infection from the Americas was diagnosed at CanTravNet sites as often as dengue (n = 41) over the study period. In the first half of the study period, Zika virus burden was borne by people visiting friends and relatives in South America. In the latter half, coincident with the increased spread of Zika throughout the Caribbean and Central America, Zika virus occurred more often in tourists in the Caribbean. Forty (98%) of the travellers with Zika infection acquired it through probable mosquito exposure, and 1 had confirmed sexual acquisition. Congenital transmission occurred in 2 of 3 pregnancies. Two (5%) of those with Zika had symptoms resembling those of Guillain-Barré syndrome, 1 of whom also had Zika viral meningitis.
Interpretation:
Even in this small cohort, we observed the full clinical spectrum of acute Zika virus, including adverse fetal and neurologic outcomes. Our observations suggest that complications from Zika infection are underestimated by data arising exclusively from populations where Zika is endemic. Travellers should adhere to mosquito-avoidance measures and barrier protection during sexual activity.
