Prospective Analysis of Parasitic Infections in Canadian Travelers and Immigrants

BACKGROUND: International travel is associated with increased risk of vector-borne illnesses, particularly malaria. The objective of this study was to prospectively assess the relative frequency of parasitic diseases in Canadian travelers and to characterize demographic and travel-related predictors of these infections. METHODS: Data on Canadians and new immigrants who crossed international borders and were seen in the Tropical Disease Unit of Toronto General Hospital between November 1997 and June 2003 were prospectively collected and entered into the GeoSentinel Surveillance Network database. RESULTS: Of 3,528 returned Canadian travelers and new immigrants in the database, 1,010 had a parasitic infection diagnosed. Mean age of the 3,528 travelers was 37.3 years, and 42.6% were male. Those diagnosed with parasitic infections were more likely than the remaining cohort to have been traveling for the purpose of immigration (21.1% vs 7.1%, p < 0.001), or visiting friends and relatives (VFR) (17.9% vs 11.8%, p < 0.01). Common parasitic infections included nonhistolytica amebiasis (N= 209), malaria (N= 143), cutaneous larva migrans (N= 105), giardiasis (N= 74), and schistosomiasis (N= 48). CONCLUSIONS: Parasitic infections occurred in 29% of Canadian travelers. New immigrants and VFRs are at increased risk for malaria, as well as protozoal and helminthic infections.