Surveillance report of Zika virus among Canadian travellers returning from the Americas.

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.

Severe malaria in Canada, 2001-2013.

BACKGROUND: Imported malaria is the principal, preventable, life-threatening infection among Canadians travelling abroad. The Canadian Malaria Network supplies information and parenteral malaria therapy to healthcare providers treating severe and complicated malaria and gathers surveillance information on these cases. METHODS: Data were collected on the characteristics, risk factors, and clinical outcomes of severe malaria cases in Canada from June 2001 to December 2013. RESULTS: The need for parenteral therapy in Canada has increased in the last decade. The vast majority of cases are reported from Ontario and Quebec and occur among travellers to and from Africa. Regardless of country of birth, all persons originating from endemic and non-endemic countries are at a similar risk of malaria-related complications. Overall use and appropriateness of pre-travel advice and chemoprophylaxis remains low. Most cases result from patient delays in recognizing symptoms and seeking appropriate medical attention. Although some healthcare delays occurred in a select number of cases, the majority of patients were diagnosed quickly and were appropriately treated with parenteral therapy within a few hours of diagnosis. CONCLUSIONS: Data from the Canadian Malaria Network provide insight into the characteristics of imported severe and complicated malaria infections in Canada. Improved understanding of this population can help target risk reduction strategies and interventions to limit personal susceptibility and healthcare treatment delays.

Spectrum of illness in migrants to Canada: sentinel surveillance through CanTravNet.

BACKGROUND: Due to ongoing political instability and conflict in many parts of the world, migrants are increasingly seeking asylum and refuge in Canada. METHODS: We examined demographic and travel correlates of illnesses among migrants to Canada to establish a detailed epidemiologic framework of this population for Canadian practitioners. Data on ill-returned Canadian travellers presenting to a CanTravNet site between 1 January 2015 and 31 December 2015 were analyzed. RESULTS: During the study period, 2415 ill travellers and migrants presented to a CanTravNet site, and of those, 519 (21.5%) travelled for the purpose of migration. Sub-Saharan Africa (n = 160, 30.8%), southeast Asia (n = 84, 16.2%) and south central Asia (n = 75, 14.5%) were the most common source regions for migrants, while the top specific source countries, of 98 represented, were the Philippines (n = 45, 8.7%), China (n = 36, 6.9%) and Vietnam (n = 31, 6.0%). Compared with non-migrant travellers, migrants were more likely to have a pre-existing immunocompromising medical condition, such as HIV or diabetes mellitus (P < 0.0001), and to require inpatient management of their illness (P < 0.0001). Diagnoses such as tuberculosis (n = 263, 50.7%), hepatitis B and C (n = 78, 15%) and HIV (n = 11, 2.1%) were over-represented in the migrant population compared with non-migrant travellers (P < 0.0001). Most cases of tuberculosis in the migrant population (n = 263) were latent (82% [n = 216]); only 18% (n = 47) were active. CONCLUSIONS: Compared with non-migrant travellers, migrants were more likely to present with a communicable infectious disease, such as tuberculosis, potentially complicated by an underlying immunosuppressing condition such as HIV. These differences highlight the divergent healthcare needs in the migrant population, and underscore the importance of surveillance programmes to understand their burden of illness. Intake programming should be adequately resourced to accommodate the medical needs of this vulnerable population of new Canadians.

The changing landscape of travel health services in Canada.

Canadians are increasingly travelling to areas that would necessitate a pre-travel consultation. Changes in professional regulations in Canada allow greater autonomy of nurses and pharmacists, resulting in shifts in provision of travel health services. We surveyed 824 Canadian travel clinics, 270 (33%) of whom responded. Private clinics were most common, and more likely to offer extended hours and drop-in appointments. In one province, pharmacies dominated. Half the services were relatively new and a similar proportion saw fewer than 10 patients weekly; 1/3 had a single provider. The increased spectrum of services may increase convenience for travellers but the large proportion seeing low numbers of clients will challenge providers to maintain competence.

Malaria in travellers returning or migrating to Canada: surveillance report from CanTravNet surveillance data, 2004-2014.

BACKGROUND: Malaria remains the most common specific cause of fever in returned travellers and can be life-threatening. We examined demographic and travel correlates of malaria among Canadian travellers and immigrants to identify groups for targeted pretravel intervention. METHODS: Descriptive data on ill returned Canadian travellers and immigrants presenting to a CanTravNet site between 2004 and 2014 with a diagnosis of malaria were analyzed. Data were collected using the GeoSentinel data platform. This network comprises 63 specialized travel and tropical medicine clinics, including 7 Canadian sites (Vancouver, Calgary, Toronto, Ottawa, Winnipeg and Montréal), that contribute anonymous, delinked, clinician- and questionnaire-based travel surveillance data on all ill travellers examined to a centralized Structure Query Language database. RESULTS: During the study period, 20 345 travellers and immigrants were evaluated, and 93% had a travel-related diagnosis. Of these, 437 (2.1%) patients received 456 malaria diagnoses, the most common species being Plasmodium falciparum (n = 282, 61.8%). People travelling to visit friends and relatives were most well-represented (n = 169, 38.7%), followed by business travellers (n = 71, 16.2%). Sub-Saharan Africa was the most common source region, accounting for 341 (74.8%) malaria diagnoses, followed by South Central Asia (n = 55, 12%). Nigeria was the most well-represented source country, accounting for 41 cases (9.0%). India, a high-volume destination for Canadians, accounted for 40 cases (8.8%), 36 of which were caused by Plasmodium vivax. Of 456 malaria diagnoses, 26 (5.7%) were severe. Of 377 nonimmigrant travellers with malaria, 19.9% (n = 75) travelled for less than 2 weeks, and 7.2% (n = 27) travelled for less than 1 week. INTERPRETATION: This analysis provides an epidemiologic framework for Canadian practitioners encountering prospective and returned travellers. It confirms the importance of preventive measures and surveillance associated with travel to sub-Saharan Africa and India, particularly by travellers visiting friends or relatives. Short-duration travel confers important malaria risk.

Dermatoses among returned Canadian travellers and immigrants: surveillance report based on CanTravNet data, 2009-2012.

BACKGROUND: There is a lack of multicentre analyses of the spectrum of dermatologic illnesses acquired by Canadian travellers and immigrants. Our objective for this study was to provide a comprehensive, Canada-specific surveillance summary of travel-related dermatologic conditions in a cohort of returned Canadian travellers and immigrants. METHODS: Data for Canadian travellers and immigrants with a primary dermatologic diagnosis presenting to CanTravNet sites between September 2009 and September 2012 were extracted and analyzed. Data were collected using the GeoSentinel data platform. This network comprises 56 specialized travel and tropical medicine clinics, including 6 Canadian sites (Vancouver, Calgary, Toronto, Ottawa and Montréal), that contribute anonymous, de-linked, clinician- and questionnaire-based travel surveillance data on all ill travellers examined to a centralized Structure Query Language database. Results were analyzed according to reason for most recent ravel: immigration (including refugee); tourism; business; missionary/volunteer/research and aid work; visiting friends and relatives; and other, which included students, military personnel and medical tourists. RESULTS: During the study period, 6639 patients presented to CanTravNet sites across Canada and 1076 (16.2%) received a travel-related primary dermatologic diagnosis. Arthropod bites (n = 162, 21.5%), rash (n = 141, 18.7%), cutaneous larva migrans (n = 98, 13.0%), and skin and soft tissue infection (n = 92, 12.2%) were the most common dermatologic diagnoses or diagnostic bundles issued to returning Canadian tourists (n = 754, 70.1% of total sample). Patients travelling for the purpose of immigration (n = 63, 5.9%) were significantly more likely to require inpatient management of their dermatologic diagnoses (p < 0.001) than those travelling for other purposes. INTERPRETATION: This analysis of surveillance data details the spectrum of travel-related dermatological conditions among returning Canadian travellers in this cohort, and provides an epidemiologic framework for Canadian physicians encountering these patients.

Travel-acquired infections and illnesses in Canadians: surveillance report from CanTravNet surveillance data, 2009-2011.

BACKGROUND: Important knowledge gaps exist in our understanding of migration medicine practice and the impact of pathogens imported by Canadian travellers. We present here a comprehensive, Canada-specific surveillance summary of illness in a cohort of returned Canadian travellers and new immigrants. METHODS: We extracted and analyzed (using standard parametric and nonparametric techniques) data from the Canadian Travel Medicine Network (CanTravNet) database for ill returned Canadian travellers and new immigrants who presented to a Canadian GeoSentinel Surveillance Network site between September 2009 and September 2011. RESULTS: During the study period, 4365 travellers and immigrants presented to a CanTravNet site, 3943 (90.3%) of whom were assigned a travel-related diagnosis. Among the 3115 non-immigrant travellers with a definitive travel-related diagnosis, arthropod bite (n = 127 [4.1%]), giardiasis (n = 91 [2.9%]), malaria (n = 77 [2.5%]), latent tuberculosis (n = 73 [2.3%]), and strongyloidiasis (n = 66 [2.1%]) were the most common specific etiologic diagnoses. Among the 828 immigrants with definitive travel-related diagnoses, the most frequent etiologies were latent tuberculosis (n = 229 [27.7%]), chronic hepatitis B (n = 182 [22.0%]), active tuberculosis (n = 97 [11.7%]), chronic hepatitis C (n = 89 [10.7%]), and strongyloidiasis (n = 41 [5.0%]). Potentially serious infections, such as dengue fever (61 cases) and enteric fever due to Salmonella enterica serotype Typhi or Paratyphi (36 cases), were common. Individuals travelling for the purpose of visiting friends and relatives (n = 500 [11.6% of those with known reason for travel]) were over-represented among those diagnosed with malaria and enteric fever, compared with other illnesses (for malaria 34/94 [36.2%] v. 466/4221 [11.0%]; for enteric fever, 17/36 [47.2%] v. 483/4279 [11.3%]) (both p < 0.001). For cases of malaria, there was also overrepresentation (compared with other illnesses) from business travellers (22/94 [23.4%] v. 337/4221 [8.0%]) and males (62/94 [66.0%] v. 1964/4269 [46.0%]) (both p < 0.001). Malaria was more likely than other illnesses to be acquired in sub-Saharan Africa (p < 0.001), whereas dengue was more likely than other illnesses to be imported from the Caribbean and South East Asia (both p = 0.003) and enteric fever from South Central Asia (24/36 [66.7%]) (p < 0.001). INTERPRETATION: This analysis of surveillance data on ill returned Canadian travellers has detailed the spectrum of imported illness within this cohort. It provides an epidemiologic framework for Canadian practitioners encountering ill returned travellers. We have confirmed that travel to visit friends and relatives confers particularly high risks, which underscores the need to improve pretravel intervention for a population that is unlikely to seek specific pretravel advice. Potentially serious and fatal illnesses such as malaria and enteric fever were common, as were illnesses of public health importance, such as tuberculosis and hepatitis B.

Epidemiology of HIV in the United States and Canada: current status and ongoing challenges.

PURPOSE: To determine the status of the HIV epidemic in the United States and Canada. METHODS: We used data on AIDS and HIV diagnoses for 1996-2005 reported to the United States and Canadian national surveillance systems to determine trends in AIDS and HIV (33 US states only) diagnoses and to identify population groups most affected by HIV. HIV incidence for Canada was determined using back-calculation methods. We also determined the proportion of persons diagnosed late (HIV diagnosis within 12 months before AIDS diagnosis). RESULTS: AIDS diagnosis rates were higher in 2005 among blacks (54.1 per 100,000) and Hispanics (18.0) compared with whites (5.9) in the United States and among blacks (4.7) and aboriginal peoples (4.9) compared with whites (0.7) in Canada. Since 2001, HIV diagnoses increased among men who have sex with men in both countries and in Canada, increased among persons from HIV-endemic countries and where heterosexual contact was the only identified risk of transmission. Overall, HIV incidence remained relatively stable in Canada during that period. A large proportion of persons were diagnosed late in the disease process (United States, 54.3%; Canada, 64.2%). CONCLUSIONS: Rates of HIV transmission remain a challenge in both the United States and Canada as overall diagnosis rates have not decreased in recent years. Renewed prevention efforts are needed to further reduce the high HIV diagnosis rates among racial/ethnic minorities and to decrease HIV transmission among men who have sex with men.

Reemergence of the HIV epidemic among men who have sex with men in North America, Western Europe, and Australia, 1996-2005.

PURPOSE: To describe and contextualize changes in rates of human immunodeficiency virus (HIV) notifications in men who have sex with men (MSM) in eight countries (Australia, Canada, France, Germany, Netherlands, Spain, United Kingdom, and United States) from 1996-2005. METHODS: We analyzed trends in HIV notification rates from 1996-2000 and 2000-2005 by generalized linear regression and estimated annual percentage change (EAPC) in rates of HIV notifications. To interpret trends, we visually examined graphs of primary and secondary syphilis reports among MSM and the prevalence of recent HIV testing. RESULTS: The rate of HIV notifications among MSM declined 5.2% per year (95% confidence interval [CI]: -5.8%, -4.7%) from 1996-2000, and increased 3.3% per year (95% CI: +2.9%,+3.7%) from 2000-2005. During the period of increasing HIV diagnoses, increases in primary and secondary syphilis diagnoses occurred among MSM, but recent HIV testing among MSM did not seem to increase. CONCLUSIONS: After declining in the second half of the 1990s, HIV notification rates for MSM increased beginning in 2000. Increased HIV notifications in MSM are not wholly explained by changes in HIV testing. Urgent efforts are required to develop effective HIV prevention interventions for MSM, and implement them broadly in these countries.

Combining data sources to monitor the HIV epidemic in Canada.

This article describes the methods, results and future perspectives of four information sources used to monitor the HIV epidemic in Canada: AIDS case surveillance, HIV case surveillance, HIV sentinel serosurveillance, and behavioral surveillance. Synthesizing data from these multiple sources provides a more comprehensive picture of the HIV epidemic than any one source alone could provide. In Canada, there has been a shift over time from an epidemic dominated by men who have sex with men to one where more than half of new infections are attributed to other groups, such as injection drug users and non-injecting heterosexuals. The available evidence also suggests increasing HIV infections among Aboriginal persons and among women. Surveillance data have been used in Canada to guide prevention and care programs and to formulate policy. In particular, these data have been used to support the development of an HIV testing program in pregnancy, to re-direct community work toward injection drug users and the young, and to demonstrate the effectiveness of new treatments for HIV. The main challenge now is to continue to improve the monitoring of the shifting HIV epidemic with more accurate data and to use the resulting information to inform appropriate prevention and care responses.