Travel-acquired infections in Canada: CanTravNet 2011-2012

Tracing the History of Hepatitis E Virus Infection in Mexico: From the Enigmatic Genotype 2 to the Current Disease Situation

Hepatitis E virus (HEV) is the major cause of acute viral hepatitis worldwide. This virus is responsible for waterborne outbreaks in low-income countries and zoonosis transmission in industrialized regions. Initially, considered self-limiting, HEV may also lead to chronic disease, and evidence supports that infection can be considered a systemic disease. In the late 1980s, Mexico became a hot spot in the study of HEV due to one of the first virus outbreaks in Latin America related to enterically transmitted viral non-A, non-B hepatitis. Viral stool particles recovered from Mexican viral hepatitis outbreaks represented the first identification of HEV genotype (Gt) 2 (Gt2) in the world. No new findings of HEV-Gt2 have been reported in the country, whereas this genotype has been found in countries on the African continent. Recent investigations in Mexico have identified other strains (HEV-Gt1 and -Gt3) and a high frequency of anti-HEV antibodies in animal and human populations. Herein, the potential reasons for the disappearance of HEV-Gt2 in Mexico and the advances in the study of HEV in the country are discussed along with challenges in studying this neglected pathogen. These pieces of information are expected to contribute to disease control in the entire Latin American region.

Non-Endemic Leishmaniases Reported Globally in Humans between 2000 and 2021—A Comprehensive Review

Leishmaniases are human and animal parasitic diseases transmitted by phlebotomine sand flies. Globalization is an important driver of the burden and in the current dynamics of these diseases. A systematic review of articles published between 2000 and 2021 was conducted using the PubMed search engine to identify the epidemiology and clinical management of imported human leishmaniases as a fundamental step to better manage individual cases and traveler and migrant health from a global perspective. A total of 275 articles were selected, representing 10,341 human imported cases. Identified drivers of changing patterns in epidemiology include conflict and war, as well as host factors, such as immunosuppression, natural and iatrogenic. Leishmania species diversity associated with different clinical presentations implies diagnostic and treatment strategies often complex to select and apply, especially in non-endemic settings. Thus, diagnostic and management algorithms for medical clinical decision support are proposed. Increased surveillance of non-endemic cases, whether in vulnerable populations such as refugees/migrants and immunocompromised individuals or travelers, could improve individual health and mitigate the public health risk of introducing Leishmania species into new areas.

Aetiology of fever in returning travellers and migrants: a systematic review and meta-analysis

BACKGROUND

Numerous publications focus on fever in returning travellers, but there is no known systematic review considering all diseases, or all tropical diseases causing fever. Such a review is necessary in order to develop appropriate practice guidelines.

OBJECTIVES

Primary objectives of this review were (i) to determine the aetiology of fever in travellers/migrants returning from (sub) tropical countries as well as the proportion of patients with specific diagnoses, and (ii) to assess the predictors for specific tropical diseases.

METHOD

Embase, MEDLINE and Cochrane Library were searched with terms combining fever and travel/migrants. All studies focusing on causes of fever in returning travellers and/or clinical and laboratory predictors of tropical diseases were included. Meta-analyses were performed on frequencies of etiological diagnoses.

RESULTS

10 064 studies were identified; 541 underwent full-text review; 30 met criteria for data extraction. Tropical infections accounted for 33% of fever diagnoses, with malaria causing 22%, dengue 5% and enteric fever 2%. Non-tropical infections accounted for 36% of febrile cases, with acute gastroenteritis causing 14% and respiratory tract infections 13%. Positive likelihood ratios demonstrated that splenomegaly, thrombocytopenia and hyperbilirubinemia were respectively 5-14, 3-11 and 5-7 times more likely in malaria than non-malaria patients. High variability of results between studies reflects heterogeneity in study design, regions visited, participants' characteristics, setting, laboratory investigations performed and diseases included.

CONCLUSION

Malaria accounted for one-fifth of febrile cases, highlighting the importance of rapid malaria testing in febrile returning travellers, followed by other rapid tests for common tropical diseases. High variability between studies highlights the need to harmonize study designs and to promote multi-centre studies investigating predictors of diseases, including of lower incidence, which may help to develop evidence-based guidelines. The use of clinical decision support algorithms by health workers which incorporate clinical predictors, could help standardize studies as well as improve quality of recommendations.

Social, Clinical, and Behavioral Determinants of HIV Infection and HIV Testing among Black Men in Toronto, Ontario: A Classification and Regression Tree Analysis

Black men bear a disproportionate burden of HIV infection. These HIV inequities are influenced by intersecting social, clinical, and behavioral factors. The purpose of this analysis was to determine the combinations of factors that were most predictive of HIV infection and HIV testing among black men in Toronto. Classification and regression tree analysis was applied to secondary data collected from black men (N = 460) in Toronto, 82% of whom only had sex with women and 18% whom had sex with men at least once. For HIV infection, 10 subgroups were identified and characterized by number of lifetime male partners, age, syphilis history, and perceived stigma. Number of lifetime male partners was the best single predictor of HIV infection. For HIV testing, the analysis identified 8 subgroups characterized by age, condom use, number of sex partners and Chlamydia history. Age (>24 years old) was the best single predictor of HIV testing.

2018 in review: five hot topics in tropical medicine

The year 2018 heralded many new developments in the field of tropical medicine, including licensure of novel drugs for novel indications, licensure of existing drugs for existing indications but in novel settings, and globalized outbreaks of both vector-borne and zoonotic diseases. We herein describe five top stories in tropical medicine that occurred during 2018, and illuminate the practice-changing development within each story.

Could exotic mosquito-borne diseases emerge in Canada with climate change?

Of the 3,500 species of mosquitoes worldwide, only a small portion carry and transmit the mosquito-borne diseases (MBDs) that cause approximately half a million deaths annually worldwide. The most common exotic MBDs, such as malaria and dengue, are not currently established in Canada, in part because of our relatively harsh climate; however, this situation could evolve with climate change. Mosquitoes native to Canada may become infected with new pathogens and move into new regions within Canada. In addition, new mosquito species may move into Canada from other countries, and these exotic species may bring exotic MBDs as well. With high levels of international travel, including to locations with exotic MBDs, there will be more travel-acquired cases of MBDs. With climate change, there is the potential for exotic mosquito populations to become established in Canada. There is already a small area of Canada where exotic Aedes mosquitoes have become established although, to date, there is no evidence that these carry any exotic (or already endemic) MBDs. The increased risks of spreading MBDs, or introducing exotic MBDs, will need a careful clinical and public health response. Clinicians will need to maintain a high level of awareness of current trends, to promote mosquito bite prevention strategies, and to know the laboratory tests needed for early detection and when to report laboratory results to public health. Public health efforts will need to focus on ongoing active surveillance, public and professional awareness and mosquito control. Canadians need to be aware of the risks of acquiring exotic MBDs while travelling abroad as well as the risk that they could serve as a potential route of introduction for exotic MBDs into Canada when they return home.

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.

Spectrum of Viral Pathogens in Blood of Malaria-Free Ill Travelers Returning to Canada

Malaria is the most common specific cause of fever in returning travelers, but many other vectorborne infections and viral infections are emerging and increasingly encountered by travelers. We documented common and emerging viral pathogens in malaria-negative specimens from ill travelers returning to Canada. Anonymized, malaria-negative specimens were examined for various viral pathogens by real-time PCR. Samples were positive for herpes simplex viruses 1 or 2 (n = 21, 1.6%), cytomegalovirus (n = 4, 0.3%), Epstein-Barr virus (n = 194, 14.9%), dengue virus types 1-4 (n = 27, 2.1%), chikungunya virus (n = 5, 0.4%), and hepatitis A virus (n = 12, 0.9%). Travel-acquired viral pathogens were documented in >20% of malaria-negative specimens, of which 2.5% were infected with dengue and chikungunya viruses. Our findings support the anecdotal impression that these vectorborne pathogens are emerging among persons who travel from Canada to other countries.

Illness in Canadian travellers and migrants from Brazil: CanTravNet surveillance data, 2013-2016

Background

In light of the 2016 summer Olympic games it is anticipated that Canadian practitioners will require information about common illnesses that may affect travellers returning from Brazil.

Objective

To identify the demographic and travel correlates of illness among recent Canadian travellers and migrants from Brazil attending a network of travel health clinics across Canada.

Methods

Data was analyzed on returned Canadian travellers and migrants presenting to a CanTravNet site for care of an illness between June 2013 and June 2016.

Results

During the study period, 7,707 ill travellers and migrants presented to a CanTravNet site and 89 (0.01%) acquired their illness in Brazil. Tourists were most well represented (n=45, 50.6%), followed by those travelling to "visit friends and relatives" (n=14, 15.7%). The median age was 37 years (range <1-78 years), 49 travellers were men (55.1%) and 40 were women (44.9%). Of the 40 women, 26 (65%) were of childbearing age. Nine percent (n=8) of travellers were diagnosed with arboviruses including dengue (n=6), chikungunya (n=1) and Zika virus (n=1), while another 14.6% (n=13) presented for care of non-specific viral syndrome (n=7), non-specific febrile illness (n=1), peripheral neuropathy (n=1) and non-specific rash (n=4), which are four syndromes that may be indicative of Zika virus infection. Ill returned travellers to Brazil were more likely to present for care of arboviral or Zika-like illness than other ill returned travellers to South America (23.6 per 100 travellers versus 10.5 per 100 travellers, respectively [p=0.0024]).

Interpretation

An epidemiologic approach to illness among returned Canadian travellers to Brazil can inform Canadian practitioners encountering both prospective and returned travellers to the Olympic games. Analysis showed that vector-borne illnesses such as dengue are common and even in this small group of travellers, both chikungunya and Zika virus were represented. It is extremely important to educate travellers about mosquito-avoidance measures in advance of travel to Brazil.

Evaluation of a programme for 'Rapid Assessment of Febrile Travelers' (RAFT): a clinic-based quality improvement initiative

BACKGROUND

Fever in the returned traveller is a potential medical emergency warranting prompt attention to exclude life-threatening illnesses. However, prolonged evaluation in the emergency department (ED) may not be required for all patients. As a quality improvement initiative, we implemented an algorithm for rapid assessment of febrile travelers (RAFT) in an ambulatory setting.

METHODS

Criteria for RAFT referral include: presentation to the ED, reported fever and travel to the tropics or subtropics within the past year. Exclusion criteria include Plasmodium falciparum malaria, and fulfilment of admission criteria such as unstable vital signs or significant laboratory derangements. We performed a time series analysis preimplementation and postimplementation, with primary outcome of wait time to tropical medicine consultation. Secondary outcomes included number of ED visits averted for repeat malaria testing, and algorithm adherence.

RESULTS

From February 2014 to December 2015, 154 patients were seen in the RAFT clinic: 68 men and 86 women. Median age was 36 years (range 16-78 years). Mean time to RAFT clinic assessment was 1.2±0.07 days (range 0-4 days) postimplementation, compared to 5.4±1.8 days (range 0-26 days) prior to implementation (p<0.0001). The RAFT clinic averted 132 repeat malaria screens in the ED over the study period (average 6 per month). Common diagnoses were: traveller's diarrhoea (n=27, 17.5%), dengue (n=12, 8%), viral upper respiratory tract infection (n=11, 7%), chikungunya (n=10, 6.5%), laboratory-confirmed influenza (n=8, 5%) and lobar pneumonia (n=8, 5%).

CONCLUSIONS

In addition to provision of more timely care to ambulatory febrile returned travellers, we reduced ED bed-usage by providing an alternate setting for follow-up malaria screening, and treatment of infectious diseases manageable in an outpatient setting, but requiring specific therapy.

CATMAT statement on disseminated strongyloidiasis: Prevention, assessment and management guidelines

Background

Strongyloides stercoralis is a parasitic nematode found in humans, with a higher prevalence in tropical and sub-tropical regions worldwide. If untreated, the infection can progress to disseminated strongyloidiasis, a critical illness which may be fatal.

Objective

To provide clinical guidance on the prevention, assessment and management of disseminated strongyloidiasis.

Methods

A literature review was conducted to evaluate the current evidence and to identify any systematic reviews, case reports, guidelines and peer reviewed and non-peer reviewed medical literature. The Committee to Advise on Tropical Medicine and Travel (CATMAT) assembled a working group to develop this statement, which was then critically reviewed and approved by all CATMAT members.

Recommendations

CATMAT recommends that screening for strongyloidiasis should be considered for individuals with epidemiologic risk and/or co-morbidities that place them at risk for Strongyloides hyperinfection and dissemination. Those at highest risk of hyperinfection and dissemination are individuals born in a Strongyloides-endemic area who undergo iatrogenic immunosuppression or have intercurrent human T-lymphotropic virus (HTLV-1) infection. Diagnosis of strongyloidiasis is based on serologic testing and/or examination of stools and other clinical specimens for larvae. Referral to a tropical medicine specialist with expertise in the management of strongyloidiasis is recommended for suspected and confirmed cases. A diagnosis and treatment algorithm for strongyloidiasis has been developed as a reference tool.

Conclusion

Strongyloidiasis is relatively widespread in the global migrant population and screening for the disease should be based on an individual risk assessment. A practical tool for the clinician to use in the prevention, assessment and management of disseminated strongyloidiasis in Canada is now available.

Management of imported cutaneous larva migrans: A case series and mini-review

BACKGROUND

Cutaneous larva migrans (CLM), a zoonotic helminthiasis imported to Canada by travelers to the tropics, causes morbidity due to severe, intractable pruritus. Treatment in Canada is only available through the Special Access Program (SAP) of Health Canada, thus, many patients are prescribed ineffective courses of non-targeted therapy.

OBJECTIVE

We analyzed patients with CLM referred to our specialized Tropical Disease Unit (TDU) having failed non-targeted therapy prior to referral, and characterized demographic and travel related correlates of CLM.

METHODS

Patients with CLM evaluated between June 2012 and December 2014 were identified through our SAP application log, and charts were reviewed for demographic, clinical, and travel-related data following IRB approval.

RESULTS

25 patients with CLM were identified: 12 women, and 13 men. Median age was 35 years (range 4-58 years). Patients had primarily acquired their CLM in the Caribbean (80%), with Jamaica being the most well represented source destination (N = 10, 40%). Reported symptoms included intense, function-limiting pruritus (N = 25, 100%) and loss of sleep (N = 3, 12%). Twelve patients (48%) with CLM had received at least 1 course of non-targeted therapy prior to referral. Non-targeted therapies included topical steroids (N = 7), cryotherapy (N = 3), oral antibiotics (N = 2), and oral mebendazole (N = 11). Median duration of symptoms was 34 days (range 5-226 days). Of 25 patients with CLM, 23 (92%) were prescribed a single 3-day course of albendazole and responded appropriately, and 2 (8%) required a second 3-day course of albendazole.

CONCLUSIONS

Although CLM is non-communicable and of little public health relevance in Canada, it causes significant morbidity. A substantial proportion of patients with CLM referred to our specialized TDU had a prolonged course of illness and were prescribed ineffective and non-targeted therapies. Oral albendazole or ivermectin, or topical thiabendazole, are the drugs of choice for CLM, and should be prescribed as first-line therapy.

Fever in a visitor to Canada: a case of mistaken identity

We report a case of babesiosis in a traveler from India who was diagnosed with malaria on the basis of blood smears. Pan-Plasmodium PCR was positive, though species-specific assays were negative. Reexamination of blood smears and Babesia-specific PCR confirmed babesiosis. We highlight the overlapping clinical and diagnostic features of malaria and babesiosis and the potential cross-reactivity of Plasmodium primers in cases of babesiosis.