Acute and potentially life-threatening tropical diseases in western travelers--a GeoSentinel multicenter study, 1996-2011

[Update on leptospirosis]

Leptospirosis is a worldwide spirochetal zoonosis whose global incidence is increasing and is probably underestimated. Leptospirosis has long been associated with occupational contact with animals (rats and cattle) and has become in developed countries a pathology more related to recreational activities with exposure to fresh water (canoeing, swimming, canyoning) and to an environment contaminated by urine from leptospires excretory rodents. Leptospirosis should be one of the differential diagnoses to be considered when returning from travel to tropical areas, particularly Southeast Asia, and particularly during the rainy season. The clinical symptoms, particularly in the initial phase, are not specific and can limit to a flu-like syndrome or "dengue-like" making diagnosis often difficult. It is then necessary to look carefully for clinical (muscle pain, cough, conjunctival involvement, jaundice) and biological arguments (thrombocytopenia, cholestasis, rhabdomyolysis, frank elevation of CRP) that will help to diagnose leptospirosis and lead to quick antibiotic therapy before the progression to a severe icterohaemorrhagic (Weil's disease) or respiratory form associated with significant mortality. Treatment is based on injectable beta-lactams in severe forms (mainly cephalosporins) and amoxicillin, doxycycline or azithromycin in non-severe forms. Some atypical or delayed forms of leptospirosis occurring in the late immune phase of the disease are to know. Rapid diagnostic tools are currently being studied to improve diagnosis in remote areas and facilitate access to early treatment.

Leptospirosis among Returned Travelers: A GeoSentinel Site Survey and Multicenter Analysis-1997-2016

Leptospirosis is a potentially fatal emerging zoonosis with worldwide distribution and a broad range of clinical presentations and exposure risks. It typically affects vulnerable populations in (sub)tropical countries but is increasingly reported in travelers as well. Diagnostic methods are cumbersome and require further improvement. Here, we describe leptospirosis among travelers presenting to the GeoSentinel Global Surveillance Network. We performed a descriptive analysis of leptospirosis cases reported in GeoSentinel from January 1997 through December 2016. We included 180 travelers with leptospirosis (mostly male; 74%; mostly tourists; 81%). The most frequent region of infection was Southeast Asia (52%); the most common source countries were Thailand (N = 52), Costa Rica (N = 13), Indonesia, and Laos (N = 11 each). Fifty-nine percent were hospitalized; one fatality was reported. We also distributed a supplemental survey to GeoSentinel sites to assess clinical and diagnostic practices. Of 56 GeoSentinel sites, three-quarters responded to the survey. Leptospirosis was reported to have been most frequently considered in febrile travelers with hepatic and renal abnormalities and a history of freshwater exposure. Serology was the most commonly used diagnostic method, although convalescent samples were reported to have been collected infrequently. Within GeoSentinel, leptospirosis was diagnosed mostly among international tourists and caused serious illness. Clinical suspicion and diagnostic workup among surveyed GeoSentinel clinicians were mainly triggered by a classical presentation and exposure history, possibly resulting in underdiagnosis. Suboptimal usage of available diagnostic methods may have resulted in additional missed, or misdiagnosed, cases.

Vaccines for preventing typhoid fever

BACKGROUND

Typhoid fever and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and southeast Asia. Two typhoid vaccines are widely available, Ty21a (oral) and Vi polysaccharide (parenteral). Newer typhoid conjugate vaccines are at varying stages of development and use. The World Health Organization has recently recommended a Vi tetanus toxoid (Vi-TT) conjugate vaccine, Typbar-TCV, as the preferred vaccine for all ages.

OBJECTIVES

To assess the effects of vaccines for preventing typhoid fever.

SEARCH METHODS

In February 2018, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, and mRCT. We also searched the reference lists of all included trials.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials (RCTs) comparing typhoid fever vaccines with other typhoid fever vaccines or with an inactive agent (placebo or vaccine for a different disease) in adults and children. Human challenge studies were not eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied inclusion criteria and extracted data, and assessed the certainty of the evidence using the GRADE approach. We computed vaccine efficacy per year of follow-up and cumulative three-year efficacy, stratifying for vaccine type and dose. The outcome addressed was typhoid fever, defined as isolation of Salmonella enterica serovar Typhi in blood. We calculated risk ratios (RRs) and efficacy (1 - RR as a percentage) with 95% confidence intervals (CIs).

MAIN RESULTS

In total, 18 RCTs contributed to the quantitative analysis in this review: 13 evaluated efficacy (Ty21a: 5 trials; Vi polysaccharide: 6 trials; Vi-rEPA: 1 trial; Vi-TT: 1 trial), and 9 reported on adverse events. All trials but one took place in typhoid-endemic countries. There was no information on vaccination in adults aged over 55 years of age, pregnant women, or travellers. Only one trial included data on children under two years of age.Ty21a vaccine (oral vaccine, three doses)A three-dose schedule of Ty21a vaccine probably prevents around half of typhoid cases during the first three years after vaccination (cumulative efficacy 2.5 to 3 years: 50%, 95% CI 35% to 61%, 4 trials, 235,239 participants, moderate-certainty evidence). These data include patients aged 3 to 44 years.Compared with placebo, this vaccine probably does not cause more vomiting, diarrhoea, nausea or abdominal pain (2 trials, 2066 participants; moderate-certainty evidence), headache, or rash (1 trial, 1190 participants; moderate-certainty evidence); however, fever (2 trials, 2066 participants; moderate-certainty evidence) is probably more common following vaccination.Vi polysaccharide vaccine (injection, one dose)A single dose of Vi polysaccharide vaccine prevents around two-thirds of typhoid cases in the first year after vaccination (year 1: 69%, 95% CI 63% to 74%; 3 trials, 99,979 participants; high-certainty evidence). In year 2, trial results were more variable, with the vaccine probably preventing between 45% and 69% of typhoid cases (year 2: 59%, 95% CI 45% to 69%; 4 trials, 194,969 participants; moderate-certainty evidence). These data included participants aged 2 to 55 years of age.The three-year cumulative efficacy of the vaccine may be around 55% (95% CI 30% to 70%; 11,384 participants, 1 trial; low-certainty evidence). These data came from a single trial conducted in South Africa in the 1980s in participants aged 5 to 15 years.Compared with placebo, this vaccine probably did not increase the incidence of fever (3 trials, 132,261 participants; moderate-certainty evidence) or erythema (3 trials, 132,261 participants; low-certainty evidence); however, swelling (3 trials, 1767 participants; moderate-certainty evidence) and pain at the injection site (1 trial, 667 participants; moderate-certainty evidence) were more common in the vaccine group.Vi-rEPA vaccine (two doses)Administration of two doses of the Vi-rEPA vaccine probably prevents between 50% and 96% of typhoid cases during the first two years after vaccination (year 1: 94%, 95% CI 75% to 99%; year 2: 87%, 95% CI 56% to 96%, 1 trial, 12,008 participants; moderate-certainty evidence). These data came from a single trial with children two to five years of age conducted in Vietnam.Compared with placebo, both the first and the second dose of this vaccine increased the risk of fever (1 trial, 12,008 and 11,091 participants, low-certainty evidence) and the second dose increase the incidence of swelling at the injection site (one trial, 11,091 participants, moderate-certainty evidence).Vi-TT vaccine (two doses)We are uncertain of the efficacy of administration of two doses of Vi-TT (PedaTyph) in typhoid cases in children during the first year after vaccination (year 1: 94%, 95% CI -1% to 100%, 1 trial, 1625 participants; very low-certainty evidence). These data come from a single cluster-randomized trial in children aged six months to 12 years and conducted in India. For single dose Vi-TT (Typbar-TCV), we found no efficacy trials evaluating the vaccine with natural exposure.There were no reported serious adverse effects in RCTs of any of the vaccines studied.

AUTHORS' CONCLUSIONS

The licensed Ty21a and Vi polysaccharide vaccines are efficacious in adults and children older than two years in endemic countries. The Vi-rEPA vaccine is just as efficacious, although data is only available for children. The new Vi-TT vaccine (PedaTyph) requires further evaluation to determine if it provides protection against typhoid fever. At the time of writing, there were only efficacy data from a human challenge setting in adults on the Vi-TT vaccine (Tybar), which clearly justify the ongoing field trials to evaluate vaccine efficacy.

Infectious diseases during the European Union training mission Mali (EUTM MLI) - a four-year experience

BACKGROUND

The European Union Training Mission Mali (EUTM MLI) is a multinational military training deployment to the Western African tropical nation of Mali. Based on routinely collected disease and non-battle injury surveillance data, this study quantifies the true impact of infectious diseases for this tropical mission and potential seasonal variations in infectious disease threats.

METHODS

Categorized health events during the EUTM MLI mission and associated lost working days were reported using the EpiNATO-2 report. Infection-related health events were descriptively analyzed for a 4-year period from the 12th week in 2013 to the 13th week in 2017. Aggregated EpiNATO-2 data collected from all missions other than EUTM MLI were used as a comparator.

RESULTS

Among the infectious diseases reported by EUTM MLI, non-severe upper respiratory infections and gastrointestinal diseases dominated quantitatively, accounting for 1.65 and 1.42 consultations per 100 person-weeks, respectively. The number of recorded infectious disease-associated lost working days during the whole study interval was 723. Seasonal changes in disease frequency were detectable. More gastrointestinal infections were seen in the rainy season, and more respiratory infections occurred in the dry season; these were associated with peaks of more than 2.5 consultations per 100 person-weeks for both categories.

CONCLUSIONS

Despite initial concerns focused on tropical infectious diseases during this mission in tropical Mali, upper respiratory tract and gastrointestinal infections predominate. The relatively low number of reported lost working days may indicate that these infections are at the milder end of the spectrum of infectious diseases despite a likely reporting bias.

Travel-related leptospirosis in the Netherlands 2009-2016: An epidemiological report and case series

BACKGROUND

Leptospirosis is a potentially fatal zoonotic disease that is prevalent in travellers. Here, we describe epidemiological and diagnostic characteristics of all returning travellers diagnosed with leptospirosis in the Netherlands between 2009 and 2016. Furthermore, we present a detailed clinical case series of all travellers with leptospirosis who presented at the Academic Medical Center (AMC) in the same period.

METHOD

We extracted data from the records of the Dutch Leptospirosis Reference Center (NRL) of all cases of leptospirosis in travellers in the Netherlands from 2009 to 2016. Patients who presented at the AMC were identified and clinical data were extracted from the hospital records.

RESULTS

224 cases of travel-related leptospirosis were included. An increase of cases was observed from 2014 onwards. The majority of cases were male (78.1%), and had travelled to South-East Asia (62.1%). Of 41 AMC cases, 53.7% were hospitalised, but most patients had a relatively mild disease course, with no fatalities. A longer delay in diagnosis and treatment initiation existed in hospitalised compared to non-hospitalised patients, suggesting a benefit of early recognition and treatment.

CONCLUSIONS

Leptospirosis was increasingly observed in returning travellers in the Netherlands, and is a diagnosis that should be considered in any returning febrile traveller.

Tropical diseases in the ICU: A syndromic approach to diagnosis and treatment

Tropical infections form 20-30% of ICU admissions in tropical countries. Diarrheal diseases, malaria, dengue, typhoid, rickettsial diseases and leptospirosis are common causes of critical illness. Overlapping clinical features makes initial diagnosis challenging. A systematic approach involving (1) history of specific continent or country of travel, (2) exposure to specific environments (forests or farms, water sports, consumption of exotic foods), (3) incubation period, and (4) pattern of organ involvement and subtle differences in manifestations help in differential diagnosis and choice of initial empiric therapy. Fever, rash, hypotension, thrombocytopenia and mild derangement of liver function tests is seen in a majority of patients. Organ failure may lead to shock, respiratory distress, renal failure, hepatitis, coma, seizures, cardiac arrhythmias or hemorrhage. Diagnosis in some conditions is made by peripheral blood smear examination, antigen detection or detection of microbial nucleic acid by PCR. Tests that detect specific IgM antibody become positive only in the second week of illness. Initial therapy is often empiric; a combination of intravenous artesunate, ceftriaxone and either doxycycline or azithromycin would cover a majority of the treatable syndromes. Additional antiviral or antiprotozoal medications are required for some specific syndromes. Involving a physician specializing in tropical or travel medicine is helpful.

Spotted Fever Rickettsiosis in a Wildlife Researcher in Sabah, Malaysia: A Case Study

We present evidence for a case of spotted fever rickettsiosis with severe complications in a young adult male. Although spotted fever group rickettsiae (SFGR) have been reported as the most prevalent cause of rickettsiosis in rural areas of Sabah, Malaysia since the 1980s, this is the first detailed case report of suspected SFGR in the state. Current data on the prevalence, type, and thorough clinical reports on complications of SFGR and other rickettsioses in Sabah is lacking and required to raise the awareness of such diseases. There is a need to emphasize the screening of rickettsioses to medical personnel and to encourage the use of appropriate antibiotics as early treatment for nonspecific febrile illnesses in this region. Suspected rickettsioses need to be considered as one of the differential diagnoses for patients presenting with acute febrile illness for laboratory investigations, and early treatment instituted.

Under-diagnosis of rickettsial disease in clinical practice: A systematic review

BACKGROUND

Rickettsial diseases present as acute febrile illnesses, sometimes with inoculation eschars.

METHODS

We performed a systematic review of studies published between 1997 and 2017 to assess the underestimation of non-eschar rickettsial disease (NERD) relative to eschar rickettsial disease (ERD), as a cause of acute fever in patients with rickettsial diseases that commonly present with eschar(s): scrub typhus (ST), Mediterranean spotted fever (MSF), and African tick-bite fever. We compared ERD/NERD ratios according to study design: 'complete approach' studies, with testing performed in all patients with 'unspecified febrile illness'; versus 'clinical judgement' studies, with testing performed if patients presented with specific symptoms.

RESULTS

In 'complete approach' studies, ERD/NERD ratios were significantly lower, suggesting a considerable under-diagnosis of NERD in 'clinical judgement' studies. Based on these results, we estimate that the diagnosis of rickettsial disease was missed in 66.5% of patients with ST, and in 57.9% of patients with MSF.

CONCLUSIONS

Study design influences the reported eschar rates in ST and MSF significantly. NERD is likely to be a vastly underdiagnosed entity, and clinicians should consider and test for the disease more often.

PROSPERO REGISTRATION NUMBER

CRD 42016053348.

Leptospirosis: Report from the task force on tropical diseases by the World Federation of Societies of Intensive and Critical Care Medicine

Leptospirosis is a zoonosis caused by a gram negative aerobic spirochete of the genus Leptospira. It is acquired by contact with urine or reproductive fluids from infected animals, or by inoculation from contaminated water or soil. The disease has a global distribution, mainly in tropical and subtropical regions that have a humid, rainy climate and is also common in travelers returning from these regions. Clinical suspicion is critical for the diagnosis and it should be included in the differential diagnosis of any patient with a febrile hepatorenal syndrome in, or returning from endemic regions. The leptospiremic phase occurs early and thereafter there is an immunologic phase in which the most severe form, Weil's disease, occurs. In the latter, multiple organ dysfunction predominates. The appropriate diagnostic test depends on the stage of the disease and consists of direct and indirect detection methods and cultures. Severely ill patients need to be monitored in an ICU with appropriate anti-bacterial agents and early, aggressive and effective organ support. Antibiotic therapy consists of penicillins, macrolides or third generation cephalosporins.

A comparison of two molecular methods for diagnosing leptospirosis from three different sample types in patients presenting with fever in Laos

OBJECTIVES

To compare two molecular assays (rrs quantitative PCR (qPCR) versus a combined 16SrRNA and LipL32 qPCR) on different sample types for diagnosing leptospirosis in febrile patients presenting to Mahosot Hospital, Vientiane, Laos.

METHODS

Serum, buffy coat and urine samples were collected on admission, and follow-up serum ∼10 days later. Leptospira spp. culture and microscopic agglutination tests (MAT) were performed as reference standards. Bayesian latent class modelling was performed to estimate sensitivity and specificity of each diagnostic test.

RESULTS

In all, 787 patients were included in the analysis: 4/787 (0.5%) were Leptospira culture positive, 30/787 (3.8%) were MAT positive, 76/787 (9.7%) were rrs qPCR positive and 20/787 (2.5%) were 16SrRNA/LipL32 qPCR positive for pathogenic Leptospira spp. in at least one sample. Estimated sensitivity and specificity (with 95% CI) of 16SrRNA/LipL32 qPCR on serum (53.9% (33.3%-81.8%); 99.6% (99.2%-100%)), buffy coat (58.8% (34.4%-90.9%); 99.9% (99.6%-100%)) and urine samples (45.0% (27.0%-66.7%); 99.6% (99.3%-100%)) were comparable with those of rrs qPCR, except specificity of 16SrRNA/LipL32 qPCR on urine samples was significantly higher (99.6% (99.3%-100%) vs. 92.5% (92.3%-92.8%), p <0.001). Sensitivities of MAT (16% (95% CI 6.3%-29.4%)) and culture (25% (95% CI 13.3%-44.4%)) were low. Mean positive Cq values showed that buffy coat samples were more frequently inhibitory to qPCR than either serum or urine (p <0.001).

CONCLUSIONS

Serum and urine are better samples for qPCR than buffy coat, and 16SrRNA/LipL32 qPCR performs better than rrs qPCR on urine. Quantitative PCR on admission is a reliable rapid diagnostic tool, performing better than MAT or culture, with significant implications for clinical and epidemiological investigations of this global neglected disease.

State of the art of diagnosis of rickettsial diseases: the use of blood specimens for diagnosis of scrub typhus, spotted fever group rickettsiosis, and murine typhus

PURPOSE OF REVIEW

With improved malaria control, acute undifferentiated febrile illness studies in tropical regions reveal a startling proportion of rickettsial illnesses, especially scrub typhus, murine typhus, and spotted fever group rickettsioses. Laboratory diagnosis of these infections evolved little over the past 40 years, but combinations of technologies like PCR and loop-mediated isothermal amplification, with refined rapid diagnostic tests and/or ELISA, are promising for guidance for early antirickettsial treatment.

RECENT FINDINGS

The long-term reliance on serological tests - useful only late in rickettsial infections - has led to underdiagnosis, inappropriate therapies, and undocumented morbidity and mortality. Recent approaches integrate nucleic acid amplification and recombinant protein-based serological tests for diagnosing scrub typhus. Optimized using Bayesian latent class analyses, this strategy increases diagnostic confidence and enables early accurate diagnosis and treatment - a model to follow for lagging progress in murine typhus and spotted fever.

SUMMARY

A laboratory diagnostic paradigm shift in rickettsial infections is evolving, with replacement of indirect immunofluorescence assay by the more objective ELISA coupled with nucleic acid amplification assays to expand the diagnostic window toward early infection intervals. This approach supports targeted antirickettsial therapy, reduces morbidity and mortality, and provides a robust evidence base for further development of diagnostics and vaccines.

Symptomatic Falciparum Malaria After Living in a Nonendemic Area for 10 Years: Recrudescence or Indigenous Transmission?

AbstractWe report the case of a patient from Mali who, after 10 years of living in Spain, presented with symptomatic Plasmodium falciparum malaria without having visited an endemic area during that time. We cannot completely rule out the possibility of indigenous transmission, but this case most likely represents recrudescence of an infection acquired over 10 years earlier.

Summary of Notifiable Infectious Diseases and Conditions - United States, 2015

The Summary of Notifiable Infectious Diseases and Conditions - United States, 2015 (hereafter referred to as the summary) contains the official statistics, in tabular and graphical form, for the reported occurrence of nationally notifiable infectious diseases and conditions in the United States for 2015. Unless otherwise noted, data are final totals for 2015 reported as of June 30, 2016. These statistics are collected and compiled from reports sent by U.S. state and territories, New York City, and District of Columbia health departments to the National Notifiable Diseases Surveillance System (NNDSS), which is operated by CDC in collaboration with the Council of State and Territorial Epidemiologists (CSTE). This summary is available at https://www.cdc.gov/MMWR/MMWR_nd/index.html. This site also includes summary publications from previous years.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

Role of classic signs as diagnostic predictors for enteric fever among returned travellers: Relative bradycardia and eosinopenia

BACKGROUND

The lack of characteristic clinical findings and accurate diagnostic tools has made the diagnosis of enteric fever difficult. We evaluated the classic signs of relative bradycardia and eosinopenia as diagnostic predictors for enteric fever among travellers who had returned from the tropics or subtropics.

METHODS

This matched case-control study used data from 2006 to 2015 for culture-proven enteric fever patients as cases. Febrile patients (>38.3°C) with non-enteric fever, who had returned from the tropics or subtropics, were matched to the cases in a 1:3 ratio by age (±3 years), sex, and year of diagnosis as controls. Cunha's criteria were used for relative bradycardia. Absolute eosinopenia was defined as an eosinophilic count of 0/μL.

RESULTS

Data from 160 patients (40 cases and 120 controls) were analysed. Cases predominantly returned from South Asia (70% versus 18%, p <0.001). Relative bradycardia (88% versus 51%, p <0.001) and absolute eosinopenia (63% versus 38%, p = 0.008) were more frequent in cases than controls. In multivariate logistic regression analysis, return from South Asia (aOR: 21.6; 95% CI: 7.17-64.9) and relative bradycardia (aOR: 11.7; 95% CI: 3.21-42.5) were independent predictors for a diagnosis of enteric fever. The positive likelihood ratio was 4.00 (95% CI: 2.58-6.20) for return from South Asia, 1.72 (95% CI: 1.39-2.13) for relative bradycardia, and 1.63 (95%CI: 1.17-2.27) for absolute eosinopenia. The negative predictive values of the three variables were notably high (83-92%);. however, positive predictive values were 35-57%.

CONCLUSIONS

The classic signs of relative bradycardia and eosinopenia were not specific for enteric fever; however both met the criteria for being diagnostic predictors for enteric fever. Among febrile returned travellers, relative bradycardia and eosinopenia should be re-evaluated for predicting a diagnosis of enteric fever in non-endemic areas prior to obtaining blood cultures.

A fatal case of melioidosis with pancytopenia in a traveler from Indonesia

Melioidosis, an infectious disease with high mortality, caused by Burkholderia pseudomallei, is endemic in southeast Asia and northern Australia. In Indonesia, autochthonous cases have been rarely reported, with most cases being sporadic and occurring in travelers. Herein, we report a fatal case of neurological melioidosis in a traveler from Indonesia presenting with septic shock.

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.

Interferon-driven alterations of the host's amino acid metabolism in the pathogenesis of typhoid fever

Enteric fever, caused by Salmonella enterica serovar Typhi, is an important public health problem in resource-limited settings and, despite decades of research, human responses to the infection are poorly understood. In 41 healthy adults experimentally infected with wild-type S. Typhi, we detected significant cytokine responses within 12 h of bacterial ingestion. These early responses did not correlate with subsequent clinical disease outcomes and likely indicate initial host-pathogen interactions in the gut mucosa. In participants developing enteric fever after oral infection, marked transcriptional and cytokine responses during acute disease reflected dominant type I/II interferon signatures, which were significantly associated with bacteremia. Using a murine and macrophage infection model, we validated the pivotal role of this response in the expression of proteins of the host tryptophan metabolism during Salmonella infection. Corresponding alterations in tryptophan catabolites with immunomodulatory properties in serum of participants with typhoid fever confirmed the activity of this pathway, and implicate a central role of host tryptophan metabolism in the pathogenesis of typhoid fever.

Case Series of Imported Enteric Fever at a Referral Center in Tokyo, Japan: Antibiotic Susceptibility and Risk Factors for Relapse

Owing to the increase in Salmonella strains with decreased fluoroquinolone susceptibility in the endemic areas, we have been treating enteric fever with intravenous ceftriaxone empirically since 2007. In this study, we reevaluated our treatment protocol. This retrospective cohort study was conducted at a single institute in Tokyo, Japan, between January 2006 and December 2013. Enteric fever was defined as isolation of Salmonella Typhi or Salmonella Paratyphi A, B, and C from the blood and/or stool of patients with fever. Of the 35 patients with imported enteric fever, 28 (80%) had returned from south Asia. Ciprofloxacin-susceptible strains were detected in only 12% of the cases. The isolates showed excellent susceptibility to ampicillin (91%), chloramphenicol (94%), ceftriaxone (97%), and azithromycin (97%). One case of Salmonella Paratyphi B was excluded, and of the remaining 34 patients, 56% were treated with ceftriaxone alone, 26% with ceftriaxone then fluoroquinolone, and 9% with levofloxacin alone. The overall relapse rate was 6.1%; however, among those receiving ceftriaxone monotherapy, the relapse rate was 11% (N = 2). The relapse group was characterized by longer times to treatment initiation (P = 0.035) and defervescence (> 7 days) after treatment initiation (P = 0.022). In such cases, we recommend that ceftriaxone treatment be continued for > 4 days after defervescence or be changed to fluoroquinolone if the strains are found to be susceptible to prevent relapse. Furthermore, ampicillin and chloramphenicol, which are no longer prescribed, may be reconsidered as treatment options in Asia.

Development of Rapid Enzyme-Linked Immunosorbent Assays for Detection of Antibodies to Burkholderia pseudomallei

Burkholderia pseudomallei, the causative agent of melioidosis, is an environmental bacillus found in northeast Thailand. The mortality rate of melioidosis is ∼40%. An indirect hemagglutination assay (IHA) is used as a reference serodiagnostic test; however, it has low specificity in areas where the background seropositivity of healthy people is high. To improve assay specificity and reduce the time for diagnosis, four rapid enzyme-linked immunosorbent assays (ELISAs) were developed using two purified polysaccharide antigens (O-polysaccharide [OPS] and 6-deoxyheptan capsular polysaccharide [CPS]) and two crude antigens (whole-cell [WC] antigen and culture filtrate [CF] antigen) of B. pseudomallei The ELISAs were evaluated using serum samples from 141 culture-confirmed melioidosis patients from Thailand along with 188 healthy donors from Thailand and 90 healthy donors from the United States as controls. The areas under receiver operator characteristic curves (AUROCC) using Thai controls were high for the OPS-ELISA (0.91), CF-ELISA (0.91), and WC-ELISA (0.90), while those of CPS-ELISA (0.84) and IHA (0.72) were lower. AUROCC values using U.S. controls were comparable to those of the Thai controls for all ELISAs except IHA (0.93). Using a cutoff optical density (OD) of 0.87, the OPS-ELISA had a sensitivity of 71.6% and a specificity of 95.7% for Thai controls; for U.S. controls, specificity was 96.7%. An additional 120 serum samples from tuberculosis, scrub typhus, or leptospirosis patients were evaluated in all ELISAs and resulted in comparable or higher specificities than using Thai healthy donors. Our findings suggest that antigen-specific ELISAs, particularly the OPS-ELISA, may be useful for serodiagnosis of melioidosis in areas where it is endemic and nonendemic.

Management of infections in critically ill returning travellers in the intensive care unit-I: considerations on infection control and transmission of resistance

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Person-to-person transmission is the most important means of transmission.

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Malaria remains by far the most important cause of death.

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Surveillance strategies based on epidemiological data (country visited, duration of travel, and time elapsed since return) and clinical syndromes associated with a systematic search policy are usually mandatory to limit the risk of an outbreak.

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Hospitalization in a single-bed room and isolation according to symptoms should be the rule while awaiting laboratory test results.

Depending on their destinations and activities, international travellers are at a significant risk of contracting both communicable and non-communicable diseases. On return to their home countries, such travellers may require intensive care. The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), and more recently Ebola haemorrhagic fever, has highlighted the risks. Other well-known communicable pathogens such as methicillin-resistant Staphylococcus aureus and carbapenemase-producing Enterobacteriaceae have been described previously. However, malaria remains by far the most important cause of death. The issues related to imported antibiotic resistance and protection from highly contagious diseases are reviewed here. Surveillance strategies based on epidemiological data (country visited, duration of travel, and time elapsed since return) and clinical syndromes, together with systematic search policies, are usually mandatory to limit the risk of an outbreak. Single-bed hospital rooms and isolation according to symptoms should be the rule while awaiting laboratory test results. Because person-to-person contact is the main route of transmission, healthcare workers should implement specific prevention strategies.

Severe murine typhus with pulmonary system involvement

We encountered a case of severe murine typhus complicated by acute respiratory distress syndrome. To determine worldwide prevalence of such cases, we reviewed the literature and found that respiratory symptoms occur in ≈30% of murine typhus patients. In disease-endemic areas, murine typhus should be considered for patients with respiratory symptoms and fever.

Illness in the Returned International Traveler

Familiarity with the distribution, mode of transmission, and risk factors for acquisition of illnesses commonly transmitted to travelers to low-income nations can help guide clinicians in their work-up of an ill returned traveler. The 3 most common categories of illness in returned international travelers are gastrointestinal illness, fever, and dermatoses. Diarrhea is the most common illness reported in returned international travelers. Fever is a marker of a potentially significant illness; work-up of the ill febrile returned traveler should be conducted promptly.

Spectrum of Imported Infectious Diseases: A Comparative Prevalence Study of 16,817 German Travelers and 977 Immigrants from the Tropics and Subtropics

The aim of this study was to assess the spectrum of imported infectious diseases (IDs) among patients consulting the University of Munich, Germany, between 1999 and 2014 after being in the sub-/tropics. The analysis investigated complete data sets of 16,817 diseased German travelers (2,318 business travelers, 4,029 all-inclusive travelers, and 10,470 backpackers) returning from Latin America (3,225), Africa (4,865), or Asia (8,727), and 977 diseased immigrants, originating from the same regions (112, 654 and 211 respectively). The most frequent symptoms assessed were diarrhea (38%), fever (29%), and skin disorder (22%). The most frequent IDs detected were intestinal infections with species of Blastocystis(900),Giardia(730),Campylobacter(556),Shigella(209), and Salmonella(183). Also frequently observed were cutaneous larva migrans (379), dengue (257), and malaria (160). The number of IDs with significantly elevated proportions was higher among backpackers (18) and immigrants (17), especially among those from Africa (18) and Asia (17), whereas it was lower for business travelers (5), all-inclusive travelers (1), and those from Latin America (5). This study demonstrates a large spectrum of imported IDs among returning German travelers and immigrants, which varies greatly based not only on travel destination and origin of immigrants, but also on type of travel.

Pre-travel advice concerning vector-borne diseases received by travelers prior to visiting Cuzco, Peru

Peru is an increasingly popular tourist destination that poses a risk to travelers due to endemic vector-borne diseases (VBDs). The objective of our study was to determine which factors are associated with receiving pre-travel advice (PTA) for VBDs among travelers visiting Cuzco, Peru. A cross-sectional secondary analysis based on data from a survey among travelers departing Cuzco at Alejandro Velazco Astete International Airport during the period January-March 2012 was conducted. From the 1819 travelers included in the original study, 1717 were included in secondary data analysis. Of these participants, 42.2% received PTA and 2.9% were informed about vector-borne diseases, including yellow fever (1.8%), malaria (1.6%) and dengue fever (0.1%). Receiving information on VBDs was associated with visiting areas endemic to yellow fever and dengue fever in Peru. The only disease travelers received specific recommendations for before visiting an endemic area for was yellow fever. Only 1 in 30 tourists received information on VBD prevention; few of those who traveled to an endemic area were warned about specific risks for infectious diseases prior to their trip. These important findings show that most tourists who travel to Peru do not receive PTA for the prevention of infectious and VBD, which can affect not only the travelers but their countries of origin as well.

Diagnosing dengue virus infection: rapid tests and the role of micro/nanotechnologies

Due to the progressive spread of the dengue virus and a rising incidence of dengue disease, its rapid diagnosis is important for developing countries and of increasing relevance for countries in temperate climates. Recent advances in bioelectronics, micro- and nanofabrication technologies have led to new miniaturized point-of-care devices and analytical platforms suited for rapid detection of infections. Starting from the available tests for dengue diagnosis, this review examines emerging rapid, micro/nanotechnologies-based tools, including label-free biosensor methods, microarray and microfluidic platforms, which hold significant potential, but still need further development and evaluation. The epidemiological and clinical setting as key determinants for selecting the best analytical strategy in patients presenting with fever is then discussed. This review is aimed at the clinicians and microbiologists to deepen understanding and enhance application of dengue diagnostics, and also serves as knowledge base for researchers and test developers to overcome the challenges posed by this disease.

FROM THE CLINICAL EDITOR

Dengue disease remains a significant problem in many developing countries. Unfortunately rapid diagnosis with easy and low cost tests for this disease is currently still not realized. In this comprehensive review, the authors highlighted recent advances in nanotechnology which would enable development in this field, which would result in beneficial outcomes to the population.

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.

Massive intra-alveolar hemorrhage caused by Leptospira serovar Djasiman in a traveler returning from Laos

Leptospirosis is one of the most common pathogens responsible for life-threatening tropical disease in travelers. We report a case of massive intra-alveolar hemorrhage caused by Leptospira serovar Djasiman in a 38-year-old man returning from Laos, who was cured with antibiotics and salvage treatment with extra-corporeal membrane oxygenation.

Leptospirosis presenting as honeymoon fever

An increasing number of travelers from western countries visit tropical regions, questioning western physicians on the prophylaxis, the diagnosis and the therapeutic management of patients with travel-associated infection. In July 2014, a French couple stayed for an adventure-travel in Columbia without malaria prophylaxis. A week after their return the woman presented with fever, myalgia, and retro-orbital pain. Three days later, her husband presented similar symptoms. In both patients, testing for malaria, arboviruses and blood cultures remained negative. An empirical treatment with doxycycline and ceftriaxone was initiated for both patients. Serum collected from the female patient yielded positive IgM for leptospirosis but was negative for her husband. Positive Real-Time PCR were observed in blood and urine from both patients, confirming leptospirosis. Three lessons are noteworthy from this case report. First, after exclusion of malaria, as enteric fever, leptospirosis and rickettsial infection are the most prevalent travel-associated infections, empirical treatment with doxycycline and third generation cephalosporin should be considered. In addition, the diagnosis of leptospirosis requires both serology and PCR performed in both urine and blood samples. Finally, prophylaxis using doxycycline, also effective against leptospirosis, rickettsial infections or travellers' diarrhea should be recommended for adventure travelers in malaria endemic areas.

Dengue

Dengue viruses have spread rapidly within countries and across regions in the past few decades, resulting in an increased frequency of epidemics and severe dengue disease, hyperendemicity of multiple dengue virus serotypes in many tropical countries, and autochthonous transmission in Europe and the USA. Today, dengue is regarded as the most prevalent and rapidly spreading mosquito-borne viral disease of human beings. Importantly, the past decade has also seen an upsurge in research on dengue virology, pathogenesis, and immunology and in development of antivirals, vaccines, and new vector-control strategies that can positively impact dengue control and prevention.

Vaccine-preventable travel health risks: what is the evidence--what are the gaps?

BACKGROUND

Existing travel health guidelines are based on a variety of data with underpinning evidence ranging from high-quality randomized controlled trials to best estimates from expert opinion. For strategic guidance and to set overall priorities, data about average risk are useful. The World Health Organization (WHO) plans to base future editions of "International Travel and Health" on its new "Handbook for Guideline Development."

METHODS

Based on a systematic search in PubMed, the existing evidence and quality of data on vaccine-preventable disease (VPD) risks in travelers was examined and essentials of vaccine efficacy were briefly reviewed. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework was used to evaluate the quality of the data.

RESULTS

Moderate-quality data to determine the risk of VPD exist on those that are frequently imported, whereas in most others the level of confidence with existing data is low or very low.

CONCLUSIONS

In order for the WHO to produce graded risk statements in the updated version of "International Travel and Health," major investment of time plus additional high-quality, generalizable risk data are needed.

Advice on malaria and yellow fever prevention provided at travel agencies in Cuzco, Peru

BACKGROUND

Travelers receive medical advice from a variety of sources, including travel agencies. The aim of this study is to describe the quality of pre-travel advice provided by travel agencies in Cuzco to travelers interested in visiting malaria and yellow fever endemic areas.

METHODS

Trained medical students posed as tourists and visited travel agencies in Cuzco requesting travel advice for a trip to the southern Amazon of Peru, recording advice regarding risk and prevention of malaria and yellow fever.

RESULTS

A total of 163 registered travel agencies were included in the study. The mean proposed tour duration was 6.8 days (±1.4 days) with a median time to departure of 3 days and a median tour cost of 805 US dollars (USD) [interquartile range (IQR) 580-1,095]. Overall, 45% employees failed to mention the risk for any illness. Eighteen percent of the employees acknowledged risk of malaria and 53% risk of yellow fever. However, 36% denied malaria risk and 2% denied risk of yellow fever in the region. The price of tours from travel agencies that did not mention any health risk was significantly lower [1,009.6 ± 500.5 vs 783.9 ± 402 USD, t (152) = 3, p < 0.01] compared with the price from agencies that did mention health risks. Almost all who acknowledged malaria (97%) and/or yellow fever (100%) were able to provide at least one recommendation for prevention. However, advice was not always accurate or spontaneously volunteered. Only 7% of the employees provided both correct scheduling and location information for administration of the yellow fever vaccine.

CONCLUSIONS

The majority of registered travel agencies in Cuzco did not provide sufficient and accurate information regarding risk and prevention of malaria and yellow fever to travelers inquiring about trips to the southern Amazon of Peru.

Failure of atovaquone-proguanil malaria chemoprophylaxis in a traveler to Ghana

Clinical failure of Malarone™ chemoprophylaxis is extremely rare. We report a case of Plasmodium falciparum malaria in a returned traveler to Ghana who fully adhered to atovaquone-proguanil (Malarone™) chemoprophylaxis daily dosing, yet took the pills on an empty stomach. Screening of the P. falciparum isolate revealed triple codon mutation of Dhfr at positions 51, 59, and 108. Plasma drug levels of both atovaquone and proguanil revealed sub-therapeutic concentrations.

Leptospirosis in Sub-Saharan Africa: a systematic review

BACKGROUND

Leptospirosis is an emerging zoonotic infection worldwide, possibly due to climate change and demographic shifts. It is regarded as endemic in Sub-Saharan Africa; however, for most countries scarce epidemiological data, if any, exist. The primary objectives were to describe the prevalence of leptospirosis in countries in Sub-Saharan Africa, and to develop options for prevention and control in the future.

METHODS

A systematic review was conducted to determine the prevalence of leptospirosis in Sub-Saharan Africa; the PRISMA guidelines were followed. Medline/PubMed, Embase, The Cochrane Library, Web of Science, BIOSIS Previews, the African Index Medicus, AJOL, and Google Scholar were searched.

RESULTS

Information about the prevalence and incidence of leptospirosis in humans is available, but remains scarce for many countries. Data are unavailable or outdated for many countries, particularly those in Central Africa. Most data are available from animals, probably due to the economic losses caused by leptospirosis in livestock. In humans, leptospirosis is an important cause of febrile illness in Sub-Saharan Africa. It concerns numerous serogroups, harboured by many different animal carriers.

DISCUSSION

A wide variety of data was identified. Prevalence rates vary throughout the continent and more research, especially in humans, is needed to reliably gauge the extent of the problem. Preventive measures need to be reconsidered to control outbreaks in the future.

Globalization of leptospirosis through travel and migration

Leptospirosis remains the most widespread zoonotic disease in the world, commonly found in tropical or temperate climates. While previous studies have offered insight into intra-national and intra-regional transmission, few have analyzed transmission across international borders. Our review aimed at examining the impact of human travel and migration on the re-emergence of Leptospirosis. Results suggest that alongside regional environmental and occupational exposure, international travel now constitute a major independent risk factor for disease acquisition. Contribution of travel associated leptospirosis to total caseload is as high as 41.7% in some countries. In countries where longitudinal data is available, a clear increase of proportion of travel-associated leptospirosis over the time is noted. Reporting patterns is clearly showing a gross underestimation of this disease due to lack of diagnostic facilities. The rise in global travel and eco-tourism has led to dramatic changes in the epidemiology of Leptospirosis. We explore the obstacles to prevention, screening and diagnosis of Leptopirosis in health systems of endemic countries and of the returning migrant or traveler. We highlight the need for developing guidelines and preventive strategies of Leptospirosis related to travel and migration, including enhancing awareness of the disease among health professionals in high-income countries.

Rickettsial infections in Southeast Asia: implications for local populace and febrile returned travelers

Rickettsial infections represent a major cause of non-malarial febrile illnesses among the residents of Southeast Asia and returned travelers from that region. There are several challenges in recognition, diagnosis, and management of rickettsioses endemic to Southeast Asia. This review focuses on the prevalent rickettsial infections, namely, murine typhus (Rickettsia typhi), scrub typhus (Orientia tsutsugamushi), and members of spotted fever group rickettsiae. Information on epidemiology and regional variance in the prevalence of rickettsial infections is analyzed. Clinical characteristics of main groups of rickettsioses, unusual presentations, and common pitfalls in diagnosis are further discussed. In particular, relevant epidemiologic and clinical aspects on emerging spotted fever group rickettsiae in the region, such as Rickettsia honei, R. felis, R. japonica, and R. helvetica, are presented. Furthermore, challenges in laboratory diagnosis and management aspects of rickettsial infections unique to Southeast Asia are discussed, and data on emerging resistance to antimicrobial drugs and treatment/prevention options are also reviewed.