Comparison of clinical and laboratory parameters of primary vs secondary dengue fever in travellers

BACKGROUND

Dengue fever (DF), caused by the dengue virus (DENV), is the most common arboviral disease in travellers worldwide. It is hypothesized that compared with primary DF, secondary DF may result in antibody-dependent enhancement of the immune response, resulting in more severe disease. We aimed to compare clinical and laboratory parameters in travellers with primary and secondary DF to determine whether secondary DF is associated with markers of severe disease.

METHODS

We conducted a retrospective cohort study, which included all patients diagnosed with DF at the Central Virology Laboratory of the Israeli Ministry of Health during 2008-19. Clinical, laboratory and virological data were extracted from laboratory and patient records. A diagnosis of DENV infection was based on a positive nonstructural protein 1 (NS1) test, polymerase chain reaction or serology testing for immunoglobulin M (IgM) and immunoglobulin G (IgG). Primary and secondary infections were classified based on travel history, NS1 result and IgM/IgG ratio. Severe DF was defined according to WHO classification.

RESULTS

We identified 245 DF cases: 210 (86%) primary and 35 (14%) secondary. Whilst fever duration was significantly longer in secondary compared with primary infections (6.4 vs 5.3 days, P = 0.027), mean Aspartate aminotransferase levels were significantly higher in primary compared with secondary cases (146 vs 65 U/L, P < 0.001), and no other clinical or laboratory parameter differed significantly between the groups. Of note, only four patients had severe DF, all had primary infections and none died.

CONCLUSIONS

In a cohort of returning travellers with DF, secondary infection, compared with primary infection, was not associated with a consistent trend towards greater severity of the clinical and laboratory markers examined in this study.

Association between thrombin generation and clinical characteristics in COVID-19 patients

Introduction: COVID-19 disease is associated with coagulopathy and increased risk of thrombosis. An association between thrombin generation (TG) capacity, disease severity and outcomes has not been well described. Methods: We assessed the correlation of TG with sequential organ failure assessment (SOFA) and sepsis-induced coagulopathy (SIC) scores and clinical outcomes by analysis of plasma samples obtained from hospitalized COVID-19 patients. Results: 32 patients (68.8% male), whose median age was 69 years were assessed, of whom only 3 patients did not receive anticoagulant therapy. D-dimers were uniformly increased. During hospitalization 2 patients suffered thrombosis, 3 experienced bleeding and 12 died. TG parameters from anticoagulated COVID-19 patients did not significantly differ from the values obtained from non-anticoagulated healthy controls. Patients who received higher than prophylactic doses of anticoagulant therapy had increased lag time (P = 0.003), lower endogenous thrombin potential (ETP) (P = 0.037), and a reduced peak height (P = 0.006). ETP correlated with the SIC score (P = 0.038). None of the TG parameters correlated with the SOFA score or were associated with mortality. Conclusion: TG was not associated with disease severity among patients hospitalized with COVID-19. However, a correlation between ETP and the SIC score was noted and deserves attention.

Incidence of dengue fever in Israeli travelers 2008-2019

BACKGROUND

. Dengue virus (DENV) is a frequent travel-related infection, but longitudinal data on its incidence is limited. We aimed to study temporal trends of travel-related DENV burden and its geographical sources.

METHODS

. All cases of laboratory-confirmed DENV infection diagnosed at the Central Virology Laboratory of the Israeli Ministry of Health during 2008-2019 were evaluated. Numbers of Israeli tourist-entries to DENV endemic countries were available from the UN World Tourist Organization (UNWTO) database. DENV attack rates were calculated as cases per 100,000 traveler-entries. In addition, for Thailand and India incidence rates were calculated, using the average duration of stay reported in diagnosed DENV cases.

RESULTS

. During 2008-2019, 425 Israeli travelers were diagnosed with DENV: 80.3%, 12.8% and 6.9% were acquired in Asia, America and Africa respectively. The average global DENV attack rate increased from 2.5 cases per 100,000 tourist-entries in 2008 to 10.7 cases per 100,000 tourist-entries in 2019. Region-specific DENV attack rates were 4.4, 3.2 and 2.1 cases per 100,000 tourist-entries to Asia, Africa, and America respectively. The highest number of DENV cases were reported from Thailand and India; DENV incidence rates increased from 94.5 to 142.2 cases per 100,000 travel-years, and from 49.3 to 90.4 cases per 100,000 travel-years for Thailand and India respectively.

CONCLUSION

. Among Israeli travelers, worldwide DENV attack-rates have quadrupled during 2008-2019, reflecting both a growing DENV burden in Asia, but also the emergence of Africa as an important source of DENV. The need to protect travelers through vaccination remains urgent.

Schistosomiasis: still a neglected disease

Schistosomiasis remains an infrequent travel-related disease, mostly affecting returnees from Sub-Saharan Africa. The neglect of schistosomiasis research and development has consequences not only for endemic populations but also for travellers. Recent studies highlight deficits in clinical recognition, diagnostics and therapy of travel-related schistosomiasis, with significant morbidity, both acute and chronic.

Rabies Vaccine Disposition: Trends in Vaccination Among Israeli Travelers

Travelers are a risk-group for rabies; however, few are protected. We describe changes in pre-travel vaccination rates and post-travel referrals after animal contact. We conducted a nationwide, retrospective study for 2014-2018. The ratio of rabies vaccine courses distributed to travelers and the number of Israeli-tourist-entries to endemic countries was calculated, as was the proportion of travelers referred to a post-travel clinic after animal contact. During the study period, the ratio of pre-travel vaccine courses distributed nationally to outgoing tourism to endemic countries was stable at ≈0.7%; 13% of 256,969 pre-travel consultations included recommendation for rabies vaccination. Backpackers were more likely to be immunized (40.2%) than business travelers (4.4%) or travelers planning organized/high-end travel (2.0%). However, rates of rabies vaccination among backpackers showed a decline during the study period. Post-travel referrals after animal contact were stable at 2% of all referrals; most were exposed in Asia (69.5%) and 51% were bitten by dogs. Only 38% received post-exposure prophylaxis abroad. We conclude that only a minority of Israeli travelers, including backpackers, receive rabies pre-exposure prophylaxis. The proportion of travelers with potentially rabid animal contact is not decreasing; however, many exposed travelers do not receive post-exposure prophylaxis during travel. Because rabies control programs have been compromised in endemic countries during the COVID-19 pandemic, the need to provide rabies protection to travelers has become more urgent. After the ACIP's adoption of the World Health Organization's (WHO) 2-dose regimen, a revision of current vaccine guidelines is required to provide a simplified, more inclusive rabies vaccine policy.

Typhoid and paratyphoid fever: a clinical seminar

Rationale for review: Enteric fever (EF) caused by Salmonella enterica subspecies enterica serovar Typhi (Salmonella Typhi) and S. Paratyphi (Salmonella Paratyphi) remains an important cause of infectious morbidity and mortality in many low-income countries and, therefore, still poses a major infectious risk for travellers to endemic countries. Main findings: Although the global burden of EF has decreased over the past two decades, prevalence of EF remains high in Asia and Africa, with the highest prevalence reported from the Indian subcontinent. These statistics are mirrored by data on travel-related EF. Widespread and increasing antimicrobial resistance has narrowed treatment options for travel-related EF. Ceftriaxone- and azithromycin-based therapies are commonly used, even with the emergence of extremely drug-resistant typhoid in Pakistan. Preventive measures among locals and travellers include provision of safe food and water and vaccination. Food and water precautions offer limited protection, and the efficacy of Salmonella Typhi vaccines is only moderate signifying the need for travellers to be extra cautious. Recommendations: Improvement in the diagnosis of typhoid with high degree of clinical suspicion, better diagnostic assays, early and accurate detection of resistance, therapy with appropriate drugs, improvements in hygiene and sanitation with provision of safe drinking water in endemic areas and vaccination among travellers as well as in the endemic population are keys to controlling typhoid. While typhoid vaccines are recommended for travellers to high-risk areas, moderate efficacy and inability to protect against Salmonella Paratyphi are limitations to bear in mind. Improved Salmonella Typhi vaccines and vaccines against Salmonella Paratyphi A are required.

Utility of 8-Aminoquinolines in Malaria Prophylaxis in Travelers

PURPOSE OF REVIEW

To review the current status of 8-aminoquinolines in the prophylaxis of malaria among travelers, in light of the recent approval of tafenoquine.

RECENT FINDINGS

Primaquine continues to provide excellent primary prophylaxis against all Plasmodium species. Tafenoquine provides similarly good prophylaxis, with the benefit of weekly dosing. Both agents require glucose-6-phosphate dehydrogenase activity testing before use and are contraindicated in pregnancy. Pharmacodynamic variability relating to CYP2D6 may underlie some cases of primaquine failure; the effects of CYP2D6 on tafenoquine efficacy require further study. Tafenoquine and primaquine are the only current drugs that provide complete malaria prophylaxis, and should be considered the agents of choice in areas where both P. vivax and falciparum are frequent. Monthly tafenoquine is promising and should be further studied in travelers.

Vivax Malaria Chemoprophylaxis: The Role of Atovaquone-Proguanil Compared to Other Options

Background

Atovaquone-proguanil is considered causal prophylaxis (inhibition of liver-stage schizonts) for Plasmodium falciparum; however, its causal prophylactic efficacy for Plasmodium vivax is not known. Travelers returning to nonendemic areas provide a unique opportunity to study P. vivax prophylaxis.

Methods

In a retrospective observational study, for 11 years, Israeli rafters who had traveled to the Omo River in Ethiopia, a highly malaria-endemic area, were followed for at least 1 year after their return. Malaria prophylaxis used during this period included mefloquine, doxycycline, primaquine, and atovaquone-proguanil. Prophylaxis failure was divided into early (within a month of exposure) and late malaria.

Results

Two hundred fifty-two travelers were included in the study. Sixty-two (24.6%) travelers developed malaria, 56 (91.9%) caused by P. vivax, with 54 (87.1%) cases considered as late malaria. Among travelers using atovaquone-proguanil, there were no cases of early P. falciparum or P. vivax malaria. However, 50.0% of atovaquone-proguanil users developed late vivax malaria, as did 46.5% and 43.5% of mefloquine and doxycycline users, respectively; only 2 (1.4%) primaquine users developed late malaria (P < .0001).

Conclusions

Short-course atovaquone-proguanil appears to provide causal (liver schizont stage) prophylaxis for P. vivax, but is ineffective against late, hypnozoite reactivation-related attacks. These findings suggest that primaquine should be considered as the chemoprophylactic agent of choice for areas with high co-circulation of P. falciparum and P. vivax.

Zika Virus in Israeli Travelers: Emergence of Asia as a Major Source of Infection

Zika virus (ZIKV) had emerged as a global arboviral concern since late 2015. In this study, we describe the results of ZIKV testing in returning Israeli travelers from Zika-endemic countries. We conducted a nation-wide prospective observational study, including all ZIKV tests during January 2016-June 2017. Zika virus infection was defined as confirmed, if diagnosed by polymerase chain reaction (PCR) or serology confirmed by neutralization, and as possible if diagnosed by serology alone. During the study period, 1,188 travelers were tested: 66.7%, 30.5%, 1.6%, and 1.2% had returned from the Americas, Asia, Africa, and Oceania, respectively. Thirty persons were diagnosed with ZIKV. Most travelers tested were women of reproductive age; the gender ratio among infected travelers however was 1.0. During 2016, 19/20 (95%) ZIKV cases were acquired in the Americas; in 2017, however, 6/10 (60%) cases were acquired in Asia. Of 248 symptomatic travelers, 28 (11.3%) were diagnosed with ZIKV infection, whereas only 2/940 (0.2%) of asymptomatic travelers were diagnosed with ZIKV infection Odds ratio = 59.7 (95% confidence interval: 14.1-252.5, P < 0.0001). Our findings suggest that although women are more likely to be referred for ZIKV testing, gender does not affect the likelihood of ZIKV infection and that asymptomatic ZIKV infection appears to be rare in travelers. Furthermore, it appears that in 2017, Southeast Asia emerges as the leading source of travel-related ZIKV infection.

Acute Diarrhea in North American Students after Relocation to Israel: A Pilot Study

BACKGROUND

Travelers' diarrhea (TD) is frequently encountered in people traveling from high-income to low-income countries; however, its epidemiology in those traveling between high-income countries is not known.

OBJECTIVES

To evaluate the incidence of diarrhea in North American students relocating to Israel.

METHODS

A retrospective cohort study involving medical students from the United States and Canada relocating to Israel was conducted. Students who relocated to Israel during 2010-2016 were contacted by email to participate in an anonymous survey. Data included demographic information as well as occurrence, timing, duration, and outcome of diarrhea after relocation.

RESULTS

Ninety-seven students participated in the survey. Most (93.7%) students relocated from the United States or Canada. The period-prevalence of diarrhea was 69.1%. The incidence of diarrhea declined from 34.8 cases per 100 student-months during the first month after relocation to 1.3 cases per 100 student-months after 1 year. The duration of diarrhea was up to 1 week in 72.7%. Students who reported diarrhea were younger than students who did not (mean age 24.0 ± 2.2 and 28.4 ± 1.8 years, respectively, P < 0.001). No other demographic parameter was significantly associated with a higher likelihood of diarrhea.

CONCLUSIONS

A high proportion of North American medical students relocating to Israel reported diarrhea with clinical and epidemiological features similar to classic TD. Further studies are needed to elucidate the causative agents of TD in Israel.

[TRAVEL MEDICINE IN ISRAEL: ITS HISTORY AND CONTRIBUTIONS TO THE DISCIPLINE]

The last century in Israel had seen a profound change in the field of travel-related infectious diseases. During the 19th century and throughout the first half of the 20th century, most scientific observations related to the various endemic infections in Palestine, and the risk they posed to the passengers/immigrants. Among the infectious hazards that have characterized the country, malaria, typhoid, cutaneous leishmaniasis, and bilharzia were especially noteworthy. With the establishment of the State of Israel and following the great waves of immigration to Israel, many endemic diseases declined or were completely eradicated, such as malaria. Since the 1980's, the emergence of the Israeli backpacking phenomenon was accompanied by a surge of imported infectious diseases, from Latin America, the Far East and Africa. Israeli travel medicine has documented these developments, with an important contribution to the literature on epidemiology, clinical aspects and the treatment and prevention of many travel-related infections.

Region-Specific, Life-Threatening Diseases among International Travelers from Israel, 2004-2015

We characterized posttravel hospitalizations of citizens returning to Israel by summarizing the returning traveler hospitalization dataset of the national referral Center for Travel Medicine and Tropical Diseases at Sheba Medical Center in Israel. Of 722 hospitalizations, 181 (25%) infections were life-threatening; most would have been preventable by chemoprophylaxis and pretravel vaccination.

D-dimer levels in non-immune travelers with malaria

BACKGROUND

Elevated serum D-dimer levels may reflect endothelial activation, which in malaria may correlate with parasite biomass and disease severity.

METHODS

We performed a retrospective chart review of all non-immune travelers hospitalized with malaria during 01/2000-12/2014 at the Sheba Medical Center, Israel. Admission and peak D-dimer levels were compared among malaria patients, according to Plasmodium species and severity.

RESULTS

Complete laboratory data was available for 94/168 travelers hospitalized with malaria, with 68.1% caused by P. falciparum. Admission D-dimer levels were significantly higher in P. falciparum malaria compared to non-falciparum malaria cases (3585 ± 7045 and 802 ± 1248 ng/dL respectively, p = 0.04). Admission D-dimer levels were higher in patients with severe compared to non-severe P. falciparum malaria (4058 ± 3544 & 3490 ± 7549 ng/dL), however the difference was short of statistical significance (P = 0.06). Peak D-dimer levels were also significantly higher in severe and non-severe P. falciparum than in non-falciparum cases.

CONCLUSIONS

In most non-immune travelers with malaria, D-dimer levels are elevated, are higher in P. falciparum malaria compared to non-falciparum malaria, and appear to increase with disease severity, probably reflecting the level of endothelial damage.

Travel-Related Tick-Borne Encephalitis, Israel, 2006-2014

During 2006–2014, four tick-borne encephalitis (TBE) cases occurred among Israeli travelers. We calculated TBE incidence at 321.0, 45.0, 13.2, and 7.5 cases/100,000 travelers/year of travel to Sweden, Switzerland, Austria, and Germany, respectively. TBE incidence among travelers to these destinations appears to justify TBE vaccination in accordance with World Health Organization recommendations.

The Clinical Spectrum of Zika Virus in Returning Travelers

INTRODUCTION

The clinical spectrum of Zika virus had, to date, been described in small series from endemic/epidemic countries and is not well established.

METHODS

We describe the clinical manifestations of laboratory-proven Zika virus infection in Israeli travelers during December 2015-February 2016, and review all published cases of travel-related Zika virus.

RESULTS

During the study period, 8 returning Israeli travelers were diagnosed with Zika virus infection. In addition, 41 published cases were included, mostly from Latin America to Europe and North America. Overall, 65.3% were diagnosed by polymerase chain reaction. Rash was the most frequent symptom, present in 95.7% of cases, followed by fever and arthralgia. Conjunctivitis was present in 53.1%; however, only 40.3% presented with a triad of conjunctivitis, fever, and rash. Less frequent symptoms included dysgeusia and nightmares, which, together with arthralgia, persisted for several weeks in some travelers.

CONCLUSIONS

Zika virus clinical picture in travelers is diverse. Prolonged symptoms may occur.

Treatment of giardiasis after nonresponse to nitroimidazole

During January 2008–October 2013, a total of 12 cases of giardiasis at the Chaim Sheba and Shaare Zedek Medical Centers, Israel, did not respond to nitroimidazole; 83.3% were associated with travel and 33% with immunoglobulin deficiency. Among 110 published cases, the most effective treatment was quinacrine (efficacy 90%–100%), but its availability is limited.

Primaquine dosing errors: the human cost of a pharmaceutical anachronism

Confusion between salt/base forms of primaquine may result in malaria prophylaxis failure. During 1995-2011, there were 14 malaria cases in Israel despite primaquine primary prophylaxis. In 6/14 cases, primaquine was underdosed because of confusion between salt and base forms, including two Plasmodium falciparum cases. Primaquine labeling clarification may be lifesaving.

Artemether-lumefantrine compared to atovaquone-proguanil as a treatment for uncomplicated Plasmodium falciparum malaria in travelers

Atovaquone-proguanil (AP) and artemether-lumefantrine (AL) are both treatments for uncomplicated Plasmodium falciparum malaria, but comparative clinical trials are lacking. We performed a retrospective analysis, comparing treatment failure and fever clearance time in non-immune travelers with uncomplicated P. falciparum malaria, treated with AP or AL. Sixty-nine patients were included during 2001-2013: 44 in the AP group and 25 in the AL group. Treatment failure was observed in 6 of 44 (13.6%) and 1 of 25 (4.0%) patients in the AP and AL groups, respectively. Six treatment failures were observed in travelers from West Africa. Fever clearance time was 44 ± 23 h in AL group versus 77 ± 28 h in AP group, (P < 0.001). Hospitalization time was significantly shorter in the AL group; 3.8 + 1.3 versus 5.1 + 2.8 days in the AP group (P = 0.04) In conclusion, travelers with uncomplicated P. falciparum malaria recover faster on AL than on AP. The AL should probably be the drug of choice for this population.

Potential drug interactions in travelers with chronic illnesses: a large retrospective cohort study

BACKGROUND

Data regarding the prevalence of potential interactions between travel-related medications (TRM) and chronic medications in use, or medical conditions of travelers to developing countries are limited.

METHODS

A retrospective cohort study of travelers to low income countries. We extracted data on demographics, travel destinations, use of chronic medications, drug allergies, and relevant medical conditions. The following TRM were evaluated: mefloquine, primaquine, doxycycline, atovaquone/proguanil, fluoroquinolone antibiotics, rifaximin, azithromycin, and acetazolamide.

RESULTS

A total of 16,263 travelers were included in the analysis, of whom 3299(20%) suffered from chronic illnesses and 2316(14%) reported chronic medication use. A potential drug-drug interaction with TRM was identified in 1047(45%) of travelers using chronic medication. Fluoroquinolones and azithromycin were the most commonly implicated TRMs. A potential medical condition interaction with TRM was identified in 717(22%) of travelers having chronic illnesses. acetazolamide, primaquine and mefloquine, were the most commonly TRMs implicated. Drug allergies, which can pose a relative contraindication for use of acetazolamide, were reported by 1323(8.1%) of all travelers.

CONCLUSIONS

Potential drug-drug and drug-disease interactions involving TRM might occur in a significant proportion of travelers with chronic medical conditions. Education of health practitioners regarding such potential drug interactions and caution when in prescribing travel-related medications is warranted.

Effectiveness of short prophylactic course of atovaquone-proguanil in travelers to sub-saharan Africa

BACKGROUND

Current guidelines recommend continuation of atovaquone-proguanil (AP) malaria prophylaxis for 7 days after leaving Plasmodium falciparum endemic areas. Evidence from clinical studies suggests that discontinuation of AP 1 day after exposure ends may be safe and effective. Our objective was to assess the effectiveness of short-course AP prophylaxis among travelers to sub-Saharan Africa.

METHODS

To detect prophylactic failures associated with short-course AP prophylaxis discontinued 1 day after return, we conducted active surveillance during the years 2010 and 2011, by a retrospective telephone survey 1 to 6 months after travelers' return. Passive surveillance data were obtained from the Israel Ministry of Health (MOH) malaria registry.

RESULTS

Among 485 travelers to sub-Saharan Africa (cumulative exposure of 4,979 days), 421 (87%) discontinued AP 1 day after leaving the endemic region (cumulative exposure of 4,337 days). None of the 485 travelers reported malaria infection. The MOH malaria registry survey included 363 P. falciparum-infected patients during the years 2003 to 2011. The majority (n = 305; 84%) did not use any malaria prophylaxis. None of the patients had used AP (neither regular nor short course AP) for malaria prophylaxis.

CONCLUSIONS

We did not detect prophylaxis failures among a group of travelers who discontinued AP prophylaxis 1 day after leaving malaria-endemic areas. Passive surveillance in Israel did not detect any P. falciparum cases among AP users. We recommend further validation of our findings by clinical trials, prospective studies, and active surveillance in larger cohorts to assess the effectiveness of short-course AP prophylaxis in travelers.

The changing epidemiology of human African trypanosomiasis among patients from nonendemic countries--1902-2012

BACKGROUND

Although human African trypanosomiasis (HAT) is uncommon among patients from non-endemic countries (NEC), there has been an increase in the number of cases reported in recent years.

METHODS

A systematic review of the literature was performed. The number of incoming tourists to HAT endemic countries was obtained from the United Nations World Tourism Organization. All HAT cases diagnosed in patients from NEC were included. Immigrants and refugees were excluded. We compared patients during and after the colonial period, and analyzed the relationship between the number of incoming travellers and the number of HAT cases.

RESULTS

Between 1902 and 2012, HAT was reported in 244 patients. Most HAT cases were reported before 1920, and after the year 2000. In the colonial era the average age of patients was lower (32.5±7.8 vs. 43.0±16.1 years, P<0.001), the proportion of females was lower (10.0% vs. 23.9%, P<0.01], most cases were diagnosed in expatriates, missionaries and soldiers (74.3%), and Gambian trypanosomiasis accounted for 86/110, (78%) of cases. In the post-colonial era most patients 91/125 (72.8%) were short-term tourists to game parks in Eastern and South-Eastern Africa (mainly in Tanzania); Rhodesian trypanosomiasis accounted for 94/123 (76.4%) of cases. Between 1995 and 2010 there has been a constant linear increase in the number of incoming tourists to Tanzania, and HAT cases occurred in small outbreaks rather than following a similar linear pattern.

CONCLUSIONS

In recent decades HAT patients from NEC are older, and more likely to be tourists who acquired the disease while visiting game-parks in Eastern and South-Eastern Africa. While Rhodesian trypanosomiasis is relatively uncommon among Africans, it now accounts for most cases reported among patients from NEC. Returning febrile travellers without an alternative diagnosis should be evaluated for HAT. Cases among travellers may serve as sentinels for Rhodesian trypanosomiasis "hot spots" in Africa.

Exploring the origin and potential for spread of the 2013 dengue outbreak in Luanda, Angola

INTRODUCTION

Dengue in Africa is underreported. Simultaneous reports of travellers with dengue returning from Luanda, Angola, to six countries on four continents suggest that a major dengue outbreak is currently occurring in Angola, South West Africa.

METHODS

To identify the origin of the imported dengue virus, we sequenced the virus from Angola and investigated the interconnectivity via air travel between dengue-endemic countries and Angola.

RESULTS AND CONCLUSION

Our analyses show that the Angola outbreak was most likely caused by an endemic virus strain that had been circulating in West Africa for many years. We also show that Portugal and South Africa are most likely at the highest risk of importation of dengue from Angola due to the large number of air passengers between Angola and these countries.

Detection on four continents of dengue fever cases related to an ongoing outbreak in Luanda, Angola, March to May 2013

In April 2013, ten cases of dengue fever in travellers returning from Luanda, Angola, to five countries on four continents, were reported to the globally distributed GeoSentinel Surveillance network. Dengue virus serotype 1 was identified in two cases. The findings indicate that a major dengue outbreak is currently ongoing in Luanda. This report illustrates how cases from an emerging arboviral epidemic focus can spread internationally and highlights the risk of dissemination of a vector-borne disease into receptive areas

Human African trypanosomiasis in a traveler: diagnostic pitfalls

Abstract. An Israeli traveler returning from Tanzania presented with a relapsing febrile illness. A diagnosis of Trypanosoma brucei rhodesiense infection was established by blood smear after nearly a month. Blood polymerase chain reaction failed to provide an early diagnosis of human African trypanososmiasis. Recognition of suggestive signs should prompt physicians to perform repeated tests before ruling out human African trypanososmiasis.

Capillary leakage in travelers with dengue infection: implications for pathogenesis

Dengue hemorrhagic fever is characterized by the presence of a capillary leak syndrome. Its pathogenesis is presumed to differ from that of classical dengue fever (DF) and to be associated with secondary dengue infection. Returning travelers given a diagnosis of DF were evaluated for capillary leakage with abdominal sonography. Data were compared between travelers with primary/secondary infection defined by epidemiologic and serologic parameters. A total of 12 (34.3%) of 35 patients had sonographic signs of capillary leakage. Most (85%) patients with capillary leakage had classical DF. Capillary leak was diagnosed in 32% of primary dengue cases and in 40% of secondary dengue cases (P = 0.69). The two patients given a diagnosis of dengue hemorrhagic fever had primary infections. The high prevalence of capillary leakage among travelers, most of them with primary exposure to dengue, calls into question the importance of secondary infection in causing capillary leakage in dengue infection.

[Rickettsia africae infection among participants in a women's safari to South Africa]

PREFACE

In recent years infections with Rickettsia africae (African tick bite fever) have become a common and important cause of febrile illness among travelers returning from Sub-Saharan Africa, primarily from South Africa.

METHODS

A prospective observational study, involving 671 participants in safaris to South Africa during 2008.

RESULTS

Nine participants (1.34%) were diagnosed with African tick bite fever. The symptoms included fever, headache, muscle pain, lymphadenopathy, vesicular rash, and an eschar. Lack of familiarity with the disease led to an incorrect diagnosis and delayed treatment with doxycycline in a number of cases.

CONCLUSIONS

African tick bite fever is frequent among Israeli travelers to Sub-Saharan Africa. Travelers should be counseled on tick bite prevention. Increased awareness of the disease among Israeli physicians may prevent diagnostic delays.

[The profile of Israeli travelers to developing countries: perspectives of a travel clinic]

BACKGROUND

The number of Israeli travelers is increasing, including the number of travelers to developing countries.

AIM

This study aimed to characterize the profile of Israeli travelers to developing countries.

METHODS

Data regarding demographics, travel destinations, trip duration and the purpose of travel were collected on travelers attending the pre-travel clinic at the Sheba Medical Center during a period of 9 years.

RESULTS

Between the dates 1/1/1999 and 31/12/2007, 42,771 travelers presented for consultation at the Sheba Medical Center pre-travel clinic. The average age was 30.8 +/- 13.4 years and 54% of the travelers were males. The female proportion increased from 42% in 1999 to 49% in 2006. There was a steady increase in the number of travelers attending our clinic, except in 2003 (coinciding with the SARS epidemic). Post-army backpackers (20-25 year-old age group) were only 43% of the travelers. Children (<18 years), and elderly (>60 years) comprised 4.4% and 4.6% of the travelers, respectively. The favorite destinations were Asia (55%), followed by Latin America (27%) and Africa (13%). The distribution of travel destinations varied significantly during the study period. Of note is the sharp decline in travel to Africa following the terrorist attack in Mombassa, Kenya (November 2002). The median trip duration changed during the study period, from 30 to 45 days, between 1999-2004 and 2005-2007 respectively. The majority (87%) of voyagers traveled for pleasure, 6% went for business, and 7% were representatives of governmental organizations.

CONCLUSION

This study found an increasing diversity in the traveler population (more women, more children and older travelers) and more diversity in travel destinations. Disease outbreaks and terrorist attacks had transient negative impacts on the number of travelers.

Travel-related schistosomiasis acquired in Laos

Twelve Israeli travelers acquired schistosomiasis in Laos during 2002-2008, and 7 of them had acute schistosomiasis. The patients were probably exposed to Schistosoma mekongi in southern Laos, an area known to be endemic for schistosomiasis. Four possibly were infected in northern Laos, where reports of schistosomiasis are rare.