Louis Loutan

Options for Field Diagnosis of Human African Trypanosomiasis

SUMMARY Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense or T. b. rhodesiense remains highly prevalent in several rural areas of sub-Saharan Africa and is lethal if left untreated. Therefore, accurate tools are absolutely required for field diagnosis. For T. b. gambiense HAT, highly sensitive tests are available for serological screening but the sensitivity of parasitological confirmatory tests remains insufficient and needs to be improved. Screening for T. b. rhodesiense infection still relies on clinical features in the absence of serological tests available for field use. Ongoing research is opening perspectives for a new generation of field diagnostics. Also essential for both forms of HAT is accurate determination of the disease stage because of the high toxicity of melarsoprol, the drug most widely used during the neurological stage of the illness. Recent studies have confirmed the high accuracy of raised immunoglobulin M levels in the cerebrospinal fluid for the staging of T. b. gambiense HAT, and a promising simple assay (LATEX/IgM) is being tested in the field. Apart from the urgent need for better tools for the field diagnosis of this neglected disease, improved access to diagnosis and treatment for the population at risk remains the greatest challenge for the coming years.

Urbanisation and infectious diseases in a globalised world

Summary The world is becoming urban. The UN predicts that the worlds urban population will almost double from 3·3 billion in 2007 to 6·3 billion in 2050. Most of this increase will be in developing countries. Exponential urban growth is having a profound effect on global health. Because of international travel and migration, cities are becoming important hubs for the transmission of infectious diseases, as shown by recent pandemics. Physicians in urban environments in developing and developed countries need to be aware of the changes in infectious diseases associated with urbanisation. Furthermore, health should be a major consideration in town planning to ensure urbanisation works to reduce the burden of infectious diseases in the future.

Travel and migration associated infectious diseases morbidity in Europe, 2008

BackgroundEuropeans represent the majority of international travellers and clinicians encountering returned patients have an essential role in recognizing, and communicating travel-associated public health risks.MethodsTo investigate the morbidity of travel associated infectious diseases in European travellers, we analysed diagnoses with demographic, clinical and travel-related predictors of disease, in 6957 ill returned travellers who presented in 2008 to EuroTravNet centres with a presumed travel associated condition.ResultsGastro-intestinal (GI) diseases accounted for 33% of illnesses, followed by febrile systemic illnesses (20%), dermatological conditions (12%) and respiratory illnesses (8%). There were 3 deaths recorded; a sepsis caused by Escherichia coli pyelonephritis, a dengue shock syndrome and a Plasmodium falciparum malaria.GI conditions included bacterial acute diarrhea (6.9%), as well as giardiasis and amebasis (2.3%). Among febrile systemic illnesses with identified pathogens, malaria (5.4%) accounted for most cases followed by dengue (1.9%) and others including chikungunya, rickettsial diseases, leptospirosis, brucellosis, Epstein Barr virus infections, tick-borne encephalitis (TBE) and viral hepatitis. Dermatological conditions were dominated by bacterial infections, arthropod bites, cutaneous larva migrans and animal bites requiring rabies post-exposure prophylaxis and also leishmaniasis, myasis, tungiasis and one case of leprosy. Respiratory illness included 112 cases of tuberculosis including cases of multi-drug resistant or extensively drug resistant tuberculosis, 104 cases of influenza like illness, and 5 cases of Legionnaires disease. Sexually transmitted infections (STI) accounted for 0.6% of total diagnoses and included HIV infection and syphilis. A total of 165 cases of potentially vaccine preventable diseases were reported. Purpose of travel and destination specific risk factors was identified for several diagnoses such as Chagas disease in immigrant travellers from South America and P. falciparum malaria in immigrants from sub-Saharan Africa. Travel within Europe was also associated with health risks with distinctive profiles for Eastern and Western Europe.ConclusionsIn 2008, a broad spectrum of travel associated diseases were diagnosed at EuroTravNet core sites. Diagnoses varied according to regions visited by ill travellers. The spectrum of travel associated morbidity also shows that there is a need to dispel the misconception that travel, close to home, in Europe, is without significant health risk.

Multicenter EuroTravNet/GeoSentinel Study of Travel-related Infectious Diseases in Europe

We analyzed prospective data on 17,228 European patients who sought treatment at GeoSentinel sites from 1997 to 2007. Gastrointestinal illness (particularly in tourists), fever (those visiting friends and relatives [VFRs]), and skin disorders (in tourists) were the most common reasons for seeking medical care. Diagnoses varied by country of origin, region visited, or categories of travelers. VFRs who returned from sub-Saharan Africa and Indian Ocean islands were more likely to experience falciparum malaria than any other group. Multiple correspondence analysis identified Italian, French, and Swiss VFRs and expatriate travelers to sub-Saharan Africa and Indian Ocean Islands as most likely to exhibit febrile illnesses. German tourists to Southeast and south-central Asia were most likely to seek treatment for acute diarrhea. Non-European travelers (12,663 patients from other industrialized countries) were less likely to acquire certain travel-associated infectious diseases. These results should be considered in the practice of travel medicine and development of health recommendations for European travelers.

Inactivated virosome hepatitis A vaccine

Immunopotentiating reconstituted influenza virosomes (IRIV) are efficient carrier systems for small virion particles such as hepatitis A virus (HAV). We evaluated immunogenicity and tolerability of an IRIV-HAV vaccine and the effectiveness of a booster by immunising 104 healthy HAV seronegative volunteers. A single dose was highly immunogenic, since 98% of volunteers had seroconverted after 2 weeks. Anti-HAV titres remained high, with 100% seroconversion rate 1 year later, when the booster was given. The vaccine was effective, with a 22-fold increase in geometric mean titres 1 month later. No serious adverse reactions were observed.

Importance of patients' perceptions and general practitioners' recommendations in understanding missed opportunities for immunisations in Swiss adults.

Over the last decades, tremendous efforts have been made to strengthen childhood immunisation programs. However, the burden of influenza and pneumococcal infections remains disturbingly high in adults and elderly. We conducted a cross-sectional self-administered mail survey to identify characteristics associated with low use of recommended vaccines in adult patients attending routine primary care appointments in Switzerland. Tetanus vaccination was reported by 84% of respondents aged 16-34, and by only 42% of respondents aged 65 or more. For influenza and pneumococcal vaccination, of high-risk patients (age > or =65 or history of diabetes, kidney, heart, or chronic pulmonary disease), only 41% were on schedule for influenza and 6% for pneumococcal vaccination. Compared with patients from the German- and Italian-speaking areas of the country, patients from the French-speaking region were more likely to report past immunisation against influenza and pneumococcal disease or a recent physicians recommendation for immunisation against influenza, but equally likely to have ever refused influenza vaccination. For all three diseases, area of residence, physicians recommendation for immunisation, and patients perceived usefulness of vaccination were independently and significantly associated with vaccination status. Although patients opinion is an important determinant of vaccination coverage in adults, lack of physicians encouragement accounted for most missed vaccination opportunities in this study. The higher vaccination coverage among patients from the French-speaking area suggests that the promotion campaigns carried out in this region effectively improved influenza vaccine use. Interventions designed to increase vaccination coverage in adults must help providers incorporate immunisation in routine health care.

Treatment of visceral leishmaniasis in south-eastern Nepal: decreasing efficacy of sodium stibogluconate and need for a policy to limit further decline

Sodium stibogluconate (SSG) is the first-line therapy for visceral leishmaniasis (VL) in south-eastern Nepal. Recent studies from the neighbouring state of Bihar, India, have shown a dramatic fall in cure rates with treatment failure occurring in up to 65% of VL patients treated with SSG. A prospective study was conducted at a tertiary-level hospital located in south-eastern Nepal from July 1999 to January 2001. Parasitologically proven kala-azar patients with no previous history of treatment for VL were treated with SSG 20 mg/kg/d for 30 d which was extended to 40 d in those with persistent positive parasitology. Of the 110 patients who completed SSG therapy and were assessed at 1 and 6 months, definite cure was achieved in 99 patients (90%) and SSG failure occurred in 11 patients (10%). Except for the presence of hepatomegaly and a lower platelet count there was no clinical or laboratory baseline characteristic associated with treatment failure. A significantly lower cure rate (76%, P = 0.03) was observed in patients from the district of Saptari, which borders the antimony-resistant VL areas of Bihar. The efficacy of SSG as a first-line treatment for VL in south-eastern Nepal was still satisfactory, except for the patients living closer to the antimony-resistant VL areas of India. These findings indicate that the spread of resistance to antimonials is already taking place in Nepal and that a policy to control further spread should be urgently implemented.

Dermatologic conditions of the ill returned traveler: an analysis from the GeoSentinel Surveillance Network.

BACKGROUND Skin disorders are common in travelers. Knowledge of the relative frequency of post-travel-related skin disorders, including their geographic and demographic risk factors, will allow for effective pre-travel counseling, as well as improved post-travel diagnosis and therapeutic intervention. METHODS We performed a retrospective study using anonymous patient demographic, clinical, and travel-related data from the GeoSentinel Surveillance Network clinics from January 1997 through February 2006. The characteristics of these travelers and their itineraries were analyzed using SAS 9.0 statistical software. RESULTS A skin-related diagnosis was reported for 4594 patients (18% of all patients seen in a GeoSentinel clinic after travel). The most common skin-related diagnoses were cutaneous larva migrans (CLM), insect bites including superinfected bites, skin abscess, and allergic reaction (38% of all diagnoses). Arthropod-related skin diseases accounted for 31% of all skin diagnoses. Ill travelers who visited countries in the Caribbean experienced the highest proportionate morbidity due to dermatologic conditions. Pediatric travelers had significantly more dog bites and CLM and fewer insect bites compared with their adult counterparts; geriatric travelers had proportionately more spotted fever and cellulitis. CONCLUSIONS Clinicians seeing patients post-travel should be alert to classic travel-related skin diseases such as CLM as well as more mundane entities such as pyodermas and allergic reactions. To prevent and manage skin-related morbidity during travel, international travelers should avoid direct contact with sand, soil, and animals and carry a travel kit including insect repellent, topical antifungals, and corticosteroids and, in the case of extended and/or remote travel, an oral antibiotic with ample coverage for pyogenic organisms.

Congenital Transmission of Chagas Disease in Latin American Immigrants in Switzerland

International migration has changed the epidemiologic patterns of Chagas disease. Recently, 2 cases of Chagas disease transmitted from Latin American women to their newborns were diagnosed in Geneva, Switzerland. A retrospective study to detect Chagas disease showed a prevalence of 9.7% among 72 Latin American women tested during pregnancy in Switzerland.

Prevalence, Clinical Staging and Risk for Blood-Borne Transmission of Chagas Disease among Latin American Migrants in Geneva, Switzerland

Background Migration of Latin Americans to the USA, Canada and Europe has modified Chagas disease distribution, but data on imported cases and on risks of local transmission remain scarce. We assessed the prevalence and risk factors for Chagas disease, staged the disease and evaluated attitudes towards blood transfusion and organ transplant among Latin American migrants in Geneva, Switzerland. Methodology/Principal Findings This cross-sectional study included all consecutive Latin American migrants seeking medical care at a primary care facility or attending two Latino churches. After completing a questionnaire, they were screened for Chagas disease with two serological tests (Biomérieux ELISA cruzi; Biokit Bioelisa Chagas). Infected subjects underwent a complete medical work-up. Predictive factors for infection were assessed by univariate and multivariate logistic regression analysis.1012 persons (females: 83%; mean age: 37.2 [SD 11.3] years, Bolivians: 48% [n = 485]) were recruited. 96% had no residency permit. Chagas disease was diagnosed with two positive serological tests in 130 patients (12.8%; 95%CI 10.8%–14.9%), including 127 Bolivians (26.2%; 95%CI 22.3%–30.1%). All patients were in the chronic phase, including 11.3% with cardiac and 0.8% with digestive complications. Predictive factors for infection were Bolivian origin (OR 33.2; 95%CI 7.5–147.5), reported maternal infection with T. cruzi (OR 6.9; 95%CI 1.9–24.3), and age older than 35 years (OR 6.7; 95%CI 2.4–18.8). While 22 (16.9%) infected subjects had already donated blood, 24 (18.5%) and 34 (26.2%) considered donating blood and organs outside Latin America, respectively. Conclusions Chagas disease is highly prevalent among Bolivian migrants in Switzerland. Chronic cardiac and digestive complications were substantial. Screening of individuals at risk should be implemented in nonendemic countries and must include undocumented migrants.