[Risk communication in travel medicine]. / Communication du risque en médecine des voyages.

Recommendations for malaria prevention for travelers planning a trip in medium to low risk countries differ between countries, despite the fact that people are exposed to the same risk in the travelled country. Decision aids have been developed and tested in a population of travelers planning a trip in such countries n order to present travelers the various prevention options and involve them in the decision. The use of the decision aid showed that he majority of people choose not to take chemoprophylaxis and that they could motivate their choice with valid reasons. The development of decision aids based on recognized quality criteria is foreseen; these will allow to improving the relevance of the recommendations and enable travelers to choose a prevention option that will be the closest to their values and preferences while following to the principles of medical ethics.

[Acute schistosomiasis: lessons learned from a cohort of 42 exposed travelers]. / Schistosomiase aiguë au retour de voyage. Enseignements tirés d'une cohorte de 42 voyageurs exposés.

Acute schistosomiasis is a regularly encountered disease in travelers. Because of the temporal delay, its unspecific presentation and the spontaneous resolution, acute schistosomiasis can easily remain unrecognized by physicians who are not familiar with tropical pathologies. In December 2011, a female traveler was admitted to the hospital with undetermined fever after having returned from Madagascar where she bathed in fresh water. Acute schistosomiasis was diagnosed and infection was suspected among other travelers of her group. Seroconversion was confirmed among 78% of participants. This article intends to clarify the preventive and diagnostic strategies based on the lessons learned from this cluster of 42 travelers exposed to schistosomiasis.

[Yellow fever: new recommendations]. / Fièvre jaune: nouvelles recommandations.

Indication for yellow fever vaccination is not always easy to assess. The decision to immunize is not only based on the actual risk of the disease in a specific location, but also on public health considerations in the visited country (in order to respectively avoid epidemics in endemic countries or the introduction of the virus in zones where the vectors mosquitoes are present) and on travelers' risk factors for severe or even fatal vaccine adverse events. WHO has recently published new recommendations regarding vaccination against yellow fever after concluding that one dose of vaccine generates a life-long protection. This article tends to clarify the strategy to adopt in 2013 using cases frequently encountered in the practice of travel medicine.

[True and virtual risks of travellers]. / Mort des voyageurs: risques réels, risques virtuels.

Evidence-based information on travel associated mortality is scarce. Perception, intuition and the availability of interventions such as vaccinations and chemoprophylaxis often guide pre-travel advice. Important risks including accidents and cardiovascular events are not routinely included in pre-travel consultations although they cause more fatalities and costs than infectious diseases. The increased risk of sustaining a road accident in poor economy countries should always be mentioned. The general practitioner is further best placed to discuss possible problems of travellers with chronic diseases before travel.

[Hepatitis B and migrants: should we do better?]. / Hépatite B et migrants: doit-on mieux faire?

More than 5% of the world's population lives with chronic hepatitis B. Migrants, particularly asylum seekers, are mostly from middle and high endemic regions. In Switzerland, however, no systematic screening of chronic hepatitis B is proposed to them. In a resolution published in 2010 the WHO encourages vaccination, but also screening of people at risk, as well as care of infected individuals. On the basis of a study conducted in asylum seekers in the canton of Vaud, prevalence of Ac antiHBc is estimated at 42% and HBsAg at 8%. Possible screening strategies and care are discussed in the light of these data. Identifying infected migrants would give them access to medical care and therefore lower the rate of complications, as well as the transmission of the virus between migrants and the local population.

[Viral fevers from elsewhere]. / Fièvres virales d'ailleurs.

Some viruses are transmitted only in specific parts of the world and do not exist in Switzerland. However, the increase in intercontinental travels, the tendency of travelers to have activities in remote rural areas, the transportation (sometimes forbidden) of exotic animals, the climatic warming and the adaptation of viruses to new vectors produce an extension of viral diseases towards Northern countries. To improve the identification of these infections in travelers, but also in European autochthonous populations, it is necessary to know the clinical characteristics and the websites announcing the epidemics. Neurological or hemorrhagic signs should incite the clinician to suspect a viral hemorrhagic fever, diagnosis to be considered if the destination and chronology are compatible, strict isolation measures being necessary.

[Efficacy is good, impact is great]. / L'efficacité c'est bien, l'impact c'est top!

This article summarizes the different stages of research for the development of medical interventions and their specific characteristics in terms of design, population, resources, importance of results and scientific interest. The emphasis is focused on the two final stages of development, the effectiveness and the impact. An example from our own experience is given to illustrate the reduction of the effect of an intervention against malaria in young children at different stages of the development of the intervention, and the parallel decrease of the recognition by the scientific community of the importance of these results.

[The spirit of community medicine: students learning from students]. / Penser la médecine communautaire s'apprend avec les pairs.

At the University of Lausanne third-year medical students are given the task of spending a month investigating a question of community medicine. In 2009, four students evaluated the legitimacy of health insurers intervening in the management of depression. They found that health insurers put pressure on public authorities during the development of legislation governing the health system and reimbursement for treatment. This fact emerged during the scientific investigation led jointly by the team in the course of the "module of immersion in community medicine." This paper presents each step of their study. The example chosen illustrates the learning objectives covered by the module.

[Rapid diagnostic tests (RDT): the cure-all for the practitioner?]. / Tests diagnostiques rapides (TDR): la panacée pour le praticien?

Many rapid diagnostic tests (RDT) for the diagnosis of infectious diseases have been developed over the last 20 years. These allow (1) administering a treatment immediately in case of a potentially fatal disease, (2) prescribing a specific rather than presumptive treatment, (3) quickly introducing measures aimed at interrupting the transmission of the disease, (4) avoiding useless antibiotic treatments and (5) implementing a sequential diagnostic strategy to avoid extensive investigations. Using the example of malaria, a new strategy that includes a RDT as first-line emergency diagnostic tool and, when negative, delayed microscopy at the laboratory opening time is implemented in Lausanne since 1999. This strategy has been shown to be safe. Each TDR has its own characteristics that imperatively need to be known by the practitioner if he/she wants to use it in a rational way.

[How can serology contribute to the diagnosis of parasitic diseases?]. / Comment la sérologie peut-elle aider à l'établissement du diagnostic des parasites?

From a technical standpoint the most widely used tests for serology include the ELISA (enzyme linked immunosorbent assay), the IFA (indirect fluorescence assay), and the immunoblot. ELISA tests are widely used as screening assays since they harbor a high sensitivity. The main pitfall of serologies is the frequency of cross-reactions, especially between the different helminths. This is why positive results should be confirmed by a second test method with a higher specificity. Results need also to be put in the perspective of the patient history, clinical signs and laboratory findings. Serological tests are most appropriate when the parasite cannot be documented by direct examination (by eye or under the microscope) and during the pre-patent period. Serologies for parasites are also useful when an unexplained eosinophilia is present.