Robert Steffen

Background: Travellers’ diarrhea (TD) continues to be the most frequent health problem in travellers with destinations in lower income parts of the world as compared with where they reside, even if that risk has slightly decreased. Methods: A systematic review was published 18 months ago; now PubMed was searched for more recent publications relating to travel, diarrhea, epidemiology, incidence, risk. Results: A trend to decreasing incidence rates have been noted in this as compared with the last century, but TD remains frequent. The clinical picture varies from a trivial ailment to severe with subsequent hospitalization. Of great concern are long-term sequelae, particularly post-infectious irritable bowel syndrome. The most important risk factors are the destination and duration of exposure among the environmental factors, whereas the age is the most relevant host factor. Conclusions: Even if improved hygienic conditions in low-income countries often visited by travellers have resulted in slightly diminished incidence rates of TD, this remains a frequent health problem. Visitors to such destinations must be informed about that health risk and it is beneficial to equip them with instructions and a travel kit to enable them to some extent self-manage TD occurring abroad.

A few decades ago, travel medicine, or travel health as labelled by WHO, had to be developed from scratch as an interdisciplinary field to protect travelers from illness and accidents, and ultimately death. A variety of surveys have shed some light on travel health risks. However, much remains to be done to improve the reliability of the evidence on which advisors to travelers base their recommendations. Ongoing assessment and analysis with multicentre collaboration and modern tools to generate data are needed.

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." 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. 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. 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.

A patch vaccine containing heat-labile toxin (LT) from enterotoxigenic Escherichia coli (ETEC) has demonstrated to be beneficial in reducing the rate and severity of travelers' diarrhea in Latin America. To evaluate the efficacy of this transdermal vaccine system in an area with a different diarrheal pathogen profile, an additional phase 2 study was conducted in European travelers to India. For this multicenter, randomized, double-blinded, placebo-controlled field study 723 subjects were recruited; 603 (299 LT vaccine, 304 placebo) were included in the per-protocol-population (PPP). Although the LT patch induced a measurable LT immune response in recipients, it failed to protect against LT ETEC or all-cause diarrhea. In the PPP the incidence rate of diarrhea as per primary endpoint was 6.0% (18 of 299) in the vaccine group and 5.9% (18 of 304) in the placebo group. Additionally, lower than expected rates of LT ETEC diarrheas were observed in India. The vaccine delivery system frequently produced rash and pruritus at the site of application, long term hyperpigmentation persisted in a minority of LT recipients, and also few site reactions were noted in the placebo group. The evaluated patch vaccine failed to satisfy mainly with respect to protective efficacy. Noninvasive prophylactic agents against travelers' diarrhea, particularly vaccines against the most frequent pathogens, thus continue to be badly needed.

Die Erfahrung aus Massenveranstaltungen – üblicherweise von mehr als 25'000 Personen besucht – zeigt, dass deren etwa eine von Tausend eine der medizinischen Hilfsstellen konsultieren wird. Üblicherweise spielen Infektionskrankheiten hierbei eine untergeordnete Rolle; früher allerdings sind nach dem Hadsch in aller Welt unter anderem Ausbrüche von Meningokokken-Meningitis aufgetreten. Dank Impfungen und anderen Maßnahmen hat sich dies eindämmen lassen. Mehrheitlich ist die Belastung der Strukturen des regionalen Gesundheitswesens durch Unfälle und nicht übertragbare Krankheiten bedingt. Eine Mehrheit dieser Konsultationen betrifft Banalitäten. Persönliche und umgebungsbedingte Risikofaktoren können allerdings in einer dramatischen Steigerung der Rate der Konsultationen resultieren: Alter und vorbestehende Krankheiten spielen eine Rolle vor allem bei Pilgern (Hadsch, Lourdes), emotionale Faktoren beeinflussen das Verhalten und können allenfalls zu Aggressionen führen. Auch Alkohol und Drogen, letztlich ebenfalls die Dauer eines Events spielen hierbei eine zentrale Rolle. Extreme klimatische Verhältnisse, Hitze oder Kälte resultieren in oftmals dramatisch vermehrten Notfallkonsultationen. Die Infrastruktur muss der Volksmenge angepasst sein, insbesondere ist zu vermeiden, dass es in einem Nadelöhr zum Gedränge und Desaster kommt. Die Weltgesundheitsorganisation und andere interessierte Gremien haben in den letzten Jahren Richtlinien zur Prävention formuliert.

Background. Travelers' diarrhea (TD) remains a frequent travel‐associated infection. Between 4 and 32% of enteric infections were followed by a postinf

Incidence rates of travellers' diarrhoea (TD) need to be updated and risk factors are insufficiently known.

Influenza is the most frequent travel related infection preventable by universally available vaccines, but preventive measures were neglected until recently. Since the spread of pandemic (H1N1) 2009, various public health measures have been promoted first to contain, then to mitigate, the pandemic. Some of these measures contradicted recommendations issued by the World Health Organization and were of questionable efficacy. However, travelers may benefit from targeted recommendations on influenza risk reduction (eg, by social distancing or immunization). These recommendations are particularly indicated for those with an increased personal risk profile and for those likely to be exposed to influenza patients.