Analyzing GeoSentinel surveillance data: a comparison of methods to explore acute gastrointestinal illness among international travelers

Gastrointestinal cell injury and perceived symptoms after running the Boston Marathon

Gastrointestinal (GI) disturbances are a prevalent cause of marathon related complaints, and in extreme cases can promote life-threatening conditions such as exertional heat stroke. Our aim was to study intestinal cell injury [via intestinal fatty acid binding protein (I-FABP)] and perceived GI distress symptoms among marathon runners. We also examined potential risk factors (e.g., inadequate sleep) that could exacerbate GI disturbances in healthy, trained endurance runners. This was a parallel mixed-methods study design. 2019 Boston Marathon participants were recruited via email and subjects completed surveys before the race describing demographics and training history. Participants completed a GI questionnaire to assess presence and severity of symptoms, a survey regarding risk factors (e.g., recent illness, medications) that could promote GI disturbances, and provided a urine sample at three time points (immediately pre-race, post-race, and 24-h post-race). Due to weather, blood samples were only collected immediately and 24-h post-race. A total of 40 runners (males: n = 19, age = 44.9 ± 10.8 years; females: n = 21, age = 44.8 ± 10.6 years) completed this study. I-FABP significantly decreased from post-race (3367.5 ± 2633.5 pg/mL) to 24-h post-race (1657.3 ± 950.7 pg/mL, t (39) = -4.228, p < .001, d = -.669). There was a significant difference in overall GI symptom scores across the three time points (F (2, 39) = 41.37, p < .001). The highest average score occurred post-race (.84 ± .68), compared to pre-race (.09 ± .12) and 24-h post-race (.44 ± .28). Post-race I-FABP (r = .31, p = .048) and post-race urine specific gravity (r = .33, p = .041) were significantly correlated with post-race GI symptom scores. Our study provides further support to the individualized nature of GI disturbances, with participants experiencing a wide range of risk factors that can influence the extent of GI damage and perceived symptoms during and after exercise.

Travellers' diarrhoea - prevention, trends and role of microbiome

OBJECTIVES

In this review, we present a contemporary look at the management of travellers' diarrhoea (TD), and we discuss the potential role of a microbiome as well as the administration of live microorganisms in order to prevent TD.

METHODS

We performed a comprehensive search using the PubMed and Web of Science databases for the period 2014-2021, looking for original and review articles on travellers' diarrhoea.

RESULTS

TD belongs among the most frequent illnesses experienced by travellers. For the most part, it is manifested as an acute yet self limiting condition, and only in a few cases proceeds to a prolonged form. Epidemiological analyses have shown that the majority of TD cases are caused by bacterial infections. In practice, pharmacological therapy is often used in the prevention and treatment of TD, since patients naturally seek preventive measures against the development of its severe course and its impact on planned activities. Bismuth salicylate is a strongly recommended TD prophylaxis but is not available on all European Union markets. Although the antibiotic prophylaxis is not generally recommended in guidelines, some antibiotic or chemotherapeutic agents are accessible over-the-counter in certain countries, and travellers are routinely encouraged to use them preventively. This routine can alter the microbiome of the traveller and promote the spread of drug resistant bacteria in their place of residence. Probiotic administration is considered safe, although the quality of evidence in favour of its prophylactic use in TD is currently low.

CONCLUSIONS

The challenge for public health authorities is to educate personnel that can directly influence the behaviour of travellers through safe and effective pharmacological alternatives to antibiotics. Manipulation of the gut microbiome using specific probiotic strains can represent a safe and promising intervention.

Novel tools for the surveillance and control of dengue: findings by the DengueTools research consortium

BACKGROUND

Dengue fever persists as a major global disease burden, and may increase as a consequence of climate change. Along with other measures, research actions to improve diagnosis, surveillance, prevention, and predictive models are highly relevant. The European Commission funded the DengueTools consortium to lead a major initiative in these areas, and this review synthesises the outputs and findings of this work conducted from 2011 to 2016. Research areas: DengueTools organised its work into three research areas, namely [1] Early warning and surveillance systems; [2] Strategies to prevent dengue in children; and [3] Predictive models for the global spread of dengue. Research area 1 focused on case-studies undertaken in Sri Lanka, including developing laboratory-based sentinel surveillance, evaluating economic impact, identifying drivers of transmission intensity, evaluating outbreak prediction capacity and developing diagnostic capacity. Research area 2 addressed preventing dengue transmission in school children, with case-studies undertaken in Thailand. Insecticide-treated school uniforms represented an intriguing potential approach, with some encouraging results, but which were overshadowed by a lack of persistence of insecticide on the uniforms with repeated washing. Research area 3 evaluated potential global spread of dengue, particularly into dengue-naïve areas such as Europe. The role of international travel, changing boundaries of vectors, developing models of vectorial capacity under different climate change scenarios and strategies for vector control in outbreaks was all evaluated.

CONCLUDING REMARKS

DengueTools was able to make significant advances in methods for understanding and controlling dengue transmission in a range of settings. These will have implications for public health agendas to counteract dengue, including vaccination programmes.

OUTLOOK

Towards the end of the DengueTools project, Zika virus emerged as an unexpected epidemic in the central and southern America. Given the similarities between the dengue and Zika viruses, with vectors in common, some of the DengueTools thinking translated readily into the Zika situation.

Travel-associated infection presenting in Europe (2008-12): an analysis of EuroTravNet longitudinal, surveillance data, and evaluation of the effect of the pre-travel consultation

BACKGROUND

Travel is important in the acquisition and dissemination of infection. We aimed to assess European surveillance data for travel-related illness to profile imported infections, track trends, identify risk groups, and assess the usefulness of pre-travel advice.

METHODS

We analysed travel-associated morbidity in ill travellers presenting at EuroTravNet sites during the 5-year period of 2008-12. We calculated proportionate morbidity per 1000 ill travellers and made comparisons over time and between subgroups. We did 5-year trend analyses (2008-12) by testing differences in proportions between subgroups using Pearson's χ(2) test. We assessed the effect of the pre-travel consultation on infection acquisition and outcome by use of proportionate morbidity ratios.

FINDINGS

The top diagnoses in 32 136 patients, ranked by proportionate morbidity, were malaria and acute diarrhoea, both with high proportionate morbidity (>60). Dengue, giardiasis, and insect bites had high proportionate morbidity (>30) as well. 5-year analyses showed increases in vector borne infections with significant peaks in 2010; examples were increased Plasmodium falciparum malaria (χ(2)=37·57, p<0·001); increased dengue fever (χ(2)=135·9, p<0·001); and a widening geographic range of acquisition of chikungunya fever. The proportionate morbidity of dengue increased from 22 in 2008 to 36 in 2012. Five dengue cases acquired in Europe contributed to this increase. Dermatological diagnoses increased from 851 in 2008 to 1102 in 2012, especially insect bites and animal-related injuries. Respiratory infection trends were dominated by the influenza H1N1 pandemic in 2009. Illness acquired in Europe accounted for 1794 (6%) of all 32 136 cases-mainly, gastrointestinal (634) and respiratory (357) infections. Migration within Europe was associated with more serious infection such as hepatitis C, tuberculosis, hepatitis B, and HIV/AIDS. Pre-travel consultation was associated with significantly lower proportionate morbidity ratios for P falciparum malaria and also for acute hepatitis and HIV/AIDS.

INTERPRETATION

The pattern of travel-related infections presenting in Europe is complex. Trend analyses can inform on emerging infection threats. Pre-travel consultation is associated with reduced malaria proportionate morbidity ratios and less severe illness. These findings support the importance and effectiveness of pre-travel advice on malaria prevention, but cast doubt on the effectiveness of current strategies to prevent travel-related diarrhoea.

FUNDING

European Centre for Disease Prevention and Control, University Hospital Institute Méditerranée Infection, US Centers for Disease Control and Prevention, and the International Society of Travel Medicine.