Travellers' diarrhea in children

Highly specific, multiplexed isothermal pathogen detection with fluorescent aptamer readout

Isothermal, cell-free, synthetic biology-based approaches to pathogen detection leverage the power of tools available in biological systems, such as highly active polymerases compatible with lyophilization, without the complexity inherent to live-cell systems, of which nucleic acid sequence based amplification (NASBA) is well known. Despite the reduced complexity associated with cell-free systems, side reactions are a common characteristic of these systems. As a result, these systems often exhibit false positives from reactions lacking an amplicon. Here we show that the inclusion of a DNA duplex lacking a promoter and unassociated with the amplicon fully suppresses false positives, enabling a suite of fluorescent aptamers to be used as NASBA tags (Apta-NASBA). Apta-NASBA has a 1 pM detection limit and can provide multiplexed, multicolor fluorescent readout. Furthermore, Apta-NASBA can be performed using a variety of equipment, for example, a fluorescence microplate reader, a qPCR instrument, or an ultra-low-cost Raspberry Pi-based 3D-printed detection platform using a cell phone camera module, compatible with field detection.

Soil-transmitted helminthiases in Nepal: Transmission boundaries and implications for local communities and international travelers

Soil transmitted helminthiasis (STHs) are endemic in Nepal but since the country territory is extremely heterogeneous, a multidisciplinary assessment is required to evaluate the risk of infection in different areas. Prevalence data were retrieved with systematic literature search and geographical coordinates were assigned to each survey site. Spatial stratification was then implemented considering land use and ecological parameters. STH transmission boundaries were tested after reference criteria and elevation was evaluated as additional predictor: the elevation threshold of 3057 m above sea level is demarking the STH transmission limit. Areas above this threshold are safe, but since lodging in at-risk sites is a compulsory stopover for international travelers, STH risk exposure should be considered for every travel to the country.

Travellers' diarrhoea-a survey of practice

BACKGROUND.

Travellers' diarrhoea (TD) is a common problem, affecting millions of tourists each year and creating a large economic burden. Risk factors for TD are known and guidelines exist to assist practitioners in advising travellers on how to prevent and treat TD. However, data are lacking regarding actual prescribing practices or approaches used in TD management. This study aims to establish a baseline which identifies uniformities and diversities in practice.

METHODS.

An online survey created using the SurveyMonkey tool was developed to test respondent approaches to TD pre-travel management. An invitation to participate in the survey was distributed early 2016 through selected Australian and New Zealand speciality travel medicine centres and through the electronic mailing list of the International Society of Travel Medicine (ISTM). Descriptive statistics and analyses using Chi Square analysis and two-sided Fishers exact tests for significance were used.

RESULTS.

Three hundred and sixty-four completed or partially completed surveys were collected from respondents in 23 countries. Approach to TD, antibiotic choice and management of four different clinical scenarios were assessed, with analyses focused on identifying significant differences in approach according to region of practice, professional background and level of experience. The responses to the clinical scenarios suggest most uniformity in recommended treatment strategies in clearly mild or severe disease, and greater variability in moderate disease.

CONCLUSIONS.

There is practice diversity in the discussion of preventative techniques and prescribing of self-treatment medications for TD, especially for moderate TD disease. Evidence-based guidelines that address the competing issues of patient health and morbidity vs the risk of colonization with resistant organisms may lead to more consistent antibiotic prescribing practices.

Summary of the Committee to Advise on Tropical Medicine and Travel (CATMAT) Statement on Travellers' Diarrhea

Background

Most travellers' diarrhea (TD) infections occur during travel to low- and middle-income countries. Type of travel, duration of stay, age of traveller and presence of certain medical conditions are important factors to consider for risk of TD. The Committee to Advise on Tropical Medicine and Travel (CATMAT) assembled a TD working group to develop recommendations on prevention and treatment of TD in travellers. This document is a summary of the Statement on Travellers' Diarrhea.

Methods

Following a systematic review of the literature, recommendations on the prevention and treatment of TD were developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to evaluate data quality, benefits and harms of the intervention, and values and preferences of the traveller. Other recommendations were based on a review of the literature and expert opinion.

Recommendations

Using the GRADE methodology, CATMAT concluded that oral cholera vaccine should not be routinely recommended to prevent TD in Canadian travellers. This recommendation was based on moderate quality data that showed this vaccine was not effective in preventing TD in travellers compared to placebo. Bismuth subsalicylate (BSS), fluoroquinolones or rifaximin are options for the prevention of TD based on high-quality data for BSS and fluoroquinolones and moderate evidence for rifaximin. For the treatment of TD, loperamide (alone or in combination with antibiotics), fluoroquinolones, azithromycin and rifaximin are all options, with varying degrees of data quality. Based on available evidence and expert opinion, CATMAT recommends handwashing or the use of hand sanitizer, as well as prudent choice and preparation of food and beverages as best practices for preventing diarrhea while travelling. At this time, a recommendation cannot be made for either the use of probiotics and prebiotics to prevent TD or the use of BSS to treat TD due to insufficient available evidence.

Conclusion

With the exception of BSS for prevention of TD (strong recommendation for use), CATMAT conditionally recommends the use of each of the other GRADE-evaluated preventive and therapeutic products assessed in this Statement. These CATMAT recommendations should be considered as options in the prevention and treatment of TD based on the particular situation of the traveller.

Advice for families traveling to developing countries with young children

Young children are most likely to travel to developing countries with their parents to visit relatives. Preparation for such travel must include careful counseling and optimal use of preventive vaccines and chemoprophylaxis. For infants and very young children, data defining safety and efficacy of these agents are often limited. However, accumulated experience suggests that young travelers may be managed similarly to older children and adults.