Evaluation of a Rapid Dipstick (Crystal VC) for the Diagnosis of Cholera in Zanzibar and a Comparison with Previous Studies

BackgroundThe gold standard for the diagnosis of cholera is stool culture, but this requires laboratory facilities and takes at least 24 hours. A rapid diagnostic test (RDT) that can be used by minimally trained staff at treatment centers could potentially improve the reporting and management of cholera outbreaks.MethodsWe evaluated the Crystal VC™ RDT under field conditions in Zanzibar in 2009. Patients presenting to treatment centers with watery diarrhea provided a stool sample for rapid diagnostic testing. Results were compared to stool culture performed in a reference laboratory. We assessed the overall performance of the RDT and evaluated whether previous intake of antibiotics, intravenous fluids, location of testing, and skill level of the technician affected the RDT results.ResultsWe included stool samples from 624 patients. Compared to culture, the overall sensitivity of the RDT was 93.1% (95%CI: 88.7 to 96.2%), specificity was 49.2% (95%CI: 44.3 to 54.1%), the positive predictive value was 47.0% (95%CI: 42.1 to 52.0%) and the negative predictive value was 93.6% (95%CI: 89.6 to 96.5%). The overall false positivity rate was 50.8% (213/419); fieldworkers frequently misread very faint test lines as positive.ConclusionThe observed sensitivity of the Crystal VC RDT evaluated was similar compared to earlier versions, while specificity was poorer. The current version of the RDT could potentially be used as a screening tool in the field. Because of the high proportion of false positive results when field workers test stool specimens, positive results will need to be confirmed with stool culture

Assessment and comparative analysis of a rapid diagnostic test (Tubex®) for the diagnosis of typhoid fever among hospitalized children in rural Tanzania

Background: Typhoid fever remains a significant health problem in many developing countries. A rapid test with a performance comparable to that of blood culture would be highly useful. A rapid diagnostic test for typhoid fever, Tubex®, is commercially available that uses particle separation to detect immunoglobulin M directed towards Salmonella Typhi O9 lipopolysaccharide in sera.Methods: We assessed the sensitivity and specificity of the Tubex test among Tanzanian children hospitalized with febrile illness using blood culture as gold standard. Evaluation was done considering blood culture confirmed S. Typhi with non-typhi salmonella (NTS) and non - salmonella isolates as controls as well as with non-salmonella isolates only.Results: Of 139 samples tested with Tubex, 33 were positive for S. Typhi in blood culture, 49 were culture-confirmed NTS infections, and 57 were other non-salmonella infections. Thirteen hemolyzed samples were excluded. Using all non - S. Typhi isolates as controls, we showed a sensitivity of 79% and a specificity of 89%. When the analysis was repeated excluding NTS from the pool of controls we showed a sensitivity of 79% and a specificity of 97%. There was no significant difference in the test performance using the two different control groups (p > 0.05).Conclusion: This first evaluation of the Tubex test in an African setting showed a similar performance to those seen in some Asian settings. Comparison with the earlier results of a Widal test using the same samples showed no significant difference (p > 0.05) for any of the performance indicators, irrespective of the applied control group

Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies

BACKGROUND: The diagnosis of typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi (S. typhi). However, a more rapid, simpler, and cheaper diagnostic method would be very useful especially in developing countries. The Widal test is widely used in Africa but little information exists about its reliability. METHODS: We assessed the performance of the Widal tube agglutination test among febrile hospitalized Tanzanian children. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of various anti-TH and -TO titers using culture-confirmed typhoid fever cases as the "true positives" and all other febrile children with blood culture negative for S. typhi as the "true negatives." RESULTS: We found that 16 (1%) of 1,680 children had culture-proven typhoid fever. A single anti-TH titer of 1:80 and higher was the optimal indicator of typhoid fever. This had a sensitivity of 75%, specificity of 98%, NPV of 100%, but PPV was only 26%. We compared our main findings with those from previous studies. CONCLUSION: Among febrile hospitalized Tanzanian children with a low prevalence of typhoid fever, a Widal titer of > or = 1:80 performed well in terms of sensitivity, specificity, and NPV. However a test with improved PPV that is similarly easy to apply and cost-efficient is desirable

Social norm change in the context of a development assistance project in Madagascar

International audienc

Greenwashing and Bluewashing in Black Friday-Related Sustainable Fashion Marketing on Instagram

Growing awareness of the fashion industry’s negative impact on people and the environment has led to considerable growth of the sustainable fashion market. At the same time, Black Friday purchases increase annually as the sales event develops into a global phenomenon. As sustainable fashion brands are choosing to participate in the event, many communicate their offers via the social media platform Instagram. To gain a competitive advantage and maintain their sustainable corporate images, some brands use greenwashing and/or bluewashing strategies. The first part of this study explores which strategies were employed in Instagram content posted by sustainable brands, using quantitative and qualitative content analysis. We propose a research-based model of nine greenwashing/bluewashing strategies. The second part of the study examines predictive factors for consumer evaluations of Black Friday ads by sustainable brands, using an online survey and a stepwise multiple regression analysis. Findings show that consumers’ critical attitude towards Black Friday and high ad skepticism predict positive evaluations while sustainable purchase behavior predicts negative evaluations. These insights suggest that ‘sustainable’ Black Friday campaigns may appeal to consumers who show a general concern for the environment and issues of social sustainability, but not to those who exhibit actual sustainable behavior

Sustaining sustainability science: The role of established inter-disciplines

The establishment of new interdisciplinary fields such as ecological economics, human ecology or technology assessment can be interpreted as a logical consequence of striving for new sustainability sciences that address current global, multi-dimensional and multi-scale challenges. These set out to bridge the gap between the natural and the social sphere, between scientific analysis and societal action. This paper aims at re-assessing the contribution of established inter-disciplines to sustainable development. Journal articles of ecological economics, technology assessment and science and technology studies are evaluated and compared along several proposed features of sustainability science. The results converge in two crucial aspects. (1) Concise societal or political recommendations are not part of present day 'normal science', be it a disciplinary or an explicitly interdisciplinary research context. (2) Participatory exercises are rarely applied as a socio-politically embedded practice, despite a high interest in such exercises as an object of study and discussion.Sustainability science Technology assessment Ecological economics Science and technology studies Inter-disciplines

Managing complex adaptive systems: a co-evolutionary perspective on natural research management

The overexploitation of natural resources and the increasing number of social conflicts following from their unsustainable use point to a wide gap between the objectives of sustainability and current resource management practices. One of the reasons for the difficulties to close this gap is that for evolving complex systems like natural and socio-economic systems, sustainability cannot be a static objective. Instead sustainable development is an open evolutionary process of improving the management of social–ecological systems, through better understanding and knowledge. Therefore, natural resource management systems need to be able to deal with different temporal, spatial and social scales, nested hierarchies, irreducible uncertainty, multidimensional interactions and emergent properties. The co-evolutionary perspective outlined in this paper serves as heuristic device to map the interactions settled in the networks between the resource base, social institutions and the behaviour of individual actors. For this purpose we draw on ideas from complex adaptive systems theory, evolutionary theory and evolutionary economics. Finally, we outline a research agenda for a co-evolutionary approach for natural resource management systems

Stuck in the Present: A Human Lack of Ability to Visualise (Different) Needs in the Future May Hamper Timely Implementation of AAL and Supportive Technology

Cities face an evident demographic change, making assistive technologies (AAL) an interesting choice to support older adults to autonomously age in place. Yet, supportive technologies are not as widely spread as one would expect. Hence, we investigate the surroundings of older adults living in Vienna and analyse their “socio relational setup”, considering their social integration and psychophysical state compared to others (health, fitness, activeness, contentedness). Method: Our data included 245 older adults (age: M = 74, SD = 6654) living in their own homes (2018–2020 with different grades of needing support). We calculated univariate and multivariate models regressing the socio-relational setup on the change of routines, technology attitude, mobility aid use, internet use, subjective age, openness to move to an institutional care facility in the future, and other confounding variables. Results: We found a strong correlation between all categories (health, fitness, activeness, contentedness) of older adults comparing themselves to their peers. Among others, they are significantly related to institutional care openness, which implies that participants who felt fitter and more active than their peers were less clear in visualising their future: unpleasant circumstances of ageing are suppressed if the current life circumstances are perceived as good. This is an example of cognitive dissonance