Gambiense human African trypanosomiasis is a deadly disease that has been declining in incidence since the start of the Century, primarily due to increased screening, diagnosis and treatment of ...infected people. The main treatment regimen currently in use requires a lumbar puncture as part of the diagnostic process to determine disease stage and hospital admission for drug administration. Fexinidazole is a new oral treatment for stage 1 and non-severe stage 2 human African trypanosomiasis. The World Health Organization has recently incorporated fexinidazole into its treatment guidelines for human African trypanosomiasis. The treatment does not require hospital admission or a lumbar puncture for all patients, which is likely to ease access for patients; however, it does require concomitant food intake, which is likely to reduce adherence. Here, we use a mathematical model calibrated to case and screening data from Mushie territory, in the Democratic Republic of the Congo, to explore the potential negative impact of poor compliance to an oral treatment, and potential gains to be made from increases in the rate at which patients seek treatment. We find that reductions in compliance in treatment of stage 1 cases are projected to result in the largest increase in further transmission of the disease, with failing to cure stage 2 cases also posing a smaller concern. Reductions in compliance may be offset by increases in the rate at which cases are passively detected. Efforts should therefore be made to ensure good adherence for stage 1 patients to treatment with fexinidazole and to improve access to care.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Background
Gambiense human African trypanosomiasis (gHAT sleeping sickness) is a vector-borne disease that is typically fatal without treatment. Intensified, mainly medical-based, ...interventions in endemic areas have reduced the occurrence of gHAT to historically low levels. However, persistent regions, primarily in the Democratic Republic of Congo (DRC), remain a challenge to achieving the World Health Organization’s goal of global elimination of transmission (EOT).
Methods
We used stochastic models of gHAT transmission fitted to DRC case data and explored patterns of regional reporting and extinction. The time to EOT at a health zone scale (~100 000 people) and how an absence of reported cases informs about EOT was quantified.
Results
Regional epidemiology and level of active screening (AS) both influenced the predicted time to EOT. Different AS cessation criteria had similar expected infection dynamics, and recrudescence of infection was unlikely. However, whether EOT has been achieved when AS ends is critically dependent on the stopping criteria. Two or three consecutive years of no detected cases provided greater confidence of EOT compared with a single year (~66%–75% and ~82%–84% probability of EOT, respectively, compared with 31%–51%).
Conclusions
Multiple years of AS without case detections is a valuable measure to assess the likelihood that the EOT target has been met locally.
Abstract
As neglected tropical disease programs look to consolidate the successes of moving towards elimination, we need to understand the dynamics of transmission at low prevalence to inform ...surveillance strategies for detecting elimination and resurgence. In this special collection, modelling insights are used to highlight drivers of local elimination, evaluate strategies for detecting resurgence, and show the importance of rational spatial sampling schemes for several neglected tropical diseases (specifically schistosomiasis, soil-transmitted helminths, lymphatic filariasis, trachoma, onchocerciasis, visceral leishmaniasis, and gambiense sleeping sickness).
In this work, we address the economic and environmental optimization of the operations in a natural-gas-based petrochemical complex through multiobjective optimization. The site is represented by a ...mathematical model that includes linear and nonlinear simplified models for single equipment and plants to calculate site production levels, taking into account main operating variables, utility consumption, intermittent delivery, inventory level profiles and product distribution. The resulting multiperiod, mixed integer nonlinear programming (MINLP) models are implemented in GAMS. The bicriteria MINLP model is solved with the ε-constraint method. The obtained Pareto-optimal curve shows the trade-off between the economic and environmental aspects to pursuit sustainable operations of an existing integrated petrochemical complex. The environmental metrics is Global Warming Potential. ReCiPe is used for life cycle assessment and its 18 midpoint impact indicators and three end-point indicators are further analyzed for the petrochemical complex. The optimal solutions show that the environmental performance of the industrial cluster can be improved by a different distribution of processed raw material and intermediate products between the plants, as well as the means of transportation.
Gambiense human African trypanosomiasis is a deadly disease that has been declining in incidence since the start of the Century, primarily due to increased screening, diagnosis and treatment of ...infected people. The main treatment regimen currently in use requires a lumbar puncture as part of the diagnostic process to determine disease stage and hospital admission for drug administration. Fexinidazole is a new oral treatment for stage 1 and non-severe stage 2 human African trypanosomiasis. The World Health Organization has recently incorporated fexinidazole into its treatment guidelines for human African trypanosomiasis. The treatment does not require hospital admission or a lumbar puncture for all patients, which is likely to ease access for patients; however, it does require concomitant food intake, which is likely to reduce adherence. Here, we use a mathematical model calibrated to case and screening data from Mushie territory, in the Democratic Republic of the Congo, to explore the potential negative impact of poor compliance to an oral treatment, and potential gains to be made from increases in the rate at which patients seek treatment. We find that reductions in compliance in treatment of stage 1 cases are projected to result in the largest increase in further transmission of the disease, with failing to cure stage 2 cases also posing a smaller concern. Reductions in compliance may be offset by increases in the rate at which cases are passively detected. Efforts should therefore be made to ensure good adherence for stage 1 patients to treatment with fexinidazole and to improve access to care.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper addresses the optimal operation of a petrochemical complex under economic and environmental criteria. The site mathematical model includes linear and nonlinear simplified models for single ...plants to calculate site production taking into account main operating variables, intermittent deliveries and inventory variable profiles. The objective function considers the maximization of total profit and the minimization of environmental impact, subject to constraints on mass balances, bounds on product demands, equipment capacities and intermediate and final product storage tanks limitations. The environmental objective is measured with the global warming potential (GWP) and Eco-indicator 99 metrics according to the life cycle assessment procedures. The resulting mixed integer nonlinear programming (MINLP) models have been implemented in GAMS. The bi-criteria MINLP model is solved with the e-constraint method. The resulting pareto-optimal curve shows the tradeoff between the economic and environmental aspects to pursuit a sustainable operation of an existing integrated petrochemical complex. The optimal solution shows that polyethylene plants have the best environmental and economic performances in the entire complex. As compared to current situation, optimization results show that the petrochemical complex can satisfy product demands while improving the environmental behavior by decreasing greenhouse gases emissions in almost 26 %, from 1,018 to 750.42 kt CO2-eq/y.
Purpose
– The purpose of this paper is to analyse the effects of some political measures on entrepreneurship to promote economic growth and employment, specifically, R
&
D policies, training, ...elimination of administrative barriers, access to finance support and promotion of entrepreneurial culture.
Design/methodology/approach
– Seven hypotheses are tested developing a latent variables model with data from 13 European countries (Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Portugal, Spain, Sweden and UK) in 2012, using partial least squares estimation method.
Findings
– Greater expenditure on R
&
D by governments and universities, public investment in education and measures to stimulate entrepreneurial culture have a positive effect on entrepreneurship. Furthermore, countries with complex legal systems which regulate the start-up of an economic activity and where access to credit is complicated, present lower levels of entrepreneurship. Societies with a greater number of innovative entrepreneurs present higher levels of entrepreneurial activity and economic performance. Finally, human capital and entrepreneurial activity positively affect economic performance in the case of the European countries studied in the sample.
Practical implications
– The results obtained in the paper would facilitate the design of measures to stimulate to entrepreneurs and improve economic performance.
Originality/value
– Several factors, qualitative and quantitative, have been considered in the analysis that they have not traditionally included in the analysis of the entrepreneurship behaviour taking into account the role played by the policy makers measures to improve such behaviour.
Since the turn of the century, the global community has made great progress towards the elimination of gambiense human African trypanosomiasis (HAT). Elimination programs, primarily relying on ...screening and treatment campaigns, have also created a rich database of HAT epidemiology. Mathematical models calibrated with these data can help to fill remaining gaps in our understanding of HAT transmission dynamics, including key operational research questions such as whether integrating vector control with current intervention strategies is needed to achieve HAT elimination. Here we explore, via an ensemble of models and simulation studies, how including or not disease stage data, or using more updated data sets affect model predictions of future control strategies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Due to the COVID-19 pandemic, many key neglected tropical disease (NTD) activities have been postponed. This hindrance comes at a time when the NTDs are progressing towards their ambitious goals for ...2030. Mathematical modelling on several NTDs, namely gambiense sleeping sickness, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases (STH), trachoma, and visceral leishmaniasis, shows that the impact of this disruption will vary across the diseases. Programs face a risk of resurgence, which will be fastest in high-transmission areas. Furthermore, of the mass drug administration diseases, schistosomiasis, STH, and trachoma are likely to encounter faster resurgence. The case-finding diseases (gambiense sleeping sickness and visceral leishmaniasis) are likely to have fewer cases being detected but may face an increasing underlying rate of new infections. However, once programs are able to resume, there are ways to mitigate the impact and accelerate progress towards the 2030 goals.
Control of gambiense sleeping sickness relies predominantly on passive and active screening of people, followed by treatment.
Mathematical modeling explores the potential of 3 complementary ...interventions in high- and low-transmission settings.
Intervention strategies that included vector control are predicted to halt transmission most quickly. Targeted active screening, with better and more focused coverage, and enhanced passive surveillance, with improved access to diagnosis and treatment, are both estimated to avert many new infections but, when used alone, are unlikely to halt transmission before 2030 in high-risk settings.
There was general model consensus in the ranking of the 3 complementary interventions studied, although with discrepancies between the quantitative predictions due to differing epidemiological assumptions within the models. While these predictions provide generic insights into improving control, the most effective strategy in any situation depends on the specific epidemiology in the region and the associated costs.
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