A Critical Assessment of Vector Control for Dengue Prevention (original) (raw)
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Journal of Medical Entomology, 2009
Despite tremendous efforts by public health organizations in dengue-endemic countries, it has proven difÞcult to achieve effective and sustainable control of the primary dengue virus vector Aedes aegypti (L.) and to effectively disrupt dengue outbreaks. This problem has multiple root causes, including uncontrolled urbanization, increased global spread of dengue viruses, and vector and dengue control programs not being provided adequate resources. In this forum article, we give an overview of the basic elements of a vector and dengue control program and describe a continuous improvement cyclical model to systematically and incrementally improve control program performance by regular efforts to identify ineffective methods and inferior technology, and then replacing them with better performing alternatives. The Þrst step includes assessments of the overall resource allocation among vector/dengue control program activities, the efÞcacy of currently used vector control methods, and the appropriateness of technology used to support the program. We expect this will reveal that 1) some currently used vector control methods are not effective, 2) resource allocations often are skewed toward reactive vector control measures, and 3) proactive approaches commonly are underfunded and therefore poorly executed. Next steps are to conceptualize desired changes to vector control methods or technologies used and then to operationally determine in pilot studies whether these changes are likely to improve control program performance. This should be followed by a shift in resource allocation to replace ineffective methods and inferior technology with more effective and operationally tested alternatives. The cyclical and self-improving nature of the continuous improvement model will produce locally appropriate management strategies that continually are adapted to counter changes in vector population or dengue virus transmission dynamics. We discuss promising proactive vector control approaches and the continued need for the vector and dengue control community to incorporate emerging technologies and to partner with academia, business and the community-at-large to identify new solutions that reduce dengue.
Vector Control for Prevention of Dengue: Current Status and Future Strategies
When implemented properly, vector control can be an effective strategy for preventing mosquito-borne disease. Yet dengue control failures continue to be the norm rather than the exception. Reliance on prescribed control strategies and targets continues despite a clear understanding that the complex dynamics of dengue virus transmission is inconsistent with universal efficacy. Promising advances in control technology are on the horizon, but it is unlikely these will be effective for use either in isolation or across all epidemiological situations. Locally-adaptive control strategies that combine available tools in a manner suitable for the particular situation will increase the uptake, efficacy, and impact of dengue vector control programs. Widespread adoption of a locally-adaptive approach to dengue vector control will require a paradigm shift from current strategies (1). For vector control programs and personnel to effectively move from broadly-prescribed guidelines to autonomous d...
Building the evidence base for dengue vector control: searching for certainty in an uncertain world
Carolina Digital Repository (University of North Carolina at Chapel Hill), 2018
This review discusses biological and chemical methods for dengue vector control, using recently emerging summary evidence, meta-analyses and systematic reviews to conclude on practical public health recommendations for Aedes control, which is increasingly relevant in an era of widespread Chikungunya, yellow feer and Zika outbreaks. The analysis follows an a priori framework of systematic reviews by the authors on vector control methods, distinguishing vector control methods into biological, chemical and environmental methods. Findings of each published systematic review by the authors, following each individual vector control method, are summarised and compared in the discussion against the findings of existing meta-analyses covering all vector control methods. Analysing nine systematic reviews and comparing to two existing meta-analyses provided low-to-moderate evidence that the control of Aedes mosquitoes can be achieved using 1) chemical methods, particularly indoor residual spraying and insecticide treated materials, and 2) biological methods, where appropriate. The level of efficacy and community effectiveness of the methods in most studies analysed is low, as was the overall assessment of study quality. Furthermore, the results show that too optimise results, larvae and adults should be targeted simultaneously. The quality of service delivery is probably one of the most important features of this analysisand including high coverage. The analysis also highlights the urgent need for standards to guide the design and reporting of vector control studies, ensuring the validity and comparability of results. These studies should aim to include measurements of human transmission datawhere and when possible.
Interim Analysis of the Contribution of High-Level Evidence for Dengue Vector Control
The Southeast Asian journal of tropical medicine and public health, 2015
This interim analysis reviews the available systematic literature for dengue vector control on three levels: 1) single and combined vector control methods, with existing work on peridomestic space spraying and on Bacillus thuringiensis israelensis; further work is available soon on the use of Temephos, Copepods and larvivorous fish; 2) or for a specific purpose, like outbreak control, and 3) on a strategic level, as for example decentralization vs centralization, with a systematic review on vector control organization. Clear best practice guidelines for methodology of entomological studies are needed. There is a need to include measuring dengue transmission data. The following recommendations emerge: Although vector control can be effective, implementation remains an issue; Single interventions are probably not useful; Combinations of interventions have mixed results; Careful implementation of vector control measures may be most important; Outbreak interventions are often applied wi...
With the increased prevalence of dengue infection in tropical countries, concerned members of the public are now pressing their local health ministries to act immediately and effectively in managing the rising numbers of reported cases. This includes reviews of the methodologies and the effectiveness of current combative systems to find other possible novel approaches that might yield better results. One of those novel approaches is the integration of a parasite into mosquito vector, manipulating the parasite-host interaction to reduce the transmission of dengue in endemic hotspots. Another alternative is by Sanofi-Pasteur’s dengue vaccine that showed over 60.8% success rate in reducing severe dengue infection in children aged 9 - 16 during its final clinical implementation phase. This report will compare and contrast these two novel ideas to determine which of the approaches are more likely to be effective in the long run. The aspects covered will include the application, effectiveness, functionality, and problems with these approaches. The results could then be utilised by governments or organizations to select precise and effective methods in reducing the prevalence of dengue infections in their countries.
Prevention and Control Strategies to Counter Dengue Virus Infection
Frontiers in cellular and infection microbiology, 2017
Dengue is currently the highest and rapidly spreading vector-borne viral disease, which can lead to mortality in its severe form. The globally endemic dengue poses as a public health and economic challenge that has been attempted to suppress though application of various prevention and control techniques. Therefore, broad spectrum techniques, that are efficient, cost-effective, and environmentally sustainable, are proposed and practiced in dengue-endemic regions. The development of vaccines and immunotherapies have introduced a new dimension for effective dengue control and prevention. Thus, the present study focuses on the preventive and control strategies that are currently employed to counter dengue. While traditional control strategies bring temporary sustainability alone, implementation of novel biotechnological interventions, such as sterile insect technique, paratransgenesis, and production of genetically modified vectors, has improved the efficacy of the traditional strategi...
Global Health Action
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.
Dengue: Challenges for Policy Makers and Vaccine Developers
Current Infectious Disease Reports, 2014
Because of the increasing incidence, geographic expansion and economic burden of dengue transmission, dengue poses major challenges to policy makers. A vaccine against dengue is urgently needed, but vaccine development has been hampered by the lack of an appropriate animal model, poor understanding of correlates of successful human immunity, the fear of immune enhancement, and viral interference in tetravalent combinations. The most suitable target epitopes for vaccines, as well as the role of nonstructural proteins remain elusive. The chimeric yellow fever bonebased live attenuated dengue vaccine is furthest in development, but initial efficacy results have been disappointing. Lessons learnt from this failure will affect the design of future trials, and increase the urgency to identify the best epitope and immune correlates. Dengue vaccine introduction will not be the only strategy to combat dengue, but needs to be "packaged" with novel vector control approaches, with community-based interventions to reduce the number of breeding sites, and reducing the case fatality rate by improving case management.