Genetic & Symbiont Strategies for Controlling Vector Borne Disease

Lead Research Organisation: University of Glasgow
Department Name: College of Medical, Veterinary &Life Sci

Abstract

Vector-borne diseases such as malaria, dengue and Zika have devastating impact in many developing countries, and in the absence of effective vaccines for most of these diseases, novel control tools are much needed. This network focuses on two highly promising approaches: genetic modification and the use of heritable endosymbionts. Both require the rearing and release of insect disease vectors with the aim of suppressing their populations or blocking the transmission of pathogens. They are highly targeted, species specific strategies, which (depending on the specific form employed) may only require one short intervention phase rather than repeated applications, thus providing major advantages over insecticides in terms of environmental impact and cost effectiveness. Some, for example Wolbachia, are already starting to be deployed in a number of countries.

This Network aims, for the first time, to draw together individuals from a broad range of scientific disciplines engaged in developing and deploying these approaches to foster knowledge exchange, methodological and technological sharing, and stimulate innovative collaborative research projects that will lay the foundation for new approaches or more effective implementation of those currently being developed. Importantly, given the potential impact of these approaches in developing countries, this Network will help to consolidate and expand the links between leading UK scientists and excellent researchers based in disease-endemic countries.

The themes to be covered by the network will be: vector-pathogen interactions; genetic modification technologies; gene drive systems; sterility and sex determination; Wolbachia and virus transmission blocking; other endosymbionts and parasite transmission blocking; vector population biology / male ecology and behaviour; population modelling; best practise for community engagement and field release trials; and impact assessment and cost-benefit analyses.

This will be a fully open network, open to new members throughout, and we will actively seek to recruit new expertise into the field to complement that of the starting group of members. The Network co-Directors, Manager and Management Board will oversee the network and evaluate applications for pump-priming research awards (up to one year duration) for novel projects from members, along with a larger number of short training and technology exchange visits between members' groups. The Network will organize and advertise three annual UK meetings, offering travel bursaries to support attendance. Three regional meetings will also be organised in SE Asia, Africa, and South America, concentrating on strategies that are field-ready and aiming to bring together scientists with policy makers.

The network will, by bringing together groups developing genetic and symbiont-based vector control systems, improve community interactions through the exchange of information, reagents, expertise and personnel (especially early stage researchers). It will create a forum to bring together UK and developing country members working on strategy implementation, allowing pooling of experience and improved linkages, and bring genetic and symbiont strategies to new researchers, policy makers and stakeholders. The network will facilitate transfer of technologies and symbiont approaches developed in mosquitoes to other disease vector systems, and bring together molecular biologists, ecologists and modellers. It will pump-prime novel project areas based on promising ideas or preliminary data, with an emphasis on rapid, light-touch review, providing an excellent platform for further longer-term funding. It will support the development of high quality grant proposals, through shared community expertise, and prioritise novelty in the research it supports.

Technical Summary

The network focuses on two highly promising new approaches for controlling vector-borne disease: genetic modification and the use of heritable endosymbionts. Both require the rearing and release of insect disease vectors with the aim of suppressing their populations or blocking the transmission of pathogens. They are highly targeted, species specific strategies, which (depending on the specific form employed) may only require one short intervention phase rather than repeated applications, thus providing major advantages over insecticides in terms of environmental impact and cost effectiveness. Some, for example Wolbachia, are already starting to be deployed in a number of countries.

This Network aims to draw together individuals from a broad range of scientific disciplines engaged in developing and deploying these approaches to foster knowledge exchange, methodological and technological sharing, and stimulate innovative collaborative research projects that provide a foundation for new approaches or would allow more effective implementation. Importantly, given the potential impact of these approaches in developing countries, this Network will help to consolidate and expand the links between leading UK scientists and excellent researchers based in disease-endemic countries.

The themes to be covered by the network will be: vector-pathogen interactions; genetic modification technologies; gene drive systems; sterility and sex determination; Wolbachia and virus transmission blocking; other endosymbionts and parasite transmission blocking; vector population biology / male ecology and behaviour; population modelling; best practise for community engagement and field release trials; and impact assessment and cost-benefit analyses.

This will be a fully open network, open to new members throughout, and we will actively seek to recruit new expertise into the field to complement that of the starting group of members.

Planned Impact

The Network will develop a foundation for the implementation of highly promising new strategies for blocking disease transmission by insect vectors, using genetic or symbiont-based control. The primary beneficiaries who stand to gain from this will be the inhabitants of countries in Africa, Southeast Asia and Central / South America that suffer from the devastating effects of parasitic vector-borne diseases such as malaria and trypanosomiasis, viral diseases such as dengue and Zika, and diseases that impact food production such as cassava mosaic virus. New vector-borne infections also continue to emerge regularly, and these strategies can also build resilience to future potential vector-borne epidemics. Affected communities will benefit from wider implementation of these strategies by improved health / reduced infant mortality. There can also be associated improvement in prospects for economic development, both through reducing major health burdens on the workforce through days lost, and allowing major improvements in agricultural output.

These strategies often do not require continuous intervention / resource investment - once the construct or symbiont is taken to a sufficient threshold population frequency it will increase further and then be maintained at very high frequency in the long term. Thus they can be a highly cost-effective interventions, without the need to continuously mobilize limited health care resources and without causing environmental damage. They have great potential to make a transformative impact on health (both human and veterinary) in tropical and sub-tropical regions where vector borne diseases have a huge impact, and have proven very difficult to control by conventional means. Rapid emergence and spread of vector insecticide resistance, coupled with insect behavioural changes to avoid coming into contact with insecticides, means that new control strategies are desperately needed for many of these diseases.

The network will support research aimed at assisting the creation of new control strategies, to extend the reach of existing symbiont and genetic strategies that are starting to be deployed, and aiding exchange of information between and among researchers, policy makers, stakeholders and communities in developing countries. Some of these approaches are already being tested in the field, particularly Wolbachia and transgenic sterile male releases. Thus there is considerable short-term benefit to be accrued in terms of disease control, by broadening the geographical range of uptake of these new approaches. Longer term benefits will come through acceleration in the development of new strategies (such as gene drive approaches and the use of new symbionts or target vectors) and support for highly promising early-stage ideas that might otherwise struggle to attract funding without preliminary data. Beside the genetic and symbiont approaches, furthering understanding of disease epidemiology and vector biology will be priority areas for the Network, of benefit to the implementation of more traditional, chemical-based control programmes.

The network will foster research on genetic & symbiont-based control tools that can lead to reduced human and animal disease burden / improvement in agriculture. Pathways to this end include the application of existing genetic & symbiont systems to new disease vector systems; raised awareness of genetic & symbiont approaches among stakeholders; improved capacity to deploy these control methods; development and assessment of novel genetic & symbiont-based approaches; enhanced tools to evaluate likely performance against existing control methods; and better understanding of potential barriers to effective implementation such as ethical, infrastructure, ecological and community.

Publications

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