Zika: Affordable, scalable, low-technology transfluthrin emanators for protecting against transmission in low-income countries
Lead Research Organisation:
Liverpool School of Tropical Medicine
Department Name: UNLISTED
Abstract
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Technical Summary
While Zika transmission in Africa has been historically enzoonotic, the new pandemic virus
lineage spreading across Asia and Latin America has adapted to transmission betweens
humans [1,2]. Diverse Aedes, Culex, Mansonia and Anopheles mosquitoes may act as
vectors, but pandemic urban transmission across Africa, Asia and Latin America appears
predominantly mediated by Aedes aegypti and Ae. albopictus [3-7]. Existing repellent
products for protecting against such day-biting mosquitoes, especially while active outdoors,
only last hours, days or weeks per dose or application. Sustaining continuous protection is
therefore impractical, and repeated replacement is unaffordable to low-income populations.
We recently developed a low-technology emanator [8], which releases repellent transfluthrin
vapour more slowly, providing at least 4 months of >90% protection against night-biting
Culex and Anopheles mosquitoes in urban Dar es Salaam, Tanzania, despite the presence of
considerable pyrethroid resistance [9]. This novel emanator consists only of a Hessian fabric
strip, which can be safely treated and re-treated by any individual, community, program or
local manufacturer [8,9]. Furthermore, equivalent efficacy and durability has since been
achieved with a 10-fold lower transfluthrin dosage of only 1ml, costing only £0.09 per
treatment. We have also recently developed a new electric grid trap for measuring attack
rates of mosquitoes, which prevents exposure of human volunteers to potentially infectious
bites [10]. We therefore propose to apply this novel trapping device to demonstrate that this
new repellent technology provides =6 months of =80% protection against day-biting Aedes
aegypti, probably the most important vector of pandemic Zika transmission globally.
lineage spreading across Asia and Latin America has adapted to transmission betweens
humans [1,2]. Diverse Aedes, Culex, Mansonia and Anopheles mosquitoes may act as
vectors, but pandemic urban transmission across Africa, Asia and Latin America appears
predominantly mediated by Aedes aegypti and Ae. albopictus [3-7]. Existing repellent
products for protecting against such day-biting mosquitoes, especially while active outdoors,
only last hours, days or weeks per dose or application. Sustaining continuous protection is
therefore impractical, and repeated replacement is unaffordable to low-income populations.
We recently developed a low-technology emanator [8], which releases repellent transfluthrin
vapour more slowly, providing at least 4 months of >90% protection against night-biting
Culex and Anopheles mosquitoes in urban Dar es Salaam, Tanzania, despite the presence of
considerable pyrethroid resistance [9]. This novel emanator consists only of a Hessian fabric
strip, which can be safely treated and re-treated by any individual, community, program or
local manufacturer [8,9]. Furthermore, equivalent efficacy and durability has since been
achieved with a 10-fold lower transfluthrin dosage of only 1ml, costing only £0.09 per
treatment. We have also recently developed a new electric grid trap for measuring attack
rates of mosquitoes, which prevents exposure of human volunteers to potentially infectious
bites [10]. We therefore propose to apply this novel trapping device to demonstrate that this
new repellent technology provides =6 months of =80% protection against day-biting Aedes
aegypti, probably the most important vector of pandemic Zika transmission globally.
Publications
| Description | Combating Zika and Future Threats: A Grand Challenge for Development |
| Amount | $948,454 (USD) |
| Funding ID | AID-OAA-F-16-00095 |
| Organisation | United States Agency for International Development |
| Sector | Public |
| Country | United States |
| Start | 09/2016 |
| End | 09/2018 |
| Title | Transfluthrin emanator |
| Description | The further evaluations against Zika/Dengue vectors in Tanzania, and against malaria vectors in Kenya have been funded by MRC. Additional ongoing development in Tanzania and end-user evaluations in Haiti are funded by USAID through their initiative for Combating Zika and Future Threats. Through this additional USAID support, we have now successfully engaged Bayer as our commercial partner, who have provided us with an emulsifiable concentrate formulation of transfluthrin, which we are now evaluating for comparison against our previous bespoke formulation. Assuming equivalent efficacy and durability is demonstrated, this new formulation is suitable for manufacture at scale and could be registered as a product for mass distribution and/or consumer sales through purely private sector delivery mechanisms. |
| Type | Preventative Intervention - Physical/Biological risk modification |
| Current Stage Of Development | Refinement. Non-clinical |
| Year Development Stage Completed | 2018 |
| Development Status | Under active development/distribution |
| Impact | Several other additional projects are now spinning off related to the same base technology. |
| URL | https://www.usaid.gov/sites/default/files/documents/1864/Combating-Zika-and-Future-Threats-Nominee-S... |