Indoor behaviour maps to guide arbovirus vector control

Summary

Aedes aegypti is the most important vector of dengue, Zika, yellow fever and chikungunya viruses to humans worldwide. It is abundant in urban environments but as it is notoriously difficult to control, outbreaks continue to place a major burden on communities that are powerless to protect themselves. Development of effective new tools to target Ae. aegypti and reduce the frequency and magnitude of arbovirus outbreaks is urgently needed.

It is well known that Aedes aegypti spend almost their entire adult life inside the human home but precisely where they rest when they are not biting is unknown. We propose to identify Ae. aegypti behaviours or events that can be targeted with simple low-cost tools or practices. Working in a semi-field system based in Recife, Brazil, our preliminary research indicates that resting Ae. aegypti have a strong preference for the lowest positions on interior walls within limited surface areas suitable for rapid insecticide treatment. If confirmed, this would dramatically reduce speed, cost and effectiveness of indoor insecticide treatments for this vector. We also investigated flight behaviour in African malaria mosquitoes, and using a similar approach, we identified novel behavioural activity that rapidly led to successful exploitation using a novel control tool.

We propose that with better knowledge of a vector's flying or resting behaviour, targeting with insecticides residues could be simpler, faster and more cost-effective. This proposal aims to use video tracking technology, developed by the applicants, to map the resting and flight patterns of Ae. aegypti within an experimental 'simulated home' environment, to identify key locations within the human home where this difficult vector can be targeted rapidly, effectively and safely.

Aedes aegypti is the most important vector of dengue, Zika, yellow fever and chikungunya viruses to humans worldwide. It is abundant in urban environments but as it is notoriously difficult to control, outbreaks continue to place a major burden on communities that are powerless to protect themselves. Development of effective new tools to target Ae. aegypti and reduce the frequency and magnitude of arbovirus outbreaks is urgently needed.

It is well known that Aedes aegypti spend almost their entire adult life inside the human home but precisely where they rest when they are not biting is unknown. We propose to identify Ae. aegypti behaviours or events that can be targeted with simple low-cost tools or practices. Working in a semi-field system based in Recife, Brazil, our preliminary research indicates that resting Ae. aegypti have a strong preference for the lowest positions on interior walls within limited surface areas suitable for rapid insecticide treatment. If confirmed, this would dramatically reduce speed, cost and effectiveness of indoor insecticide treatments for this vector. We also investigated flight behaviour in African malaria mosquitoes, and using a similar approach, we identified novel behavioural activity that rapidly led to successful exploitation using a novel control tool.

We propose that with better knowledge of a vector's flying or resting behaviour, targeting with insecticides residues could be simpler, faster and more cost-effective. This proposal aims to use video tracking technology, developed by the applicants, to map the resting and flight patterns of Ae. aegypti within an experimental 'simulated home' environment, to identify key locations within the human home where this difficult vector can be targeted rapidly, effectively and safely.

IMPACT SUMMARY

Reducing the burden of arboviral disease in javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions("ctl00$oSaveBar$btnSave", "", true, "", "", false, true))urban zones through improved vector control-
Dengue is the most common vector-borne viral disease worldwide. Yellow fever outbreaks occur regularly in Africa and the threat of large outbreaks in urban Latin America or even Asia remains very real. The frequency of outbreaks of chikungunya in human populations is increasing every year and this virus continues to spread to new geographical areas, including Europe. The explosive outbreak of Zika and the ensuing response by WHO attest to the magnitude of the threat posed by arboviruses transmitted by Aedes aegypti.
Any one of these infections alone would be considered of major importance; that one vector species is responsible for multiple serious infections is exceptional; that there is no proven effective method of vector control for preventing or responding to outbreaks of any of these infections is simply unacceptable. Consequently, development of effective new tools to target Ae. aegypti and reduce the frequency and magnitude of arbovirus outbreaks have been prioritised by WHO, USAID, DFID and numerous NGOs. The outputs will be of immediate value to such organisations by allowing the formulation of clear advice in guidelines for stakeholders in affected communities.
This proposal's aim is the advancement of basic knowledge of mosquito biology and behaviour, an essential step towards effective control. Hence, the impacts directly contribute to sustainable development goals 3 ("Ensure healthy lives and promote wellbeing...") and 11 ("Make cities inclusive, safe..."). Economic and societal impacts of the project's outputs would be in Asia and Latin America primarily, but value will extend into any community where this mosquito is a vector.

-Developing appropriate sustainable cost-effective control tools-
Not all vector control tools will be suitable for deployment in affected communities, as numerous issues surrounding user perception of efficacy and benefit, the frequency and cost of replenishment over time will influence the likelihood of routine, correct usage. The applicants' experience will ensure that the direction of the project always remains grounded in the realities of real world contexts.


For the private sector, the findings will be especially important in [re]defining target product profiles.

-Reducing insecticide quantities and risks-
Our goal is to design tools that deliver a range of effective insecticides in ways that reach the target pest species efficiently, whilst minimizing quantities of insecticide used and risks to users within and beyond the home.

-Improved capacity in Brazil-
Capacity strengthening is a cornerstone of LSTM's mission and the project will help to develop independent local scientists who will be part of the next generation of vector biologists in Brazil.