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Movement rates of African malaria vectors and their implications in models of vector control interventions

English title Movement rates of African malaria vectors and their implications in models of vector control interventions
Applicant Moore Sarah
Number 163473
Funding scheme Project funding (Div. I-III)
Research institution Abt. öff. Gesundheitswesen und Epidemiologie Schweizerisches Tropen- und Public Health-Institut
Institution of higher education University of Basel - BS
Main discipline Methods of Epidemiology and Preventive Medicine
Start/End 01.01.2016 - 31.05.2019
Approved amount 429'000.00
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All Disciplines (2)

Discipline
Methods of Epidemiology and Preventive Medicine
Mathematics

Keywords (5)

mathematical modelling; entomology; Anopheles; malaria; Mosquito dispersal

Lay Summary (German)

Lead
Der Reproduktionszyklus von Muecken verlangt im Wechsel den Besuch von geeigneten Brutplaetzen und Wirbeltieren fuer Blutmahlzeiten. Die Erforschung der Flugruten von Muecken kann deshalb zum besseren Verstaendnis der Uebertragungswege von Krankheiten wie zum Beispiel Malaria beitragen. Bis jetzt ist wenig ueber die Flugruten von Malariamuecken bekannt. Die hier vorliegende Studie will den Einfluss oekologischer Faktoren sowie den Einfluss von Kontrollmassnahmen auf die Flugbewegungen von Muecken erforschen.
Lay summary

Die Entwicklung vieler Mueckenschutzmassnahmen ist zur Zeit in vollem Gang. Das gilt fuer verbesserte Varianten behandelter Mueckennetze genauso wie fuer neuartige Mueckenabwehrstoffe und Geruchskoederfallen. Um die Wirksamkeit von Kontrollmassnahmen zu beurteilen werden normalerweis die Ergebnisse kleiner Studien auf groessere Szenarien uebertragen. Die Aussagekraft von mathematischen Modellen welche die Wirksamkeit von Kontrollmassnahmen vorraussagen, ist durch unser Unwissen ueber Wechselwirkungen zwischen Kontrollmassnahmen und den Flugbewegungen von Muecken begrenzt.  

Dieses Projekt benutzt eine neue Methode um Muecken zu kennzeichnen sobald sie schluepfen. Dann werden taeglich Muecken in Gebieten mit und ohne Kontrollmassnahmen  eingefangen um zu sehen wie sie sich in jenen Gebieten bewegen.  Diese Information kann dann in mathematische Modelle von Mueckenflugbewegungen einfliessen und dazu beitragen die Wechselwirkung zwischen Kontrollmassnahmen und Flugruten zu verstehen. 

Die Studie verbindet Mueckenoekologie, mathematische Modelle und Epidemiologie. Ein verbessertes Verstaendnis von Mueckenbewegungen und deren Wechselwirkung mit Kontrollmassnahmen  wird dazu beitragen zielgerichtete Abwehrstrategien zu gestalten.

 

Direct link to Lay Summary Last update: 26.11.2015

Lay Summary (English)

Lead
To reproduce, mosquitoes continually move between aquatic larval habitats and vertebrate blood sources needed to develop eggs. Investigating mosquito movement will therefore enhance our understanding of the transmission dynamics of diseases like malaria that are passed between humans and mosquitoes. Yet, little is know about the dispersal of malaria transmitting mosquitoes. This study will estimate the ecological determinants of mosquito movement rates and the impact of mosquito control interventions upon their dispersal.
Lay summary

Lay Summary

Many interventions to control mosquito disease vectors are currently under development. These include improved versions of established interventions like insecticidal mosquito nets and new interventions such as spatial repellents and odour-baited mosquito traps. Traditionally, the efficacy of interventions in real-world environments is extrapolated from small-scale experiments. However, uncertainties in our understanding of mosquito dispersal, and thus the size of the area the interventions have an effect, limit the potential of predictive modelling of vector control interventions.

This project will use a new method to mark mosquitoes as they emerge from their breeding sites and recapture them daily to see how far they disperse, in areas with and without interventions. Mathematical models of mosquito dispersal will be developed and run with data from the field to see how dispersal impacts upon the overall effectiveness of mosquito control interventions.

Scientific and social context

The study combines mosquito ecology, mathematical modelling and epidemiology.  A better understanding of mosquito movement and its relationship with mosquito control interventions will guide targeted disease control strategies. 

 

Direct link to Lay Summary Last update: 26.11.2015

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
Ifakara Health Institute Tanzania (Africa)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
BOVA Network - Modelling workshop Talk given at a conference MATHEMATICAL MODELLING OF MOSQUITO MOVEMENT FOR MALARIA VECTOR CONTROL 07.01.2019 Durham University , Great Britain and Northern Ireland Denz Adrian;
11th European Conference on Mathematical and Theoretical Biology Talk given at a conference MATHEMATICAL MODELLING OF MOSQUITO MOVEMENT FOR MALARIA VECTOR CONTROL 27.07.2018 Lisbon, Portugal Denz Adrian;


Self-organised

Title Date Place
Mosquito movement modelling meeting 28.05.2018 University of Basel , Switzerland

Associated projects

Number Title Start Funding scheme
125316 Estimating transition rates for epidemiological models of endemic Plasmodium vivax malaria 01.04.2009 Project funding (Div. I-III)
57165 Development of spatial statistical methods for modeling point- referenced data in malaria epidemiology. 01.12.1999 Project funding (Div. I-III)
105994 Predicting efficacy and cost-effectiveness of malaria control interventions in Africa using dynamic models 01.10.2004 Project funding (Div. I-III)
43527 Development of statistical approaches for estimating incidence and risk factors of morbidity from tropical disease: analyses and validation with existing epidemiological data. 01.10.1995 Project funding (Div. I-III)
147286 Modelling spatio-temporal dynamics of malaria and mortality to develop optimised interventions and surveillance tools in Africa 01.04.2014 r4d (Swiss Programme for Research on Global Issues for Development)
59380 Dynamics of malaria parasites in areas of high transmission 01.09.2000 Project funding (Div. I-III)

Abstract

Many interventions against mosquito vectors of disease are currently under development. These include new insecticidal compounds applied in established interventions like indoor residual spraying (IRS) and insecticide treated mosquito nets (ITNs). Also under development are novel or un-established interventions such as spatial repellents (SR) and odour-baited mosquito traps (OBT). Each of these interventions have effects over larger areas than the immediate vicinity to which they are applied, because mosquitoes move between aquatic breeding sites and vertebrate hosts to complete their life cycle. As a consequence, impacts on mosquito populations under natural conditions can be far greater than estimated from standard tests carried out at small-scale. These community/area/ or mass effects driven by mosquito movement mean that large-scale field-testing of vector control interventions raises both statistical and operational issues that have a spatial dimension, different from those of clinical trials of health interventions that only protect directly treated individuals, such as chemotherapy or chemoprophylaxis. To accelerate product development, registration and implementation and make interventions more cost efficient, it is especially important to understand how a mosquito control intervention with specific performance criteria, as measured in small-scale experiments (such as mortality or repellency) will perform in the real world. This can be achieved by modelling relationships between small-scale and real-world performance indicators, to enable effects on transmission and public health outcomes to be extrapolated from small high-throughput experiments without the need to repeat larger scale field trials. However uncertainties in our understanding of mosquito dispersal limit the potential of predictive modelling of vector control interventions and little is known about whether/how best to target such interventions in real-world environments that are heterogeneous in the spatial distributions of mosquito breeding-sites, of humans and other hosts, and of existing interventions. This project will comprise field experiments, based on fluorescent marking of emergent mosquitoes to estimate the key determinants of Anopheles movement rates (both while host-seeking and ovipositing) in real-world landscapes near Bagamoyo, Tanzania, and the impact of interventions upon them. Mathematical models of mosquito dispersal will be developed, and parameterised with these field data, as well as with the results of previous small-scale semi-field experiments, field experiments in experimental huts, and large-scale field trials of SRs, and of OBTs. These models will be validated against a large field trial of OBTs in Rusinga, Kenya and a large field trial of SRs in Tanzania.The calibrated models will be linked to models of malaria transmission and disease and will thus contribute to predictions of the likely impacts of different strategies for field deployment of entomological interventions in heterogeneous environments, on mosquito population densities and on disease in humans.
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