Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination

Brady, O.J.; Godfray, C.J.; Tatem, A.J.; Gething, P.W.; Cohen, J.M.; McKenzie, F.E.; Perkins, T.A.; Reiner Jr., R.C.; Tusting, L.S.; Sinka, M.E.; Moyes, C.L.; Eckhoff, P.A.; Scott, T.W.; Lindsay, S.W.; Hay, S.I.; Smith, D.L.

doi:10.1093/trstmh/trv113

Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination

Brady, O.J.; Godfray, C.J.; Tatem, A.J.; Gething, P.W.; Cohen, J.M.; McKenzie, F.E.; Perkins, T.A.; Reiner Jr., R.C.; Tusting, L.S.; Sinka, M.E.; Moyes, C.L.; Eckhoff, P.A.; Scott, T.W.; Lindsay, S.W.; Hay, S.I.; Smith, D.L.

Authors

O.J. Brady

C.J. Godfray

A.J. Tatem

P.W. Gething

J.M. Cohen

F.E. McKenzie

T.A. Perkins

R.C. Reiner Jr.

L.S. Tusting

M.E. Sinka

C.L. Moyes

P.A. Eckhoff

T.W. Scott

Professor Steve Lindsay s.w.lindsay@durham.ac.uk
Professor

S.I. Hay

D.L. Smith

Abstract

Background Major gains have been made in reducing malaria transmission in many parts of the world, principally by scaling-up coverage with long-lasting insecticidal nets and indoor residual spraying. Historically, choice of vector control intervention has been largely guided by a parameter sensitivity analysis of George Macdonald's theory of vectorial capacity that suggested prioritizing methods that kill adult mosquitoes. While this advice has been highly successful for transmission suppression, there is a need to revisit these arguments as policymakers in certain areas consider which combinations of interventions are required to eliminate malaria. Methods and Results Using analytical solutions to updated equations for vectorial capacity we build on previous work to show that, while adult killing methods can be highly effective under many circumstances, other vector control methods are frequently required to fill effective coverage gaps. These can arise due to pre-existing or developing mosquito physiological and behavioral refractoriness but also due to additive changes in the relative importance of different vector species for transmission. Furthermore, the optimal combination of interventions will depend on the operational constraints and costs associated with reaching high coverage levels with each intervention. Conclusions Reaching specific policy goals, such as elimination, in defined contexts requires increasingly non-generic advice from modelling. Our results emphasize the importance of measuring baseline epidemiology, intervention coverage, vector ecology and program operational constraints in predicting expected outcomes with different combinations of interventions.

Citation

Brady, O., Godfray, C., Tatem, A., Gething, P., Cohen, J., McKenzie, F., …Smith, D. (2016). Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination. Transactions of The Royal Society of Tropical Medicine and Hygiene, 110(2), 107-117. https://doi.org/10.1093/trstmh/trv113

Journal Article Type	Article
Acceptance Date	Dec 8, 2015
Online Publication Date	Feb 28, 2016
Publication Date	Feb 1, 2016
Deposit Date	Mar 1, 2016
Publicly Available Date	Mar 14, 2016
Journal	Transactions of The Royal Society of Tropical Medicine and Hygiene
Print ISSN	0035-9203
Electronic ISSN	1878-3503
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Volume	110
Issue	2
Pages	107-117
DOI	https://doi.org/10.1093/trstmh/trv113

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© The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.