Seasonal dynamics of Anopheles stephensi and its implications for mosquito detection and emergent malaria control in the Horn of Africa
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Invasion of the malaria vector Anopheles stephensi across the Horn of Africa threatens control efforts across the continent, particularly in urban settings where the vector is able to proliferate. Malaria transmission is primarily determined by the abundance of dominant vectors, which often varies seasonally with rainfall. However, it remains unclear how An. stephensi abundance changes throughout the year, despite this being a crucial input to surveillance and control activities. We collate longitudinal catch data from across its endemic range to better understand the vector's seasonal dynamics and explore the implications of this seasonality for malaria surveillance and control across the Horn of Africa. Our analyses reveal pronounced variation in seasonal dynamics, the timing and nature of which are poorly predicted by rainfall patterns. Instead, they are associated with temperature and patterns of land use; frequently differing between rural and urban settings. Our results show that timing entomological surveys to coincide with rainy periods is unlikely to improve the likelihood of detecting An. stephensi. Integrating these results into a malaria transmission model, we show that timing indoor residual spraying campaigns to coincide with peak rainfall offers little improvement in reducing disease burden compared to starting in a random month. Our results suggest that unlike other malaria vectors in Africa, rainfall may be a poor guide to predicting the timing of peaks in An. stephensi-driven malaria transmission. This highlights the urgent need for longitudinal entomological monitoring of the vector in its new environments given recent invasion and potential spread across the continent.
Date Issued
2023-02-21
Date Acceptance
2023-01-20
Citation
Proceedings of the National Academy of Sciences of USA, 2023, 120 (8), pp.1-9
ISSN
0027-8424
Publisher
National Academy of Sciences
Start Page
1
End Page
9
Journal / Book Title
Proceedings of the National Academy of Sciences of USA
Volume
120
Issue
8
Copyright Statement
Copyright © 2023 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution Licence 4.0 (CC BY).
License URL
Sponsor
Medical Research Council (MRC)
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/36791102
Grant Number
MR/R015600/1
Subjects
Anopheles stephensi
epidemiology
malaria ecology
population dynamics
urban malaria
Animals
Humans
Malaria
Anopheles
Seasons
Mosquito Vectors
Africa
Mosquito Control
Publication Status
Published
Coverage Spatial
United States
Article Number
e2216142120
Date Publish Online
2023-02-15