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Residual malaria transmission dynamics varies across The Gambia despite high coverage of control interventions

Mwesigwa, Julia; Achan, Jane; Di Tanna, Gian Luca; Affara, Muna; Jawara, Musa; Worwui, Archibald; Hamid-Adiamoh, Majidah; Kanuteh, Fatoumatta; Ceesay, Sainey; Bousema, Teun; Drakeley, Chris; Grietens, Koen Peeters; Lindsay, Steve W.; Van geertruyden, Jean-Pierre; D’Alessandro, Umberto

Residual malaria transmission dynamics varies across The Gambia despite high coverage of control interventions Thumbnail


Julia Mwesigwa

Jane Achan

Gian Luca Di Tanna

Muna Affara

Musa Jawara

Archibald Worwui

Majidah Hamid-Adiamoh

Fatoumatta Kanuteh

Sainey Ceesay

Teun Bousema

Chris Drakeley

Koen Peeters Grietens

Jean-Pierre Van geertruyden

Umberto D’Alessandro


Over the last decades, malaria has declined substantially in The Gambia but its transmission has not been interrupted. In order to better target control interventions, it is essential to understand the dynamics of residual transmission. This prospective cohort study was conducted between June 2013 and April 2014 in six pairs of villages across The Gambia. Blood samples were collected monthly during the transmission season (June-December) from all residents aged ≥6 months (4,194 individuals) and then in April (dry season). Entomological data were collected monthly throughout the malaria transmission season. Ownership of Long-Lasting Insecticidal Nets was 71.5% (2766/3869). Incidence of malaria infection and clinical disease varied significantly across the country, with the highest values in eastern (1.7/PYAR) than in central (0.2 /PYAR) and western (0.1/PYAR) Gambia. Malaria infection at the beginning of the transmission season was significantly higher in individuals who slept outdoors (HR = 1.51, 95% CI: 1.02–2.23, p = 0.04) and in those who had travelled outside the village (HR = 2.47, 95% CI: 1.83–3.34, p <0.01). Sub-patent infections were more common in older children (HR = 1.35, 95% CI: 1.04–1.6, p <0.01) and adults (HR = 1.53, 95% CI: 1.23–1.89, p<0.01) than in younger children. The risk of clinical malaria was significantly higher in households with at least one infected individual at the beginning of the transmission season (HR = 1.76, p<0.01). Vector parity was significantly higher in the eastern part of the country, both in the south (90.7%, 117/129, p<0.01) and the north bank (81.1%, 227/280, p<0.01), than in the western region (41.2%, 341/826), indicating higher vector survival. There is still significant residual malaria transmission across The Gambia, particularly in the eastern region. Additional interventions able to target vectors escaping Long-Lasting Insecticidal Nets and indoor residual spraying are needed to achieve malaria elimination.


Mwesigwa, J., Achan, J., Di Tanna, G. L., Affara, M., Jawara, M., Worwui, A., …D’Alessandro, U. (2017). Residual malaria transmission dynamics varies across The Gambia despite high coverage of control interventions. PLoS ONE, 12(11), Article e0187059.

Journal Article Type Article
Acceptance Date Oct 12, 2017
Online Publication Date Nov 2, 2017
Publication Date Nov 2, 2017
Deposit Date Nov 29, 2017
Publicly Available Date Nov 29, 2017
Journal PLoS ONE
Publisher Public Library of Science
Peer Reviewed Peer Reviewed
Volume 12
Issue 11
Article Number e0187059


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Copyright Statement
© 2017 Mwesigwa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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