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Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control

After 2 decades of using insecticide-treated nets (ITNs) and improved case management, malaria burden in the historically-holoendemic Kilombero valley in Tanzania has significantly declined. We review key characteristics of the residual transmission and recommend options for improvement. Transmissio...

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Autores principales: Okumu, Fredros, Finda, Marceline
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079133/
https://www.ncbi.nlm.nih.gov/pubmed/33906218
http://dx.doi.org/10.1093/infdis/jiaa653
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author Okumu, Fredros
Finda, Marceline
author_facet Okumu, Fredros
Finda, Marceline
author_sort Okumu, Fredros
collection PubMed
description After 2 decades of using insecticide-treated nets (ITNs) and improved case management, malaria burden in the historically-holoendemic Kilombero valley in Tanzania has significantly declined. We review key characteristics of the residual transmission and recommend options for improvement. Transmission has declined by >10-fold since 2000 but remains heterogeneous over small distances. Following the crash of Anopheles gambiae, which coincided with ITN scale-up around 2005-2012, Anopheles funestus now dominates malaria transmission. While most infections still occur indoors, substantial biting happens outdoors and before bed-time. There is widespread resistance to pyrethroids and carbamates; An. funestus being particularly strongly-resistant. In short and medium-term, these challenges could be addressed using high-quality indoor residual spraying with nonpyrethroids, or ITNs incorporating synergists. Supplementary tools, eg, spatial-repellents may expand protection outdoors. However, sustainable control requires resilience-building approaches, particularly improved housing and larval-source management to suppress mosquitoes, stronger health systems guaranteeing case-detection and treatment, greater community-engagement and expanded health education.
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spelling pubmed-80791332021-04-30 Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control Okumu, Fredros Finda, Marceline J Infect Dis Supplement Articles After 2 decades of using insecticide-treated nets (ITNs) and improved case management, malaria burden in the historically-holoendemic Kilombero valley in Tanzania has significantly declined. We review key characteristics of the residual transmission and recommend options for improvement. Transmission has declined by >10-fold since 2000 but remains heterogeneous over small distances. Following the crash of Anopheles gambiae, which coincided with ITN scale-up around 2005-2012, Anopheles funestus now dominates malaria transmission. While most infections still occur indoors, substantial biting happens outdoors and before bed-time. There is widespread resistance to pyrethroids and carbamates; An. funestus being particularly strongly-resistant. In short and medium-term, these challenges could be addressed using high-quality indoor residual spraying with nonpyrethroids, or ITNs incorporating synergists. Supplementary tools, eg, spatial-repellents may expand protection outdoors. However, sustainable control requires resilience-building approaches, particularly improved housing and larval-source management to suppress mosquitoes, stronger health systems guaranteeing case-detection and treatment, greater community-engagement and expanded health education. Oxford University Press 2021-04-27 /pmc/articles/PMC8079133/ /pubmed/33906218 http://dx.doi.org/10.1093/infdis/jiaa653 Text en © World Health Organization, 2021. All rights reserved. The World Health Organization has granted the Publisher permission for the reproduction of this article. https://creativecommons.org/licenses/by/3.0/igo/This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 IGO License (https://creativecommons.org/licenses/by/3.0/igo/) which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Supplement Articles
Okumu, Fredros
Finda, Marceline
Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title_full Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title_fullStr Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title_full_unstemmed Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title_short Key Characteristics of Residual Malaria Transmission in Two Districts in South-Eastern Tanzania—Implications for Improved Control
title_sort key characteristics of residual malaria transmission in two districts in south-eastern tanzania—implications for improved control
topic Supplement Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079133/
https://www.ncbi.nlm.nih.gov/pubmed/33906218
http://dx.doi.org/10.1093/infdis/jiaa653
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