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Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia

BACKGROUND: Conflicting results exist on the added benefit of combining long-lasting insecticidal nets (LLINs) with indoor residual spraying (IRS) to control malaria infection. The main study objective was to evaluate whether the combined use of LLINs and IRS with propoxur provides additional protec...

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Autores principales: Loha, Eskindir, Deressa, Wakgari, Gari, Taye, Balkew, Meshesha, Kenea, Oljira, Solomon, Tarekegn, Hailu, Alemayehu, Robberstad, Bjarne, Assegid, Meselech, Overgaard, Hans J., Lindtjørn, Bernt
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471954/
https://www.ncbi.nlm.nih.gov/pubmed/30999957
http://dx.doi.org/10.1186/s12936-019-2775-1
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author Loha, Eskindir
Deressa, Wakgari
Gari, Taye
Balkew, Meshesha
Kenea, Oljira
Solomon, Tarekegn
Hailu, Alemayehu
Robberstad, Bjarne
Assegid, Meselech
Overgaard, Hans J.
Lindtjørn, Bernt
author_facet Loha, Eskindir
Deressa, Wakgari
Gari, Taye
Balkew, Meshesha
Kenea, Oljira
Solomon, Tarekegn
Hailu, Alemayehu
Robberstad, Bjarne
Assegid, Meselech
Overgaard, Hans J.
Lindtjørn, Bernt
author_sort Loha, Eskindir
collection PubMed
description BACKGROUND: Conflicting results exist on the added benefit of combining long-lasting insecticidal nets (LLINs) with indoor residual spraying (IRS) to control malaria infection. The main study objective was to evaluate whether the combined use of LLINs and IRS with propoxur provides additional protection against Plasmodium falciparum and/or Plasmodium vivax among all age groups compared to LLINs or IRS alone. METHODS: This cluster-randomized, controlled trial was conducted in the Rift Valley area of Ethiopia from September 2014 to January 2017 (121 weeks); 44 villages were allocated to each of four study arms: LLIN + IRS, IRS, LLIN, and control. Each week, 6071 households with 34,548 persons were surveyed by active and passive case detection for clinical malaria. Primary endpoints were the incidence of clinical malaria and anaemia prevalence. RESULTS: During the study, 1183 malaria episodes were identified, of which 55.1% were P. falciparum and 25.3% were P. vivax, and 19.6% were mixed infections of P. falciparum and P. vivax. The overall malaria incidence was 16.5 per 1000 person-years of observation time (PYO), and similar in the four arms with 17.2 per 1000 PYO in the LLIN + IRS arm, 16.1 in LLIN, 17.0 in IRS, and 15.6 in the control arm. There was no significant difference in risk of anaemia among the trial arms. CONCLUSIONS: The clinical malaria incidence and anaemia prevalence were similar in the four study groups. In areas with low malaria incidence, using LLINs and IRS in combination or alone may not eliminate malaria. Complementary interventions that reduce residual malaria transmission should be explored in addition to LLINs and IRS to further reduce malaria transmission in such settings. Trial registration PACTR201411000882128 (08 September 2014) ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12936-019-2775-1) contains supplementary material, which is available to authorized users.
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spelling pubmed-64719542019-04-24 Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia Loha, Eskindir Deressa, Wakgari Gari, Taye Balkew, Meshesha Kenea, Oljira Solomon, Tarekegn Hailu, Alemayehu Robberstad, Bjarne Assegid, Meselech Overgaard, Hans J. Lindtjørn, Bernt Malar J Research BACKGROUND: Conflicting results exist on the added benefit of combining long-lasting insecticidal nets (LLINs) with indoor residual spraying (IRS) to control malaria infection. The main study objective was to evaluate whether the combined use of LLINs and IRS with propoxur provides additional protection against Plasmodium falciparum and/or Plasmodium vivax among all age groups compared to LLINs or IRS alone. METHODS: This cluster-randomized, controlled trial was conducted in the Rift Valley area of Ethiopia from September 2014 to January 2017 (121 weeks); 44 villages were allocated to each of four study arms: LLIN + IRS, IRS, LLIN, and control. Each week, 6071 households with 34,548 persons were surveyed by active and passive case detection for clinical malaria. Primary endpoints were the incidence of clinical malaria and anaemia prevalence. RESULTS: During the study, 1183 malaria episodes were identified, of which 55.1% were P. falciparum and 25.3% were P. vivax, and 19.6% were mixed infections of P. falciparum and P. vivax. The overall malaria incidence was 16.5 per 1000 person-years of observation time (PYO), and similar in the four arms with 17.2 per 1000 PYO in the LLIN + IRS arm, 16.1 in LLIN, 17.0 in IRS, and 15.6 in the control arm. There was no significant difference in risk of anaemia among the trial arms. CONCLUSIONS: The clinical malaria incidence and anaemia prevalence were similar in the four study groups. In areas with low malaria incidence, using LLINs and IRS in combination or alone may not eliminate malaria. Complementary interventions that reduce residual malaria transmission should be explored in addition to LLINs and IRS to further reduce malaria transmission in such settings. Trial registration PACTR201411000882128 (08 September 2014) ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12936-019-2775-1) contains supplementary material, which is available to authorized users. BioMed Central 2019-04-18 /pmc/articles/PMC6471954/ /pubmed/30999957 http://dx.doi.org/10.1186/s12936-019-2775-1 Text en © The Author(s) 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Loha, Eskindir
Deressa, Wakgari
Gari, Taye
Balkew, Meshesha
Kenea, Oljira
Solomon, Tarekegn
Hailu, Alemayehu
Robberstad, Bjarne
Assegid, Meselech
Overgaard, Hans J.
Lindtjørn, Bernt
Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title_full Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title_fullStr Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title_full_unstemmed Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title_short Long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in Ethiopia
title_sort long-lasting insecticidal nets and indoor residual spraying may not be sufficient to eliminate malaria in a low malaria incidence area: results from a cluster randomized controlled trial in ethiopia
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471954/
https://www.ncbi.nlm.nih.gov/pubmed/30999957
http://dx.doi.org/10.1186/s12936-019-2775-1
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