25
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Effectiveness of repellent delivered through village health volunteers on malaria incidence in villages in South-East Myanmar: a stepped-wedge cluster-randomised controlled trial protocol

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Background

          To combat emerging drug resistance in the Greater Mekong Sub-region (GMS) the World Health Organization and GMS countries have committed to eliminating malaria in the region by 2030. The overall approach includes providing universal access to diagnosis and treatment of malaria, and sustainable preventive measures, including vector control. Topical repellents are an intervention that can be used to target residual malaria transmission not covered by long lasting insecticide nets and indoor residual spraying. Although there is strong evidence that topical repellents protect against mosquito bites, evidence is not well established for the effectiveness of repellents distributed as part of malaria control activities in protecting against episodes of malaria. A common approach to deliver malaria services is to assign Village Health Volunteers (VHVs) to villages, particularly where limited or no services exist. The proposed trial aims to provide evidence for the effectiveness of repellent distributed through VHVs in reducing malaria.

          Methods

          The study is an open stepped-wedge cluster-randomised controlled trial randomised at the village level. Using this approach, repellent (N,N-diethyl-benzamide – 12% w/w, cream) is distributed by VHVs in villages sequentially throughout the malaria transmission season. Villages will be grouped into blocks, with blocks transitioned monthly from control (no repellent) to intervention states (to receive repellent) across 14 monthly intervals in random order). This follows a 4-week baseline period where all villages do not receive repellent. The primary endpoint is defined as the number of individuals positive for Plasmodium falciparum and Plasmodium vivax infections diagnosed by a rapid diagnostic test. Secondary endpoints include symptomatic malaria, Polymerase Chain Reaction (PCR)-detectable Plasmodium spp. infections, molecular markers of drug resistance and antibodies specific for Plasmodium spp. parasites.

          Discussion

          This study has been approved by relevant institutional ethics committees in Myanmar and Australia. Results will be disseminated through workshops, conferences and peer-reviewed publications. Findings will contribute to a better understanding of the optimal distribution mechanisms of repellent, context specific effectiveness and inform policy makers and implementers of malaria elimination programs in the GMS.

          Trial registration

          Australian and New Zealand Clinical Trials Registry ( ACTRN12616001434482). Retrospectively registered 14th October 2016.

          Electronic supplementary material

          The online version of this article (10.1186/s12879-018-3566-y) contains supplementary material, which is available to authorized users.

          Related collections

          Most cited references12

          • Record: found
          • Abstract: found
          • Article: not found

          Multiple populations of artemisinin-resistant Plasmodium falciparum in Cambodia

          We describe an analysis of genome variation in 825 Plasmodium falciparum samples from Asia and Africa that reveals an unusual pattern of parasite population structure at the epicentre of artemisinin resistance in western Cambodia. Within this relatively small geographical area we have discovered several distinct but apparently sympatric parasite subpopulations with extremely high levels of genetic differentiation. Of particular interest are three subpopulations, all associated with clinical resistance to artemisinin, which have skewed allele frequency spectra and remarkably high levels of haplotype homozygosity, indicative of founder effects and recent population expansion. We provide a catalogue of SNPs that show high levels of differentiation in the artemisinin-resistant subpopulations, including codon variants in various transporter proteins and DNA mismatch repair proteins. These data provide a population genetic framework for investigating the biological origins of artemisinin resistance and for defining molecular markers to assist its elimination.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Stepped wedge designs could reduce the required sample size in cluster randomized trials.

            The stepped wedge design is increasingly being used in cluster randomized trials (CRTs). However, there is not much information available about the design and analysis strategies for these kinds of trials. Approaches to sample size and power calculations have been provided, but a simple sample size formula is lacking. Therefore, our aim is to provide a sample size formula for cluster randomized stepped wedge designs. We derived a design effect (sample size correction factor) that can be used to estimate the required sample size for stepped wedge designs. Furthermore, we compared the required sample size for the stepped wedge design with a parallel group and analysis of covariance (ANCOVA) design. Our formula corrects for clustering as well as for the design. Apart from the cluster size and intracluster correlation, the design effect depends on choices of the number of steps, the number of baseline measurements, and the number of measurements between steps. The stepped wedge design requires a substantial smaller sample size than a parallel group and ANCOVA design. For CRTs, the stepped wedge design is far more efficient than the parallel group and ANCOVA design in terms of sample size. Copyright © 2013 Elsevier Inc. All rights reserved.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Stepped-wedge cluster randomised controlled trials: a generic framework including parallel and multiple-level designs

              Stepped-wedge cluster randomised trials (SW-CRTs) are being used with increasing frequency in health service evaluation. Conventionally, these studies are cross-sectional in design with equally spaced steps, with an equal number of clusters randomised at each step and data collected at each and every step. Here we introduce several variations on this design and consider implications for power. One modification we consider is the incomplete cross-sectional SW-CRT, where the number of clusters varies at each step or where at some steps, for example, implementation or transition periods, data are not collected. We show that the parallel CRT with staggered but balanced randomisation can be considered a special case of the incomplete SW-CRT. As too can the parallel CRT with baseline measures. And we extend these designs to allow for multiple layers of clustering, for example, wards within a hospital. Building on results for complete designs, power and detectable difference are derived using a Wald test and obtaining the variance–covariance matrix of the treatment effect assuming a generalised linear mixed model. These variations are illustrated by several real examples. We recommend that whilst the impact of transition periods on power is likely to be small, where they are a feature of the design they should be incorporated. We also show examples in which the power of a SW-CRT increases as the intra-cluster correlation (ICC) increases and demonstrate that the impact of the ICC is likely to be smaller in a SW-CRT compared with a parallel CRT, especially where there are multiple levels of clustering. Finally, through this unified framework, the efficiency of the SW-CRT and the parallel CRT can be compared.
                Bookmark

                Author and article information

                Contributors
                winhan.oo@burnet.edu.au
                julia.cutts@burnet.edu.au
                paul.agius@burnet.edu.au
                kyawzayaraung@burnetmyanmar.org
                poepoeaung@burnetmyanmar.org
                aungthi08@gmail.com
                nyinyizaw@burnetmyanmar.org
                htinkyaw.thu@savethechildren.org
                waiyanminhtay@burnetmyanmar.org
                ricardo.ataide@burnet.edu.au
                katherine.oflaherty@burnet.edu.au
                apyawn@gmail.com
                dr.aungpaing.soe2012@gmail.com
                beeson@burnet.edu.au
                brendan.crabb@burnet.edu.au
                naanki.pasricha@burnet.edu.au
                +613 8506 2310 , freya.fowkes@burnet.edu.au
                Journal
                BMC Infect Dis
                BMC Infect. Dis
                BMC Infectious Diseases
                BioMed Central (London )
                1471-2334
                14 December 2018
                14 December 2018
                2018
                : 18
                : 663
                Affiliations
                [1 ]ISNI 0000 0001 2224 8486, GRID grid.1056.2, Burnet Institute, ; Melbourne, Australia
                [2 ]Burnet Institute, Yangon, Myanmar
                [3 ]ISNI 0000 0004 1936 7857, GRID grid.1002.3, Department of Epidemiology and Preventive Medicine, , Monash University, ; Melbourne, Australia
                [4 ]ISNI 0000 0001 2342 0938, GRID grid.1018.8, Judith Lumley Centre, , La Trobe University, ; Melbourne, Australia
                [5 ]Department of Public Health, Myanmar Ministry of Health and Sport, Nay Pyi Taw, Myanmar
                [6 ]ISNI 0000 0001 2179 088X, GRID grid.1008.9, Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, , University of Melbourne, ; Melbourne, Australia
                [7 ]ISNI 0000 0001 2179 088X, GRID grid.1008.9, Department of Medicine, , University of Melbourne, ; Melbourne, Australia
                [8 ]ISNI 0000 0004 1936 7857, GRID grid.1002.3, Department of Microbiology and Central Clinical School, , Monash University, ; Melbourne, Australia
                Article
                3566
                10.1186/s12879-018-3566-y
                6295052
                30547749
                7511bf48-063d-4c3e-9022-65c31cf0e3bd
                © The Author(s). 2018

                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.

                History
                : 3 August 2017
                : 29 November 2018
                Funding
                Funded by: 3 MDG Fund
                Funded by: Burnet Institute (AU)
                Funded by: Victorian State Government Operational Infrastructure Support grant
                Categories
                Study Protocol
                Custom metadata
                © The Author(s) 2018

                Infectious disease & Microbiology
                malaria,repellent,mosquito,plasmodium
                Infectious disease & Microbiology
                malaria, repellent, mosquito, plasmodium

                Comments

                Comment on this article