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Monroe A, Moore S, Okumu F, Kiware S, Lobo NF, Koenker H, Sherrard-Smith E, Gimnig J, Killeen GF. Correction: Methods and indicators for measuring patterns of human exposure to malaria vectors. Malar J 2023; 22:270. [PMID: 37705029 PMCID: PMC10500879 DOI: 10.1186/s12936-023-04676-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023] Open
Affiliation(s)
- April Monroe
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA.
- University of Basel, Basel, Switzerland.
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Sarah Moore
- University of Basel, Basel, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Samson Kiware
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Hannah Koenker
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - John Gimnig
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- School of Biological, Earth & Environmental Sciences and Environmental Research Institute, University College Cork, Cork, Republic of Ireland
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Eisele TP, Kleinschmidt I, Sarrassat S, terKuile F, Miller J, Chanda J, Silumbe K, Samuels A, Janssen J, Ogwang C, Bradley J, Orange E, Yukich J, Ashton R, Kyomuhangi I, Harris AF, Doumbia S, Toure M, Moumine M, Majambere S, Mburu MM, Mwaanga G, Simubali L, Simulundu E, Bennett A, Slutsker L, Muller G, Ochomo E, Gimnig J, Johnson PCD, Wagman J, Littrell M. Attractive targeted sugar bait phase III trials in Kenya, Mali, and Zambia. Trials 2022; 23:640. [PMID: 35945599 PMCID: PMC9361277 DOI: 10.1186/s13063-022-06555-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/16/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) target night-time indoor biting mosquitoes and effectively reduce malaria transmission in rural settings across Africa, but additional vector control tools are needed to interrupt transmission. Attractive targeted sugar baits (ATSBs) attract and kill mosquitoes, including those biting outdoors. Deployment of ATSBs incorporating the insecticide dinotefuran was associated with major reductions in mosquito density and longevity in Mali. The impact of this promising intervention on malaria transmission and morbidity now needs to be determined in a range of transmission settings. METHODS/DESIGN We will conduct three similar stand-alone, open-label, two-arm, cluster-randomized, controlled trials (cRCTs) in Mali, Kenya, and Zambia to determine the impact of ATSB + universal vector control versus universal vector control alone on clinical malaria. The trials will use a "fried-egg" design, with primary outcomes measured in the core area of each cluster to reduce spill-over effects. All household structures in the ATSB clusters will receive two ATSBs, but the impact will be measured in the core of clusters. Restricted randomization will be used. The primary outcome is clinical malaria incidence among children aged 5-14 years in Mali and 1-14 years in Kenya and Zambia. A key secondary outcome is malaria parasite prevalence across all ages. The trials will include 76 clusters (38 per arm) in Mali and 70 (35 per arm) in each of Kenya and Zambia. The trials are powered to detect a 30% reduction in clinical malaria, requiring a total of 3850 person-years of follow-up in Mali, 1260 person-years in Kenya, and 1610 person-years in Zambia. These sample sizes will be ascertained using two seasonal 8-month cohorts in Mali and two 6-month seasonal cohorts in Zambia. In Kenya, which has year-round transmission, four 6-month cohorts will be used (total 24 months of follow-up). The design allows for one interim analysis in Mali and Zambia and two in Kenya. DISCUSSION Strengths of the design include the use of multiple study sites with different transmission patterns and a range of vectors to improve external validity, a large number of clusters within each trial site, restricted randomization, between-cluster separation to minimize contamination between study arms, and an adaptive trial design. Noted threats to internal validity include open-label design, risk of contamination between study arms, risk of imbalance of covariates across study arms, variation in durability of ATSB stations, and potential disruption resulting from the COVID-19 pandemic. TRIAL REGISTRATION Zambia: ClinicalTrials.gov NCT04800055 . Registered on March 15, 2021 Mali: ClinicalTrials.gov NCT04149119 . Registered on November 4, 2019 Kenya: ClinicalTrials.gov NCT05219565 . Registered on February 2, 2022.
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Mitchell RM, Zhou Z, Sheth M, Sergent S, Frace M, Nayak V, Hu B, Gimnig J, Ter Kuile F, Lindblade K, Slutsker L, Hamel MJ, Desai M, Otieno K, Kariuki S, Vigfusson Y, Shi YP. Development of a new barcode-based, multiplex-PCR, next-generation-sequencing assay and data processing and analytical pipeline for multiplicity of infection detection of Plasmodium falciparum. Malar J 2021; 20:92. [PMID: 33593329 PMCID: PMC7885407 DOI: 10.1186/s12936-021-03624-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Simultaneous infection with multiple malaria parasite strains is common in high transmission areas. Quantifying the number of strains per host, or the multiplicity of infection (MOI), provides additional parasite indices for assessing transmission levels but it is challenging to measure accurately with current tools. This paper presents new laboratory and analytical methods for estimating the MOI of Plasmodium falciparum. METHODS Based on 24 single nucleotide polymorphisms (SNPs) previously identified as stable, unlinked targets across 12 of the 14 chromosomes within P. falciparum genome, three multiplex PCRs of short target regions and subsequent next generation sequencing (NGS) of the amplicons were developed. A bioinformatics pipeline including B4Screening pathway removed spurious amplicons to ensure consistent frequency calls at each SNP location, compiled amplicons by SNP site diversity, and performed algorithmic haplotype and strain reconstruction. The pipeline was validated by 108 samples generated from cultured-laboratory strain mixtures in different proportions and concentrations, with and without pre-amplification, and using whole blood and dried blood spots (DBS). The pipeline was applied to 273 smear-positive samples from surveys conducted in western Kenya, then providing results into StrainRecon Thresholding for Infection Multiplicity (STIM), a novel MOI estimator. RESULTS The 24 barcode SNPs were successfully identified uniformly across the 12 chromosomes of P. falciparum in a sample using the pipeline. Pre-amplification and parasite concentration, while non-linearly associated with SNP read depth, did not influence the SNP frequency calls. Based on consistent SNP frequency calls at targeted locations, the algorithmic strain reconstruction for each laboratory-mixed sample had 98.5% accuracy in dominant strains. STIM detected up to 5 strains in field samples from western Kenya and showed declining MOI over time (q < 0.02), from 4.32 strains per infected person in 1996 to 4.01, 3.56 and 3.35 in 2001, 2007 and 2012, and a reduction in the proportion of samples with 5 strains from 57% in 1996 to 18% in 2012. CONCLUSION The combined approach of new multiplex PCRs and NGS, the unique bioinformatics pipeline and STIM could identify 24 barcode SNPs of P. falciparum correctly and consistently. The methodology could be applied to field samples to reliably measure temporal changes in MOI.
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Affiliation(s)
- Rebecca M Mitchell
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
- Department of Computer Science, Emory University, Atlanta, USA
- School of Nursing, Emory University, Atlanta, USA
| | - Zhiyong Zhou
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mili Sheth
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Sheila Sergent
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Michael Frace
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Vishal Nayak
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - Bin Hu
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - John Gimnig
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | | | - Kim Lindblade
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mary J Hamel
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Meghna Desai
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Ymir Vigfusson
- Department of Computer Science, Emory University, Atlanta, USA.
| | - Ya Ping Shi
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA.
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Monroe A, Moore S, Okumu F, Kiware S, Lobo NF, Koenker H, Sherrard-Smith E, Gimnig J, Killeen GF. Correction to: Methods and indicators for measuring patterns of human exposure to malaria vectors. Malar J 2020; 19:243. [PMID: 32660476 PMCID: PMC7359248 DOI: 10.1186/s12936-020-03308-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Affiliation(s)
- April Monroe
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA. .,University of Basel, Basel, Switzerland. .,Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Sarah Moore
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Samson Kiware
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Hannah Koenker
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - John Gimnig
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.,School of Biological, Earth & Environmental Sciences and Environmental Research Institute, University College Cork, Cork, Republic of Ireland
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5
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Monroe A, Moore S, Okumu F, Kiware S, Lobo NF, Koenker H, Sherrard-Smith E, Gimnig J, Killeen GF. Methods and indicators for measuring patterns of human exposure to malaria vectors. Malar J 2020; 19:207. [PMID: 32546166 PMCID: PMC7296719 DOI: 10.1186/s12936-020-03271-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 05/29/2020] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Effective targeting and evaluation of interventions that protect against adult malaria vectors requires an understanding of how gaps in personal protection arise. An improved understanding of human and mosquito behaviour, and how they overlap in time and space, is critical to estimating the impact of insecticide-treated nets (ITNs) and determining when and where supplemental personal protection tools are needed. Methods for weighting estimates of human exposure to biting Anopheles mosquitoes according to where people spend their time were first developed over half a century ago. However, crude indoor and outdoor biting rates are still commonly interpreted as indicative of human-vector contact patterns without any adjustment for human behaviour or the personal protection effects of ITNs. MAIN TEXT A small number of human behavioural variables capturing the distribution of human populations indoors and outdoors, whether they are awake or asleep, and if and when they use an ITN over the course of the night, can enable a more accurate representation of human biting exposure patterns. However, to date no clear guidance is available on what data should be collected, what indicators should be reported, or how they should be calculated. This article presents an integrated perspective on relevant indicators of human-vector interactions, the critical entomological and human behavioural data elements required to quantify human-vector interactions, and recommendations for collecting and analysing such data. CONCLUSIONS If collected and used consistently, this information can contribute to an improved understanding of how malaria transmission persists in the context of current intervention tools, how exposure patterns may change as new vector control tools are introduced, and the potential impact and limitations of these tools. This article is intended to consolidate understanding around work on this topic to date and provide a consistent framework for building upon it. Additional work is needed to address remaining questions, including further development and validation of methods for entomological and human behavioural data collection and analysis.
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Affiliation(s)
- April Monroe
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA.
- University of Basel, Basel, Switzerland.
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Sarah Moore
- University of Basel, Basel, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Samson Kiware
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Hannah Koenker
- Johns Hopkins Center for Communication Programs, PMI VectorWorks Project, Baltimore, MD, USA
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - John Gimnig
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- School of Biological, Earth & Environmental Sciences and Environmental Research Institute, University College Cork, Cork, Republic of Ireland
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Kheang ST, Sovannaroth S, Barat LM, Dysoley L, Kapella BK, Po L, Nguon S, Gimnig J, Slot R, Samphornarann T, Meng SK, Dissanayake G, AlMossawi HJ, Longacre C, Kak N. Malaria elimination using the 1-3-7 approach: lessons from Sampov Loun, Cambodia. BMC Public Health 2020; 20:544. [PMID: 32321475 PMCID: PMC7178947 DOI: 10.1186/s12889-020-08634-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 04/01/2020] [Indexed: 11/17/2022] Open
Abstract
Background Cambodia has targeted malaria elimination within its territory by 2025 and is developing a model elimination package of strategies and interventions designed to achieve this goal. Methods Cambodia adopted a simplified 1-3-7 surveillance model in the Sampov Loun operational health district in western Cambodia beginning in July 2015. The 1-3-7 approach targets reporting of confirmed cases within one day, investigation of specific cases within three days, and targeted control measures to prevent further transmission within seven days. In Sampov Loun, response measures included reactive case detection (testing of co-travelers, household contacts and family members, and surrounding households with suspected malaria cases), and provision of health education, and insecticide-treated nets. Day 28 follow up microscopy was conducted for all confirmed P. falciparum and P. falciparum-mixed-species malaria cases to assess treatment efficacy. Results The number of confirmed malaria cases in the district fell from 519 in 2015 to 181 in 2017, and the annual parasite incidence (API) in the district fell from 3.21 per 1000 population to 1.06 per 1000 population. The last locally transmitted case of malaria in Sampov Loun was identified in March 2016. In response to the 408 index cases identified, 1377 contacts were screened, resulting in the identification of 14 positive cases. All positive cases occurred among index case co-travelers. Conclusion The experience of the 1-3-7 approach in Sampov Loun indicates that the basic essential malaria elimination package can be feasibly implemented at the operational district level to achieve the goal of malaria elimination in Cambodia and has provided essential information that has led to the refinement of this package.
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Affiliation(s)
| | | | - Lawrence M Barat
- President's Malaria Initiative/United States Agency for International Development, Washington, DC, USA
| | - Lek Dysoley
- National Malaria Control Program, Phnom Penh, Cambodia
| | - Bryan K Kapella
- President's Malaria Initiative/Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ly Po
- National Malaria Control Program, Phnom Penh, Cambodia
| | | | - John Gimnig
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Rida Slot
- President's Malaria Initiative/United States Agency for International Development, Phnom Penh, Cambodia
| | | | | | - Gunawardena Dissanayake
- President's Malaria Initiative/United States Agency for International Development, Phnom Penh, Cambodia
| | | | | | - Neeraj Kak
- University Research Co., LLC, Chevy Chase, MD, USA.
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Odero NA, Samuels AM, Odongo W, Abong'o B, Gimnig J, Otieno K, Odero C, Obor D, Ombok M, Were V, Sang T, Hamel MJ, Kachur SP, Slutsker L, Lindblade KA, Kariuki S, Desai M. Community-based intermittent mass testing and treatment for malaria in an area of high transmission intensity, western Kenya: development of study site infrastructure and lessons learned. Malar J 2019; 18:255. [PMID: 31357997 PMCID: PMC6664589 DOI: 10.1186/s12936-019-2896-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/23/2019] [Indexed: 01/06/2023] Open
Abstract
Background Malaria transmission is high in western Kenya and the asymptomatic infected population plays a significant role in driving the transmission. Mathematical modelling and simulation programs suggest that interventions targeting asymptomatic infections through mass testing and treatment (MTaT) or mass drug administration (MDA) have the potential to reduce malaria transmission when combined with existing interventions. Objective This paper describes the study site, capacity development efforts required, and lessons learned for implementing a multi-year community-based cluster-randomized controlled trial to evaluate the impact of MTaT for malaria transmission reduction in an area of high transmission in western Kenya. Methods The study partnered with Kenya’s Ministry of Health (MOH) and other organizations on community sensitization and engagement to mobilize, train and deploy community health volunteers (CHVs) to deliver MTaT in the community. Within the health facilities, the study availed staff, medical and laboratory supplies and strengthened health information management system to monitor progress and evaluate impact of intervention. Results More than 80 Kenya MOH CHVs, 13 clinical officers, field workers, data and logistical staff were trained to carry out MTaT three times a year for 2 years in a population of approximately 90,000 individuals. A supply chain management was adapted to meet daily demands for large volumes of commodities despite the limitation of few MOH facilities having ideal storage conditions. Modern technology was adapted more to meet the needs of the high daily volume of collected data. Conclusions In resource-constrained settings, large interventions require capacity building and logistical planning. This study found that investing in relationships with the communities, local governments, and other partners, and identifying and equipping the appropriate staff with the skills and technology to perform tasks are important factors for success in delivering an intervention like MTaT.
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Affiliation(s)
- Norbert Awino Odero
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya.
| | - Aaron M Samuels
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Wycliffe Odongo
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Bernard Abong'o
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - John Gimnig
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Kephas Otieno
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Christopher Odero
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - David Obor
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Maurice Ombok
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Vincent Were
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Tony Sang
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Mary J Hamel
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - S Patrick Kachur
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | | | - Kim A Lindblade
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Simon Kariuki
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Meghna Desai
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
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Khagayi S, Desai M, Amek N, Were V, Onyango ED, Odero C, Otieno K, Bigogo G, Munga S, Odhiambo F, Hamel MJ, Kariuki S, Samuels AM, Slutsker L, Gimnig J, Vounatsou P. Modelling the relationship between malaria prevalence as a measure of transmission and mortality across age groups. Malar J 2019; 18:247. [PMID: 31337411 PMCID: PMC6651924 DOI: 10.1186/s12936-019-2869-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/05/2019] [Indexed: 11/24/2022] Open
Abstract
Background Parasite prevalence has been used widely as a measure of malaria transmission, especially in malaria endemic areas. However, its contribution and relationship to malaria mortality across different age groups has not been well investigated. Previous studies in a health and demographic surveillance systems (HDSS) platform in western Kenya quantified the contribution of incidence and entomological inoculation rates (EIR) to mortality. The study assessed the relationship between outcomes of malaria parasitaemia surveys and mortality across age groups. Methods Parasitological data from annual cross-sectional surveys from the Kisumu HDSS between 2007 and 2015 were used to determine malaria parasite prevalence (PP) and clinical malaria (parasites plus reported fever within 24 h or temperature above 37.5 °C). Household surveys and verbal autopsy (VA) were used to obtain data on all-cause and malaria-specific mortality. Bayesian negative binomial geo-statistical regression models were used to investigate the association of PP/clinical malaria with mortality across different age groups. Estimates based on yearly data were compared with those from aggregated data over 4 to 5-year periods, which is the typical period that mortality data are available from national demographic and health surveys. Results Using 5-year aggregated data, associations were established between parasite prevalence and malaria-specific mortality in the whole population (RRmalaria = 1.66; 95% Bayesian Credible Intervals: 1.07–2.54) and children 1–4 years (RRmalaria = 2.29; 1.17–4.29). While clinical malaria was associated with both all-cause and malaria-specific mortality in combined ages (RRall-cause = 1.32; 1.01–1.74); (RRmalaria = 2.50; 1.27–4.81), children 1–4 years (RRall-cause = 1.89; 1.00–3.51); (RRmalaria = 3.37; 1.23–8.93) and in older children 5–14 years (RRall-cause = 3.94; 1.34–11.10); (RRmalaria = 7.56; 1.20–39.54), no association was found among neonates, adults (15–59 years) and the elderly (60+ years). Distance to health facilities, socioeconomic status, elevation and survey year were important factors for all-cause and malaria-specific mortality. Conclusion Malaria parasitaemia from cross-sectional surveys was associated with mortality across age groups over 4 to 5 year periods with clinical malaria more strongly associated with mortality than parasite prevalence. This effect was stronger in children 5–14 years compared to other age-groups. Further analyses of data from other HDSS sites or similar platforms would be useful in investigating the relationship between malaria and mortality across different endemicity levels. Electronic supplementary material The online version of this article (10.1186/s12936-019-2869-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sammy Khagayi
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Nyaguara Amek
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Vincent Were
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Eric Donald Onyango
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Christopher Odero
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Kephas Otieno
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Stephen Munga
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Frank Odhiambo
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Mary J Hamel
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute-Center for Global Health Research, Kisumu, Kenya
| | - Aaron M Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Laurence Slutsker
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - John Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.,Centers for Disease Control and Prevention, Kisumu, Kenya
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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Abong'o B, Yu X, Donnelly MJ, Geier M, Gibson G, Gimnig J, Ter Kuile F, Lobo NF, Ochomo E, Munga S, Ombok M, Samuels A, Torr SJ, Hawkes FM. Host Decoy Trap (HDT) with cattle odour is highly effective for collection of exophagic malaria vectors. Parasit Vectors 2018; 11:533. [PMID: 30318015 PMCID: PMC6191991 DOI: 10.1186/s13071-018-3099-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As currently implemented, malaria vector surveillance in sub-Saharan Africa targets endophagic and endophilic mosquitoes, leaving exophagic (outdoor blood-feeding) mosquitoes underrepresented. We evaluated the recently developed host decoy trap (HDT) and compared it to the gold standard, human landing catch (HLC), in a 3 × 3 Latin square study design outdoors in western Kenya. HLCs are considered to represent the natural range of Anopheles biting-behaviour compared to other sampling tools, and therefore, in principle, provide the most reliable profile of the biting population transmitting malaria. The HDT incorporates the main host stimuli that attract blood-meal seeking mosquitoes and can be baited with the odours of live hosts. RESULTS Numbers and species diversity of trapped mosquitoes varied significantly between HLCs and HDTs baited with human (HDT-H) or cattle (HDT-C) odour, revealing important differences in behaviour of Anopheles species. In the main study in Kisian, the HDT-C collected a nightly mean of 43.2 (95% CI: 26.7-69.8) Anopheles, compared to 5.8 (95% CI: 4.1-8.2) in HLC, while HDT-H collected 0.97 (95% CI: 0.4-2.1), significantly fewer than the HLC. Significantly higher proportions of An. arabiensis were caught in HDT-Cs (0.94 ± 0.01; SE) and HDT-Hs (0.76 ± 0.09; SE) than in HLCs (0.45 ± 0.05; SE) per trapping night. The proportion of An. gambiae (s.s.) was highest in HLC (0.55 ± 0.05; SE) followed by HDT-H (0.20 ± 0.09; SE) and least in HDT-C (0.06 ± 0.01; SE). An unbaited HDT placed beside locales where cattle are usually corralled overnight caught mostly An. arabiensis with proportions of 0.97 ± 0.02 and 0.80 ± 0.2 relative to the total anopheline catch in the presence and absence of cattle, respectively. A mean of 10.4 (95% CI: 2.0-55.0) Anopheles/night were trapped near cattle, compared to 0.4 (95% CI: 0.1-1.7) in unbaited HDT away from hosts. CONCLUSIONS The capability of HDTs to combine host odours, heat and visual stimuli to simulate a host provides the basis of a system to sample human- and cattle-biting mosquitoes. HDT-C is particularly effective for collecting An. arabiensis outdoors. The HDT offers the prospect of a system to monitor and potentially control An. arabiensis and other outdoor-biting mosquitoes more effectively.
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Affiliation(s)
- Bernard Abong'o
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya. .,Abt Associates Inc. PMI-VectorLink Kenya, Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya.
| | - Xiaoyu Yu
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - Gabriella Gibson
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Feiko Ter Kuile
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Neil F Lobo
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Maurice Ombok
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Aaron Samuels
- Centers for Disease Control and Prevention, Kisian Campus, Off Busia Road, P O Box 1578, Kisumu, 40100, Kenya
| | - Stephen J Torr
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Frances M Hawkes
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK
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10
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Amek NO, Van Eijk A, Lindblade KA, Hamel M, Bayoh N, Gimnig J, Laserson KF, Slutsker L, Smith T, Vounatsou P. Infant and child mortality in relation to malaria transmission in KEMRI/CDC HDSS, Western Kenya: validation of verbal autopsy. Malar J 2018; 17:37. [PMID: 29347942 PMCID: PMC5774157 DOI: 10.1186/s12936-018-2184-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 01/10/2018] [Indexed: 12/02/2022] Open
Abstract
Background Malaria transmission reduction is a goal of many malaria control programmes. Little is known of how much mortality can be reduced by specific reductions in transmission. Verbal autopsy (VA) is widely used for estimating malaria specific mortality rates, but does not reliably distinguish malaria from other febrile illnesses. Overall malaria attributable mortality includes both direct and indirect deaths. It is unclear what proportion of the deaths averted by reducing malaria transmission are classified as malaria in VA. Methods Both all-cause, and cause-specific mortality reported by VA for children under 5 years of age, were assembled from the KEMRI/CDC health and demographic surveillance system in Siaya county, rural Western Kenya for the years 2002–2004. These were linked to household-specific estimates of the Plasmodium falciparum entomological inoculation rate (EIR) based on high resolution spatio-temporal geostatistical modelling of entomological data. All-cause and malaria specific mortality (by VA), were analysed in relation to EIR, insecticide-treated net use (ITN), socioeconomic status (SES) and parameters describing space–time correlation. Time at risk for each child was analysed using Bayesian geostatistical Cox proportional hazard models, with time-dependent covariates. The outputs were used to estimate the diagnostic performance of VA in measuring mortality that can be attributed to malaria exposure. Results The overall under-five mortality rate was 80 per 1000 person-years during the study period. Eighty-one percent of the total deaths were assigned causes of death by VA, with malaria assigned as the main cause of death except in the neonatal period. Although no trend was observed in malaria-specific mortality assessed by VA, ITN use was associated with reduced all-cause mortality in infants (hazard ratio 0.15, 95% CI 0.02, 0.63) and the EIR was strongly associated with both all-cause and malaria-specific mortality. 48.2% of the deaths could be attributed to malaria by analysing the exposure–response relationship, though only 20.5% of VAs assigned malaria as the cause and the sensitivity of VAs was estimated to be only 26%. Although VAs assigned some deaths to malaria even in areas where there was estimated to be no exposure, the specificity of the VAs was estimated to be 85%. Conclusion Interventions that reduce P. falciparum transmission intensity will not only significantly reduce malaria-diagnosed mortality, but also mortality assigned to other causes in under-5 year old children in endemic areas. In this setting, the VA tool based on clinician review substantially underestimates the number of deaths that could be averted by reducing malaria exposure in childhood, but has a reasonably high specificity. This suggests that malaria transmission-reducing interventions such as ITNs can potentially reduce overall child mortality by as much as twice the total direct malaria burden estimated from VAs. Electronic supplementary material The online version of this article (10.1186/s12936-018-2184-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nyaguara O Amek
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya. .,Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland.
| | - Annemieke Van Eijk
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya
| | - Kim A Lindblade
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Mary Hamel
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Nabie Bayoh
- Kenya Medical Research Institute, Centre for Global Health Research, P.O. Box 1578, Kisumu, Kenya
| | - John Gimnig
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Kayla F Laserson
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Laurence Slutsker
- Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA, 30301, USA
| | - Thomas Smith
- Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Socinstr. 57, P.O. Box, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, P.O. Box, 4003, Basel, Switzerland
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11
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Samuels AM, Awino N, Odongo W, Abong'o B, Gimnig J, Otieno K, Shi YP, Were V, Allen DR, Were F, Sang T, Obor D, Williamson J, Hamel MJ, Patrick Kachur S, Slutsker L, Lindblade KA, Kariuki S, Desai M. Community-based intermittent mass testing and treatment for malaria in an area of high transmission intensity, western Kenya: study design and methodology for a cluster randomized controlled trial. Malar J 2017; 16:240. [PMID: 28592250 PMCID: PMC5463392 DOI: 10.1186/s12936-017-1883-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 05/29/2017] [Indexed: 01/13/2023] Open
Abstract
Most human Plasmodium infections in western Kenya are asymptomatic and are believed to contribute importantly to malaria transmission. Elimination of asymptomatic infections requires active treatment approaches, such as mass testing and treatment (MTaT) or mass drug administration (MDA), as infected persons do not seek care for their infection. Evaluations of community-based approaches that are designed to reduce malaria transmission require careful attention to study design to ensure that important effects can be measured accurately. This manuscript describes the study design and methodology of a cluster-randomized controlled trial to evaluate a MTaT approach for malaria transmission reduction in an area of high malaria transmission. Ten health facilities in western Kenya were purposively selected for inclusion. The communities within 3 km of each health facility were divided into three clusters of approximately equal population size. Two clusters around each health facility were randomly assigned to the control arm, and one to the intervention arm. Three times per year for 2 years, after the long and short rains, and again before the long rains, teams of community health volunteers visited every household within the intervention arm, tested all consenting individuals with malaria rapid diagnostic tests, and treated all positive individuals with an effective anti-malarial. The effect of mass testing and treatment on malaria transmission was measured through population-based longitudinal cohorts, outpatient visits for clinical malaria, periodic population-based cross-sectional surveys, and entomological indices.
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Affiliation(s)
- Aaron M Samuels
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA. .,Centers for Disease Control and Prevention, Kisian Campus, Off Busia Road, P O Box 1578, Kisumu, 40100, Kenya.
| | - Nobert Awino
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Wycliffe Odongo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Benard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ya Ping Shi
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Denise Roth Allen
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Florence Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Tony Sang
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - David Obor
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Williamson
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - S Patrick Kachur
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kim A Lindblade
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Meghna Desai
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
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12
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Mtove G, Mugasa JP, Messenger LA, Malima RC, Mangesho P, Magogo F, Plucinski M, Hashimu R, Matowo J, Shepard D, Batengana B, Cook J, Emidi B, Halasa Y, Kaaya R, Kihombo A, Lindblade KA, Makenga G, Mpangala R, Mwambuli A, Mzava R, Mziray A, Olang G, Oxborough RM, Seif M, Sambu E, Samuels A, Sudi W, Thomas J, Weston S, Alilio M, Binkin N, Gimnig J, Kleinschmidt I, McElroy P, Moulton LH, Norris L, Ruebush T, Venkatesan M, Rowland M, Mosha FW, Kisinza WN. Erratum to: The effectiveness of non-pyrethroid insecticide-treated durable wall lining to control malaria in rural Tanzania: study protocol for a two-armed cluster randomized trial. BMC Public Health 2016; 16:1195. [PMID: 27887607 PMCID: PMC5123290 DOI: 10.1186/s12889-016-3856-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 11/12/2022] Open
Affiliation(s)
- George Mtove
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
| | - Joseph P Mugasa
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Louisa A Messenger
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert C Malima
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Peter Mangesho
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Franklin Magogo
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Mateusz Plucinski
- US President's Malaria Initiative, Atlanta, GA, USA.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ramadhan Hashimu
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | | | - Donald Shepard
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Bernard Batengana
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Jackie Cook
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Basiliana Emidi
- Kilimanjaro Christian Medical College, Moshi, Tanzania.,National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Yara Halasa
- Brandeis University, Heller School, Waltham, Massachusetts, USA
| | - Robert Kaaya
- Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Aggrey Kihombo
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Kimberly A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Geofrey Makenga
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Robert Mpangala
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Abraham Mwambuli
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Ruth Mzava
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Abubakary Mziray
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - George Olang
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | | | - Mohammed Seif
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Edward Sambu
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Aaron Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Wema Sudi
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - John Thomas
- Phoenix Ordinary LLC, Bridgewater, New Jersey, USA
| | - Sophie Weston
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Martin Alilio
- President's Malaria Initiative, United States Agency for International Development, Washington, DC, USA
| | - Nancy Binkin
- Translating Research into Action Project (TRAction) University Research Co., LLC, Bethesda, Maryland, USA
| | - John Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Immo Kleinschmidt
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Peter McElroy
- US President's Malaria Initiative, Atlanta, GA, USA.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lawrence H Moulton
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Laura Norris
- President's Malaria Initiative, United States Agency for International Development, Washington, DC, USA
| | - Trenton Ruebush
- Translating Research into Action Project (TRAction) University Research Co., LLC, Bethesda, Maryland, USA
| | - Meera Venkatesan
- President's Malaria Initiative, United States Agency for International Development, Washington, DC, USA
| | - Mark Rowland
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - William N Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
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13
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Smit MR, Ochomo E, Aljayyoussi G, Kwambai T, Abong'o B, Bayoh N, Gimnig J, Samuels A, Desai M, Phillips-Howard PA, Kariuki S, Wang D, Ward S, Ter Kuile FO. Efficacy and Safety of High-Dose Ivermectin for Reducing Malaria Transmission (IVERMAL): Protocol for a Double-Blind, Randomized, Placebo-Controlled, Dose-Finding Trial in Western Kenya. JMIR Res Protoc 2016; 5:e213. [PMID: 27856406 PMCID: PMC5133431 DOI: 10.2196/resprot.6617] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Innovative approaches are needed to complement existing tools for malaria elimination. Ivermectin is a broad spectrum antiparasitic endectocide clinically used for onchocerciasis and lymphatic filariasis control at single doses of 150 to 200 mcg/kg. It also shortens the lifespan of mosquitoes that feed on individuals recently treated with ivermectin. However, the effect after a 150 to 200 mcg/kg oral dose is short-lived (6 to 11 days). Modeling suggests higher doses, which prolong the mosquitocidal effects, are needed to make a significant contribution to malaria elimination. Ivermectin has a wide therapeutic index and previous studies have shown doses up to 2000 mcg/kg (ie, 10 times the US Food and Drug Administration approved dose) are well tolerated and safe; the highest dose used for onchocerciasis is a single dose of 800 mcg/kg. OBJECTIVE The aim of this study is to determine the safety, tolerability, and efficacy of ivermectin doses of 0, 300, and 600 mcg/kg/day for 3 days, when provided with a standard 3-day course of the antimalarial dihydroartemisinin-piperaquine (DP), on mosquito survival. METHODS This is a double-blind, randomized, placebo-controlled, parallel-group, 3-arm, dose-finding trial in adults with uncomplicated malaria. Monte Carlo simulations based on pharmacokinetic modeling were performed to determine the optimum dosing regimens to be tested. Modeling showed that a 3-day regimen of 600 mcg/kg/day achieved similar median (5 to 95 percentiles) maximum drug concentrations (Cmax) of ivermectin to a single of dose of 800 mcg/kg, while increasing the median time above the lethal concentration 50% (LC50, 16 ng/mL) from 1.9 days (1.0 to 5.7) to 6.8 (3.8 to 13.4) days. The 300 mcg/kg/day dose was chosen at 50% of the higher dose to allow evaluation of the dose response. Mosquito survival will be assessed daily up to 28 days in laboratory-reared Anopheles gambiae s.s. populations fed on patients' blood taken at days 0, 2 (Cmax), 7 (primary outcome), 10, 14, 21, and 28 after the start of treatment. Safety outcomes include QT-prolongation and mydriasis. The trial will be conducted in 6 health facilities in western Kenya and requires a sample size of 141 participants (47 per arm). Sub-studies include (1) rich pharmacokinetics and (2) direct skin versus membrane feeding assays. RESULTS Recruitment started July 20, 2015. Data collection was completed July 2, 2016. Unblinding and analysis will commence once the database has been completed, cleaned, and locked. CONCLUSIONS High-dose ivermectin, if found to be safe and well tolerated, might offer a promising new tool for malaria elimination.
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Affiliation(s)
- Menno R Smit
- Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | | | - Titus Kwambai
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya.,Kisumu County, Kenya Ministry of Health (MoH), Kisumu, Kenya
| | - Bernard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Nabie Bayoh
- Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Aaron Samuels
- Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Meghna Desai
- Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | | | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Duolao Wang
- Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | - Steve Ward
- Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | - Feiko O Ter Kuile
- Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
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14
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Mtove G, Mugasa JP, Messenger LA, Malima RC, Mangesho P, Magogo F, Plucinski M, Hashimu R, Matowo J, Shepard D, Batengana B, Cook J, Emidi B, Halasa Y, Kaaya R, Kihombo A, Lindblade KA, Makenga G, Mpangala R, Mwambuli A, Mzava R, Mziray A, Olang G, Oxborough RM, Seif M, Sambu E, Samuels A, Sudi W, Thomas J, Weston S, Alilio M, Binkin N, Gimnig J, Kleinschmidt I, McElroy P, Moulton LH, Norris L, Ruebush T, Venkatesan M, Rowland M, Mosha FW, Kisinza WN. The effectiveness of non-pyrethroid insecticide-treated durable wall lining to control malaria in rural Tanzania: study protocol for a two-armed cluster randomized trial. BMC Public Health 2016; 16:633. [PMID: 27456339 PMCID: PMC4960851 DOI: 10.1186/s12889-016-3287-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 07/09/2016] [Indexed: 11/16/2022] Open
Abstract
Background Despite considerable reductions in malaria achieved by scaling-up long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), maintaining sustained community protection remains operationally challenging. Increasing insecticide resistance also threatens to jeopardize the future of both strategies. Non-pyrethroid insecticidetreated wall lining (ITWL) may represent an alternate or complementary control method and a potential tool to manage insecticide resistance. To date no study has demonstrated whether ITWL can reduce malaria transmission nor provide additional protection beyond the current best practice of universal coverage (UC) of LLINs and prompt case management. Methods/design A two-arm cluster randomized controlled trial will be conducted in rural Tanzania to assess whether non-pyrethroid ITWL and UC of LLINs provide added protection against malaria infection in children, compared to UC of LLINs alone. Stratified randomization based on malaria prevalence will be used to select 22 village clusters per arm. All 44 clusters will receive LLINs and half will also have ITWL installed on interior house walls. Study children, aged 6 months to 11 years old, will be enrolled from each cluster and followed monthly to estimate cumulative incidence of malaria parasitaemia (primary endpoint), time to first malaria episode and prevalence of anaemia before and after intervention. Entomological inoculation rate will be estimated using indoor CDC light traps and outdoor tent traps followed by detection of Anopheles gambiae species, sporozoite infection, insecticide resistance and blood meal source. ITWL bioefficacy and durability will be monitored using WHO cone bioassays and household surveys, respectively. Social and cultural factors influencing community and household ITWL acceptability will be explored through focus-group discussions and in-depth interviews. Cost-effectiveness, compared between study arms, will be estimated per malaria case averted. Discussion This protocol describes the large-scale evaluation of a novel vector control product, designed to overcome some of the known limitations of existing methods. If ITWL is proven to be effective and durable under field conditions, it may warrant consideration for programmatic implementation, particularly in areas with long transmission seasons and where pyrethroid-resistant vectors predominate. Trial findings will provide crucial information for policy makers in Tanzania and other malaria-endemic countries to guide resource allocations for future control efforts. Trial registration NCT02533336 registered on 13 July 2014.
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Affiliation(s)
- George Mtove
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
| | - Joseph P Mugasa
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Louisa A Messenger
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert C Malima
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Peter Mangesho
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Franklin Magogo
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Mateusz Plucinski
- US President's Malaria Initiative, Atlanta, GA, USA.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ramadhan Hashimu
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | | | - Donald Shepard
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Bernard Batengana
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Jackie Cook
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Basiliana Emidi
- Kilimanjaro Christian Medical College, Moshi, Tanzania.,National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Yara Halasa
- Brandeis University, Heller School, Waltham, Massachusetts, USA
| | - Robert Kaaya
- Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Aggrey Kihombo
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Kimberly A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Geofrey Makenga
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Robert Mpangala
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Abraham Mwambuli
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Ruth Mzava
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Abubakary Mziray
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - George Olang
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | | | - Mohammed Seif
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Edward Sambu
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - Aaron Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Wema Sudi
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
| | - John Thomas
- Phoenix Ordinary LLC, Bridgewater, New Jersey, USA
| | - Sophie Weston
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Martin Alilio
- President's Malaria Initiative, United States Agency for International Development, Washington DC, USA
| | - Nancy Binkin
- Translating Research into Action Project (TRAction) University Research Co., LLC, Bethesda, Maryland, USA
| | - John Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Immo Kleinschmidt
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Peter McElroy
- US President's Malaria Initiative, Atlanta, GA, USA.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lawrence H Moulton
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Laura Norris
- President's Malaria Initiative, United States Agency for International Development, Washington DC, USA
| | - Trenton Ruebush
- Translating Research into Action Project (TRAction) University Research Co., LLC, Bethesda, Maryland, USA
| | - Meera Venkatesan
- President's Malaria Initiative, United States Agency for International Development, Washington DC, USA
| | - Mark Rowland
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - William N Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania
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15
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Hemingway J, Ranson H, Magill A, Kolaczinski J, Fornadel C, Gimnig J, Coetzee M, Simard F, Roch DK, Hinzoumbe CK, Pickett J, Schellenberg D, Gething P, Hoppé M, Hamon N. Averting a malaria disaster: will insecticide resistance derail malaria control? Lancet 2016; 387:1785-8. [PMID: 26880124 PMCID: PMC6215693 DOI: 10.1016/s0140-6736(15)00417-1] [Citation(s) in RCA: 274] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
World Malaria Day 2015 highlighted the progress made in the development of new methods of prevention (vaccines and insecticides) and treatment (single dose drugs) of the disease. However, increasing drug and insecticide resistance threatens the successes made with existing methods. Insecticide resistance has decreased the efficacy of the most commonly used insecticide class of pyrethroids. This decreased efficacy has increased mosquito survival, which is a prelude to rising incidence of malaria and fatalities. Despite intensive research efforts, new insecticides will not reach the market for at least 5 years. Elimination of malaria is not possible without effective mosquito control. Therefore, to combat the threat of resistance, key stakeholders need to rapidly embrace a multifaceted approach including a reduction in the cost of bringing new resistance management methods to market and the streamlining of associated development, policy, and implementation pathways to counter this looming public health catastrophe.
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Affiliation(s)
| | - Hilary Ranson
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Alan Magill
- Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Jan Kolaczinski
- The Global Fund to Fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland
| | - Christen Fornadel
- President's Malaria Initiative, US Agency for International Development, Washington, DC, USA
| | - John Gimnig
- Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, GA, USA
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Frederic Simard
- Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle (MIVEGEC), Université de Montpellier, Institut de Recherche pour le Développement, Montpellier, France
| | | | | | | | | | - Peter Gething
- London School of Hygiene & Tropical Medicine, London, UK
| | - Mark Hoppé
- Insecticide Resistance Action Committee, Crop Life International AISBL, Brussels, Belgium
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16
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Ochomo E, Subramaniam K, Kemei B, Rippon E, Bayoh NM, Kamau L, Atieli F, Vulule JM, Ouma C, Gimnig J, Donnelly MJ, Mbogo C. Presence of the knockdown resistance mutation, Vgsc-1014F in Anopheles gambiae and An. arabiensis in western Kenya. Parasit Vectors 2015; 8:616. [PMID: 26626424 PMCID: PMC4666190 DOI: 10.1186/s13071-015-1223-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 11/23/2015] [Indexed: 11/25/2022] Open
Abstract
Introduction The voltage gated sodium channel mutation Vgsc-1014S (kdr-east) was first reported in Kenya in 2000 and has since been observed to occur at high frequencies in the local Anopheles gambiae s.s. population. The mutation Vgsc-1014F has never been reported from An. gambiae Complex complex mosquitoes in Kenya. Findings Molecularly confirmed An. gambiae s.s. (hereafter An. gambiae) and An. arabiensis collected from 4 different parts of western Kenya were genotyped for kdr from 2011 to 2013. Vgsc-1014F was observed to have emerged, apparently, simultaneously in both An. gambiae and An. arabiensis in 2012. A portion of the samples were submitted for sequencing in order to confirm the Vgsc-1014F genotyping results. The resulting sequence data were deposited in GenBank (Accession numbers: KR867642-KR867651, KT758295-KT758303). A single Vgsc-1014F haplotype was observed suggesting, a common origin in both species. Conclusion This is the first report of Vgsc-1014F in Kenya. Based on our samples, the mutation is present in low frequencies in both An. gambiae and An. arabiensis. It is important that we start monitoring relative frequencies of the two kdr genes so that we can determine their relative importance in an area of high insecticide treated net ownership.
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Affiliation(s)
- Eric Ochomo
- School of Public Health and Community Development, Maseno University, Maseno, Kenya. .,Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578, Kisumu, 40100, Kenya.
| | | | - Brigid Kemei
- Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578, Kisumu, 40100, Kenya.
| | - Emily Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Nabie M Bayoh
- Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578, Kisumu, 40100, Kenya.
| | - Luna Kamau
- Centre for Biotechnology and Research Development, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Francis Atieli
- Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578, Kisumu, 40100, Kenya.
| | - John M Vulule
- Centre for Global Health Research, Kenya Medical Research Institute, P. O. Box 1578, Kisumu, 40100, Kenya.
| | - Collins Ouma
- School of Public Health and Community Development, Maseno University, Maseno, Kenya. .,Health Challenges and Systems, African Population and Health Research Centre, Nairobi, Kenya.
| | - John Gimnig
- Centers of Disease Control and Prevention, Atlanta, USA.
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK. .,Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, UK.
| | - Charles Mbogo
- Kenya Medical Research Institute, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya. .,Malaria Public Health Department, KEMRI-Wellcome Trust Research Program, Nairobi, Kenya.
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17
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Vanden Eng JL, Chan A, Abílio AP, Wolkon A, Ponce de Leon G, Gimnig J, Morgan J. Correction: Bed Net Durability Assessments: Exploring a Composite Measure of Net Damage. PLoS One 2015; 10:e0133105. [PMID: 26171973 PMCID: PMC4501801 DOI: 10.1371/journal.pone.0133105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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18
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Chanda E, Mzilahowa T, Chipwanya J, Mulenga S, Ali D, Troell P, Dodoli W, Govere JM, Gimnig J. Preventing malaria transmission by indoor residual spraying in Malawi: grappling with the challenge of uncertain sustainability. Malar J 2015; 14:254. [PMID: 26104657 PMCID: PMC4477419 DOI: 10.1186/s12936-015-0759-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/03/2015] [Indexed: 12/03/2022] Open
Abstract
Background In the past decade, there has been rapid scale-up of insecticide-based malaria vector control in the context of integrated vector management (IVM) according to World Health Organization recommendations. Endemic countries have deployed indoor residual spraying (IRS) and long-lasting insecticidal nets as hallmark vector control interventions. This paper discusses the successes and continued challenges and the way forward for the IRS programme in Malawi. Case description The National Malaria Control Programme in Malawi, with its efforts to implement an integrated approach to malaria vector control, was the ‘case’ for this study. Information sources included all available data and accessible archived documentary records on IRS in Malawi. A methodical assessment of published and unpublished documents was conducted via a literature search of online electronic databases. Discussion Malawi has implemented IRS as the main malaria transmission-reducing intervention. However, pyrethroid and carbamate resistance in malaria vectors has been detected extensively across the country and has adversely affected the IRS programme. Additionally, IRS activities have been characterized by substantial inherent logistical and technical challenges culminating into missed targets. As a consequence, programmatic IRS operations have been scaled down from seven districts in 2010 to only one district in 2014. The future of the IRS programme in Malawi is uncertain due to limited funding, high cost of alternative insecticides and technical resource challenges being experienced in the country. Conclusions The availability of a long-lasting formulation of the organophosphate pirimiphos-methyl makes the re-introduction of IRS a possibility and may be a useful approach for the management of pyrethroid resistance. Implementing the IVM strategy, advocating for sustainable domestic funding, including developing an insecticide resistance monitoring and management plan and vector surveillance guidelines will be pivotal in steering entomologic monitoring and future vector control activities in Malawi.
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Affiliation(s)
| | | | - John Chipwanya
- Ministry of Health, National Malaria Control Programme, Lilongwe, Malawi.
| | - Shadreck Mulenga
- Ministry of Health, National Malaria Control Programme, Lilongwe, Malawi.
| | - Doreen Ali
- Ministry of Health, National Malaria Control Programme, Lilongwe, Malawi.
| | | | - Wilfred Dodoli
- World Health Organization, Country Office, Lilongwe, Malawi.
| | - John M Govere
- Malaria Vector Control Consultant, Nelspruit, Mpumalanga, South Africa.
| | - John Gimnig
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
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19
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Vanden Eng JL, Chan A, Abílio AP, Wolkon A, Ponce de Leon G, Gimnig J, Morgan J. Bed Net Durability Assessments: Exploring a Composite Measure of Net Damage. PLoS One 2015; 10:e0128499. [PMID: 26047494 PMCID: PMC4457879 DOI: 10.1371/journal.pone.0128499] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 04/27/2015] [Indexed: 11/18/2022] Open
Abstract
Background The durability of Long Lasting Insecticidal Nets (LLINs) in field conditions is of great importance for malaria prevention and control efforts; however, the physical integrity of the net fabric is not well understood making it challenging to determine overall effectiveness of nets as they age. The 2011 World Health Organization Pesticide Evaluation Scheme (WHOPES) guidelines provide a simple, standardized method using a proportional hole index (PHI) for assessing net damage with the intent to provide national malaria control programs with guidelines to assess the useful life of LLINS and estimate the rate of replacement. Methods We evaluated the utility of the PHI measure using 409 LLINs collected over three years in Nampula Province, Mozambique following a mass distribution campaign in 2008. For each LLIN the diameter and distance from the bottom of the net were recorded for every hole. Holes were classified into four size categories and a PHI was calculated following WHOPES guidelines. We investigate how the size, shape, and location of holes influence the PHI. The areas of the WHOPES defined categories were compared to circular and elliptical areas based on approximate shape and actual measured axes of each hole and the PHI was compared to cumulative damaged surface area of the LLIN. Results The damaged area of small, medium, large, and extra-large holes was overestimated using the WHOPES categories compared to elliptical areas using the actual measured axes. Similar results were found when comparing to circular areas except for extra-large holes which were underestimated. (Wilcoxon signed rank test of differences p< 0.0001 for all sizes). Approximating holes as circular overestimated hole surface area by 1.5 to 2 times or more. There was a significant difference in the mean number of holes < 0.5 cm by brand and there were more holes of all sizes on the bottom of nets than the top. For a range of hypothetical PHI thresholds used to designate a “failed LLIN”, roughly 75 to 80% of failed LLINs were detected by considering large and extra-large holes alone, but sensitivity varied by brand. Conclusions Future studies may refine the PHI to better approximate overall damaged surface area. Furthermore, research is needed to identify whether or not appropriate PHI thresholds can be used to deem a net no longer protective. Once a cutoff is selected, simpler methods of determining the effective lifespan of LLINs can help guide replacement strategies for malaria control programs.
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Affiliation(s)
- Jodi L. Vanden Eng
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- * E-mail:
| | - Adeline Chan
- Entomology Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Ana Paula Abílio
- Instituto Nacional da Saúde, Ministério da Saúde, Maputo, Mozambique
| | - Adam Wolkon
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Gabriel Ponce de Leon
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- United States President’s Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - John Gimnig
- Entomology Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Juliette Morgan
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- United States President’s Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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20
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Chanda E, Mzilahowa T, Chipwanya J, Ali D, Troell P, Dodoli W, Mnzava AP, Ameneshewa B, Gimnig J. Scale-up of integrated malaria vector control: lessons from Malawi. Bull World Health Organ 2015; 94:475-80. [PMID: 27274600 PMCID: PMC4890203 DOI: 10.2471/blt.15.154245] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 12/05/2015] [Accepted: 12/15/2015] [Indexed: 11/27/2022] Open
Abstract
Problem Indoor residual spraying and long-lasting insecticidal nets (LLINs) are key tools for malaria vector control. Malawi has struggled to scale up indoor residual spraying and to improve LLIN coverage and usage. Approach In 2002, the Malawian National Malaria Control Programme developed guidelines for insecticide treated net distribution to reach the strategic target of at least 60% coverage of households with an LLIN. By 2005, the target coverage was 80% of households and the Global Fund financed the scale-up. The US President’s Malaria Initiative funded the indoor residual spraying intervention. Local setting Malawi’s entire population is considered to be at risk of malaria. Poor vector control, insecticide resistance in malaria vectors and insufficient technical and financial support have exacerbated the malaria burden. Relevant changes Between 2002 and 2012, 18 248 206 LLINs had been distributed. The coverage of at least one LLIN per household increased from 27% (3689/13 664) to 58% (1974/3404). Indoor residual spraying coverage increased from 28 227 to 653 592 structures between 2007 and 2011. However, vector resistance prompted a switch from pyrethroids to organophosphates for indoor residual spraying, which increased the cost and operations needed to be cut back from seven to one district. Malaria cases increased from 2 853 315 in 2002 to 6 748 535 in 2010, and thereafter dropped to 4 922 596 in 2012. Lessons learnt A single intervention-based approach for vector control may have suboptimal impact. Well-coordinated integrated vector management may offer greater benefits. A resistance management plan is essential for effective and sustainable vector control.
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Affiliation(s)
- Emmanuel Chanda
- Malaria Vector Control Consultant, 11 Granite Street, Off Kamwala South Road, Plot 33421/917, PO Box 30146, Kamwala South, 10101 Lusaka, Zambia
| | | | - John Chipwanya
- Ministry of Health, National Malaria Control Programme, Lilongwe, Malawi
| | - Doreen Ali
- Ministry of Health, National Malaria Control Programme, Lilongwe, Malawi
| | - Peter Troell
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America (USA)
| | - Wilfred Dodoli
- World Health Organization, Country Office, Lilongwe, Malawi
| | - Abraham P Mnzava
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | - John Gimnig
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America (USA)
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21
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Lindblade KA, Mwandama D, Mzilahowa T, Steinhardt L, Gimnig J, Shah M, Bauleni A, Wong J, Wiegand R, Howell P, Zoya J, Chiphwanya J, Mathanga DP. A cohort study of the effectiveness of insecticide-treated bed nets to prevent malaria in an area of moderate pyrethroid resistance, Malawi. Malar J 2015; 14:31. [PMID: 25627987 PMCID: PMC4318190 DOI: 10.1186/s12936-015-0554-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 01/07/2015] [Indexed: 11/19/2022] Open
Abstract
Background Insecticide-treated bed nets (ITNs) are the cornerstone of malaria control in sub-Saharan Africa but their effectiveness may be compromised by the spread of pyrethroid resistance among malaria vectors. The objective of this investigation was to assess the effectiveness of ITNs to prevent malaria in an area of Malawi with moderate pyrethroid resistance. Methods One deltamethrin ITN was distributed in the study area for every two individuals in each household plus one extra ITN for households with an odd number of residents. A fixed cohort of 1,199 children aged six to 59 months was seen monthly for one year and at sick visits to measure malaria infection and use of ITNs. Insecticide resistance among malaria vectors was measured. The effect of ITN use on malaria incidence was assessed, adjusting for potential confounders using generalized estimating equations accounting for repeated measures. Results There were 1,909 infections with Plasmodium falciparum over 905 person-years at risk (PYAR), resulting in an observed incidence of 2.1 infections per person-year (iPPY). ITNs were used during 97% of the PYAR. The main vector was Anopheles funestus: mortality in WHO tube assays after exposure to 0.05% deltamethrin was 38% (95% confidence interval (CI) 29–47), and resistance was due to elevated oxidase enzymes. After adjusting for potential confounders, the incidence of malaria infection among ITN users was 1.7 iPPY (95% CI 1.5-2.1) and among non-bed net users was 2.6 iPPY (95% CI 2.0-3.3). Use of ITNs reduced the incidence of malaria infection by 30% (rate ratio 0.7; 95% CI, 0.5-0.8) compared to no bed nets. Conclusion ITNs significantly reduced the incidence of malaria infection in children in an area with moderate levels of pyrethroid resistance and considerable malaria transmission. This is the first study to show that ITNs provide protection in areas where pyrethroid-resistant An. funestus is the major malaria vector. Malaria control programmes should continue to distribute and promote ITNs in areas with low to moderate pyrethroid resistance; however, insecticide resistance may intensify further and it is not known whether ITNs will remain effective at higher levels of resistance. There is an urgent need to identify or develop new insecticides and technologies to limit the vulnerability of ITNs to insecticide resistance.
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Affiliation(s)
- Kim A Lindblade
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Dyson Mwandama
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Themba Mzilahowa
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Laura Steinhardt
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Monica Shah
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Andy Bauleni
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Jacklyn Wong
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Ryan Wiegand
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Paul Howell
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - John Zoya
- National Malaria Control Programme, Ministry of Public Health, Lilongwe, Malawi.
| | - John Chiphwanya
- National Malaria Control Programme, Ministry of Public Health, Lilongwe, Malawi.
| | - Don P Mathanga
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
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Abstract
BACKGROUND Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). OBJECTIVES To evaluate the effectiveness of mosquito LSM for preventing malaria. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. SELECTION CRITERIA We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. DATA COLLECTION AND ANALYSIS At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software. MAIN RESULTS We included 13 studies; four cluster-RCTs, eight controlled before-and-after trials, and one randomized cross-over trial. The included studies evaluated habitat modification (one study), habitat modification with larviciding (two studies), habitat manipulation (one study), habitat manipulation plus larviciding (two studies), or larviciding alone (seven studies) in a wide variety of habitats and countries. Malaria incidenceIn two cluster-RCTs undertaken in Sri Lanka, larviciding of abandoned mines, streams, irrigation ditches, and rice paddies reduced malaria incidence by around three-quarters compared to the control (RR 0.26, 95% CI 0.22 to 0.31, 20,124 participants, two trials, moderate quality evidence). In three controlled before-and-after trials in urban and rural India and rural Kenya, results were inconsistent (98,233 participants, three trials, very low quality evidence). In one trial in urban India, the removal of domestic water containers together with weekly larviciding of canals and stagnant pools reduced malaria incidence by three quarters. In one trial in rural India and one trial in rural Kenya, malaria incidence was higher at baseline in intervention areas than in controls. However dam construction in India, and larviciding of streams and swamps in Kenya, reduced malaria incidence to levels similar to the control areas. In one additional randomized cross-over trial in the flood plains of the Gambia River, where larval habitats were extensive and ill-defined, larviciding by ground teams did not result in a statistically significant reduction in malaria incidence (2039 participants, one trial). Parasite prevalenceIn one cluster-RCT from Sri Lanka, larviciding reduced parasite prevalence by almost 90% (RR 0.11, 95% CI 0.05 to 0.22, 2963 participants, one trial, moderate quality evidence). In five controlled before-and-after trials in Greece, India, the Philippines, and Tanzania, LSM resulted in an average reduction in parasite prevalence of around two-thirds (RR 0.32, 95% CI 0.19 to 0.55, 8041 participants, five trials, moderate quality evidence). The interventions in these five trials included dam construction to reduce larval habitats, flushing of streams, removal of domestic water containers, and larviciding. In the randomized cross-over trial in the flood plains of the Gambia River, larviciding by ground teams did not significantly reduce parasite prevalence (2039 participants, one trial). AUTHORS' CONCLUSIONS In Africa and Asia, LSM is another policy option, alongside LLINs and IRS, for reducing malaria morbidity in both urban and rural areas where a sufficient proportion of larval habitats can be targeted. Further research is needed to evaluate whether LSM is appropriate or feasible in parts of rural Africa where larval habitats are more extensive.
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Affiliation(s)
- Lucy S Tusting
- London School of Hygiene and Tropical MedicineDepartment of Disease ControlLondonUK
| | - Julie Thwing
- US Centers for Disease Control and Prevention (CDC)Strategic and Applied Science Unit, Malaria Branch4770 Buford Highway, NEMailstop F‐22AtlantaUSAGA 30341
| | - David Sinclair
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
| | - Ulrike Fillinger
- London School of Hygiene and Tropical MedicineDepartment of Disease ControlLondonUK
| | - John Gimnig
- US Centers for Disease Control and Prevention (CDC)Entomology Branch4770 Buford Highway, NEMailstop F‐42AtlantaUSAGA 30341
| | - Kimberly E Bonner
- Princeton UniversityWoodrow Wilson School of Public and International AffairsPrincetonUSA08544‐1013
| | - Christian Bottomley
- London School of Hygiene and Tropical MedicineMRC Tropical Epidemiology GroupKeppel StreetLondonUKWC1E 7HT
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Huho B, Briët O, Seyoum A, Sikaala C, Bayoh N, Gimnig J, Okumu F, Diallo D, Abdulla S, Smith T, Killeen G. Consistently high estimates for the proportion of human exposure to malaria vector populations occurring indoors in rural Africa. Int J Epidemiol 2013; 42:235-47. [PMID: 23396849 PMCID: PMC3600624 DOI: 10.1093/ije/dys214] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are highly effective tools for controlling malaria transmission in Africa because the most important vectors, from the Anopheles gambiae complex and the A. funestus group, usually prefer biting humans indoors at night. Methods Matched surveys of mosquito and human behaviour from six rural sites in Burkina Faso, Tanzania, Zambia, and Kenya, with ITN use ranging from 0.2% to 82.5%, were used to calculate the proportion of human exposure to An. gambiae sensu lato and An. funestus s.l. that occurs indoors (πi), as an indicator of the upper limit of personal protection that indoor vector control measures can provide. This quantity was also estimated through use of a simplified binary analysis (πiB) so that the proportions of mosquitoes caught indoors (Pi), and between the first and last hours at which most people are indoors (Pfl) could also be calculated as underlying indicators of feeding by mosquitoes indoors or at night, respectively. Results The vast majority of human exposure to Anopheles bites occurred indoors (πiB = 0.79–1.00). Neither An. gambiae s.l. nor An. funestus s.l. strongly preferred feeding indoors (Pi = 0.40–0.63 and 0.22–0.69, respectively), but they overwhelmingly preferred feeding at times when most humans were indoors (Pfl = 0.78–1.00 and 0.86–1.00, respectively). Conclusions These quantitative summaries of behavioural interactions between humans and mosquitoes constitute a remarkably consistent benchmark with which future observations of vector behaviour can be compared. Longitudinal monitoring of these quantities is vital to evaluate the effectiveness of ITNs and IRS and the need for complementary measures that target vectors outdoors.
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Affiliation(s)
- Bernadette Huho
- Environmental Sciences Thematic Group, Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
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Huho B, Briët O, Seyoum A, Sikaala C, Bayoh N, Gimnig J, Okumu F, Diallo D, Abdulla S, Smith T, Killeen G. Consistently high baseline estimates for the proportion of human exposure to rural African malaria vector populations that occurred indoors. Malar J 2012. [PMCID: PMC3474260 DOI: 10.1186/1475-2875-11-s1-p50] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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25
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Skarbinski J, Mwandama D, Wolkon A, Luka M, Jafali J, Smith A, Mzilahowa T, Gimnig J, Campbell C, Chiphwanya J, Ali D, Mathanga DP. Impact of indoor residual spraying with lambda-cyhalothrin on malaria parasitemia and anemia prevalence among children less than five years of age in an area of intense, year-round transmission in Malawi. Am J Trop Med Hyg 2012; 86:997-1004. [PMID: 22665608 PMCID: PMC3366547 DOI: 10.4269/ajtmh.2012.11-0621] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Little is known about the impact of indoor residual spraying (IRS) in areas with intense malaria transmission such as sub-Saharan Africa. In Malawi, IRS with lambda-cyhalothrin has been applied annually in an area of intense year-long transmission since 2007. We evaluated the impact of IRS on parasitemia and anemia prevalence in children less than five years of age by using a cross-sectional household survey conducted in 2009, six months after the second IRS spray round. We measured malaria parasitemia and anemia (hemoglobin level < 11 g/dL) in 899 children less than five years of age and used binomial regression to assess the impact of IRS by comparing children living in a household sprayed with IRS (direct IRS) with those in a household not sprayed with IRS, but in an IRS area (indirect IRS) and those living in a household not sprayed with IRS and not in an IRS area (no IRS). In the IRS area, 77% of households reported receiving IRS. Adjusting for bed net use, house construction, and socioeconomic status, we found that receiving direct IRS and indirect IRS were significantly associated with a 33% (95% confidence interval [CI] = 1–54%) and 46% (95% CI = 20–64%) reduction in parasitemia and a 21% (95% CI = 4–34%) and 30% (95% CI = 12–45%) reduction in anemia prevalence, respectively.
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Affiliation(s)
- Jacek Skarbinski
- *Address correspondence to Jacek Skarbinski, Malaria Branch, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Mailstop F22, Atlanta, GA 30341. E-mail:
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Hamel MJ, Otieno P, Bayoh N, Kariuki S, Were V, Marwanga D, Laserson KF, Williamson J, Slutsker L, Gimnig J. The combination of indoor residual spraying and insecticide-treated nets provides added protection against malaria compared with insecticide-treated nets alone. Am J Trop Med Hyg 2012; 85:1080-6. [PMID: 22144448 DOI: 10.4269/ajtmh.2011.10-0684] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Both insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS) reduce malaria in high malaria transmission areas. The combined effect of these interventions is unknown. We conducted a non-randomized prospective cohort study to determine protective efficacy of IRS with ITNs (ITN + IRS) compared with ITNs alone (ITN only) in preventing Plasmodium falciparum parasitemia. At baseline, participants provided blood samples for malaria smears, were presumptively treated for malaria, and received ITNs. Blood smears were made monthly and at sick visits. In total, 1,804 participants were enrolled. Incidence of P. falciparum parasitemia in the ITN + IRS and ITN only groups was 18 and 44 infections per 100 persons-years at risk, respectively (unadjusted rate ratio = 0.41; 95% confidence interval [CI] = 0.31-0.56). Adjusted protective efficacy of ITN + IRS compared with ITN only was 62% (95% CI = 0.50-0.72). The combination of IRS and ITN might be a feasible strategy to further reduce malaria transmission in areas of persistent perennial malaria transmission.
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Affiliation(s)
- Mary J Hamel
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia 30301, USA.
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Kilian A, Byamukama W, Pigeon O, Gimnig J, Atieli F, Koekemoer L, Protopopoff N. Evidence for a useful life of more than three years for a polyester-based long-lasting insecticidal mosquito net in Western Uganda. Malar J 2011; 10:299. [PMID: 21992483 PMCID: PMC3212829 DOI: 10.1186/1475-2875-10-299] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2011] [Accepted: 10/13/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLIN) are now standard for the prevention of malaria. However, only products with recommendation for public use from the World Health Organization should be used and this evaluation includes the assessment of net effectiveness after three years of field use. Results for one of the polyester-based products, Interceptor is presented. METHODS In five villages, 190 LLIN and 90 nets conventionally treated with the insecticide alpha-cypermethrin at 25 mg/m2 were distributed randomly and used by the families. Following a baseline household survey a net survey was carried out every six months to capture use, washing habits and physical condition of the nets. Randomly selected nets were collected after 6, 12, 24, 36 and 42 months and tested for remaining insecticide content and ability to knock-down and kill malaria transmitting mosquitoes. RESULTS During the three and a half years of observation only 16 nets were lost to follow-up resulting in an estimated attrition rate of 12% after three and 20/% after 3.5 years. Nets were used regularly and washed on average 1.5 times per year. After three and a half years 29% of the nets were still in good condition while 13% were seriously torn with no difference between the LLIN and control nets. The conventionally treated nets quickly lost insecticide and after 24 months only 7% of the original dose remained (1.6 mg/m2). Baseline median concentration of alpha-cypermethrin for LLIN was 194.5 mg/m2 or 97% of the target dose with between and within net variation of 11% and 4% respectively (relative standard deviation). On the LLIN 73.8 mg/m2 alpha-cypermethrin remained after three years of use and 56.2 mg/m2 after three and a half and 94% and 81% of the LLIN still had > 15 mg/m2 left respectively. Optimal effectiveness in bio-assays (≥ 95% 60 minute knock-down or ≥ 80% 24 hour mortality) was found in 83% of the sampled LLIN after three and 71% after three and a half years. CONCLUSIONS Under conditions in Western Uganda the tested long-lasting insecticidal net Interceptor fulfilled the criteria for phase III of WHO evaluations and, based on preliminary criteria of the useful life, this product is estimated to last on average between three and four years.
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Thwing J, Fillinger U, Gimnig J, Newman R, Lindsay S. Mosquito larval source management for controlling malaria. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2011. [DOI: 10.1002/14651858.cd008923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gatei W, Kariuki S, Hawley W, ter Kuile F, Terlouw D, Phillips-Howard P, Nahlen B, Gimnig J, Lindblade K, Walker E, Hamel M, Crawford S, Williamson J, Slutsker L, Shi YP. Effects of transmission reduction by insecticide-treated bed nets (ITNs) on parasite genetics population structure: I. The genetic diversity of Plasmodium falciparum parasites by microsatellite markers in western Kenya. Malar J 2010; 9:353. [PMID: 21134282 PMCID: PMC3004940 DOI: 10.1186/1475-2875-9-353] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 12/06/2010] [Indexed: 11/13/2022] Open
Abstract
Background Insecticide-treated bed nets (ITNs) reduce malaria transmission and are an important prevention tool. However, there are still information gaps on how the reduction in malaria transmission by ITNs affects parasite genetics population structure. This study examined the relationship between transmission reduction from ITN use and the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya. Methods Parasite genetic diversity was assessed by scoring eight single copy neutral multilocus microsatellite (MS) markers in samples collected from P. falciparum-infected children (< five years) before introduction of ITNs (1996, baseline, n = 69) and five years after intervention (2001, follow-up, n = 74). Results There were no significant changes in overall high mixed infections and unbiased expected heterozygosity between baseline (%MA = 94% and He = 0.75) and follow up (%MA = 95% and He = 0.79) years. However, locus specific analysis detected significant differences for some individual loci between the two time points. Pfg377 loci, a gametocyte-specific MS marker showed significant increase in mixed infections and He in the follow up survey (%MA = 53% and He = 0.57) compared to the baseline (%MA = 30% and He = 0.29). An opposite trend was observed in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at the Pfg377 and TAA60 loci (FST = 0.117 and 0.137 respectively) between the baseline and post-ITN parasite populations. Further analysis revealed linkage disequilibrium (LD) of the microsatellites in the baseline (14 significant pair-wise tests and ISA = 0.016) that was broken in the follow up parasite population (6 significant pairs and ISA = 0.0003). The locus specific change in He, the moderate population differentiation and break in LD between the baseline and follow up years suggest an underlying change in population sub-structure despite the stability in the overall genetic diversity and multiple infection levels. Conclusions The results from this study suggest that although P. falciparum population maintained an overall stability in genetic diversity after five years of high ITN coverage, there was significant locus specific change associated with gametocytes, marking these for further investigation.
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Affiliation(s)
- Wangeci Gatei
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Odiere M, Bayoh MN, Gimnig J, Vulule J, Irungu L, Walker E. Sampling outdoor, resting Anopheles gambiae and other mosquitoes (Diptera: Culicidae) in western Kenya with clay pots. J Med Entomol 2007; 44:14-22. [PMID: 17294916 PMCID: PMC4106366 DOI: 10.1603/0022-2585(2007)44[14:soraga]2.0.co;2] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Clay pots were analyzed as devices for sampling the outdoor resting fraction of Anopheles gambiae Giles (Diptera: Culicidae) and other mosquito species in a rural, western Kenya. Clay pots (Anopheles gambiae resting pots, herein AgREPOTs), outdoor pit shelters, indoor pyrethrum spray collections (PSC), and Colombian curtain exit traps were compared in collections done biweekly for nine intervals from April to June 2005 in 20 housing compounds. Of 10,517 mosquitoes sampled, 4,668 An. gambiae s.l. were sampled in total of which 63% were An. gambiae s.s. (46% female) and 37% were An. arabiensis (66% female). The clay pots were useful and practical for sampling both sexes of An. gambiae s.l. Additionally, 617 An. funestus (58% female) and 5,232 Culex spp. (males and females together) were collected. Temporal changes in abundance of An. gambiae s.l. were similarly revealed by all four sampling methods, indicating that the clay pots could be used as devices to quantify variation in mosquito population density. Dispersion patterns of the different species and sexes fit well the negative binomial distribution, indicating that the mosquitoes were aggregated in distribution. Aside from providing a useful sampling tool, the AgREPOT also may be useful as a delivery vehicle for insecticides or pathogens to males and females that enter and rest in them.
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Affiliation(s)
- M. Odiere
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Zoology, University of Nairobi, Nairobi, Kenya
| | - M. N. Bayoh
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisumu, Kenya
| | - J. Gimnig
- Centers for Disease Control and Prevention, Malaria Branch, Chamblee, GA 30341
| | - J. Vulule
- Vector Biology and Control Research Centre, Kenya Medical Research Institute, Kisumu, Kenya
| | - L. Irungu
- Department of Zoology, University of Nairobi, Nairobi, Kenya
| | - E. Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
- Corresponding author,
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Lindblade KA, Dotson E, Hawley WA, Bayoh N, Williamson J, Mount D, Olang G, Vulule J, Slutsker L, Gimnig J. Evaluation of long-lasting insecticidal nets after 2 years of household use. Trop Med Int Health 2005; 10:1141-50. [PMID: 16262739 DOI: 10.1111/j.1365-3156.2005.01501.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Development of long-lasting insecticidal nets (LLINs) may eliminate the need for insecticide retreatment of ITNs. While two LLINs (Olyset, Sumitomo Chemical Co., Japan; and PermaNet 1.0, Vestergaard-Frandsen, Denmark) have received recommendations from the World Health Organization Pesticide Evaluation Scheme, field-testing under normal use has been limited. We used a survival analysis approach to compare time to net failure of conventional polyester bednets treated only with deltamethrin to two LLINs and two candidate LLINs (Olyset; PermaNet; Insector, Athanor, France; and Dawa, Siamdutch Mosquito Netting Co., Thailand). Additionally, we evaluated nets treated with a process designed to increase the wash-durability of permethrin-treated nets through the addition of cyclodextrin (a starch) in the treatment process. Houses in western Kenya were randomly assigned to one of the six net types and nets were distributed to cover all sleeping spaces. Households were visited monthly to assess reported side effects in inhabitants and washing frequency. Nets were evaluated for insecticidal activity by periodic WHO cone bioassays with mortality assessed at 24 h. Nets with bioassay mortality <70% were assayed monthly until failure, defined as the first of two consecutive bioassay mortality rates <50%. Time to failure was analyzed using an extended Cox Proportional Hazards model controlling for the cumulative number of washes. We distributed 314 nets to 177 households in June-July 2002; 22 nets (7.0%) were lost to follow-up and 196 (62.4%) failed during the first 2 years of the evaluation. Controlling for cumulative number of washes, PermaNet 1.0 [Hazard Ratio (HR) 0.14, 95% Confidence Interval (CI) 0.06-0.31] had a significantly lower risk of failure than conventional nets while Insector had a significantly higher risk of failure (HR 2.57, 95% CI 1.06-4.15). The risks of failure of the remaining nets (Olyset: HR 1.29, 95% CI 0.79-2.10; Dawa: HR 0.58, 95% CI 0.32-1.18; cyclodextrin: HR 0.65, 95% CI 0.40-1.1) were not significantly different from that of a conventional net. PermaNet 1.0 performed significantly better than conventional nets and should be recommended to malaria control programs.
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Affiliation(s)
- Kim A Lindblade
- Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
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Hackett BJ, Gimnig J, Guelbeogo W, Costantini C, Koekemoer LL, Coetzee M, Collins FH, Besansky NJ. Ribosomal DNA internal transcribed spacer (ITS2) sequences differentiate Anopheles funestus and An. rivulorum, and uncover a cryptic taxon. Insect Mol Biol 2000; 9:369-374. [PMID: 10971714 DOI: 10.1046/j.1365-2583.2000.00198.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Differentiation among the closely related Afrotropical species comprising the Funestus Group is difficult by traditional taxonomic measures. Anopheles rivulorum is the second most abundant and widespread species in the Funestus Group, and is occasionally collected indoors along with the dominant member and major malaria vector, An. funestus. The prospect of misidentification of An. rivulorum as An. funestus prompted the development of a rapid, polymerase chain reaction (PCR)-based method for identifying these two species. The ribosomal internal transcribed spacer 2 (ITS2) was amplified from thirty-five specimens of An. rivulorum collected from the extremes of its range: Eastern Africa (Kenya), Southern Africa (South Africa) and Western Africa (Burkina Faso). The ITS2 region of An. rivulorum ( approximately 380 bp) is sufficiently different in size from the ITS2 of An. funestus ( approximately 700 bp) that these species can be distinguished by agarose gel electrophoresis of PCR products without further manipulation. Comparison of the An. rivulorum and An. funestus ITS2 nucleotide sequences revealed such extensive divergence that meaningful alignment was impossible, except for a 25 bp island near the 5' end. Intraspecific sequence comparisons revealed no variation among An. rivulorum individuals collected from the same country. However, sequence divergence was 2% between specimens from South Africa and Kenya, and nearly tenfold higher ( approximately 19%) between specimens from Burkina Faso and either South Africa or Kenya, an unprecedented level of intraspecific ITS2 divergence in Anopheles. Taken together, these data suggest that the Burkina Faso sample is not An. rivulorum, but rather a cryptic taxon within the Funestus Group.
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Affiliation(s)
- B J Hackett
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
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Arredondo-Jiménez JI, Gimnig J, Rodríguez MH, Washino RK. Genetic differences among Anopheles vestitipennis subpopulations collected using different methods in Chiapas state, southern México. J Am Mosq Control Assoc 1996; 12:396-401. [PMID: 8887216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biting activity and population genetic studies of the malaria vector Anopheles vestitipennis were conducted in southern México. Three subpopulations were collected from 2 villages; 2 subpopulations were from the same village, one on human bait and one with an animal-baited trap; the third was collected from a cattle corral in the 2nd village (280 km away SSE). The anthropophilic subpopulation had steady activity with 61% of bites occurring before midnight, significantly different from those of the 2 zoophilic subpopulations, which had 78-82% of bites before midnight and 2 biting peaks, one at 1900-2100 h and the other at 0400-0500 h. Isozyme analysis (13 enzymes) of these subpopulations indicated that differences between the 2 sympatric subpopulations (D = 0.07), collected using 2 different methods, were greater than that between the 2 allopatric ones (D = 0.03). These studies suggest the existence of 2 genetically different subpopulations of An. vestitipennis with specific host preferences.
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Affiliation(s)
- J I Arredondo-Jiménez
- Centro de Investigación de Paludismo, C.I.S.E.I., Instituto Nacional de Salud Pública, Chiapas, México
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