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Pepey A, Souris M, Kim S, Obadia T, Chy S, Ea M, Ouk S, Remoue F, Sovannaroth S, Mueller I, Witkowski B, Vantaux A. Comparing malaria risk exposure in rural Cambodia population using GPS tracking and questionnaires. Malar J 2024; 23:75. [PMID: 38475843 DOI: 10.1186/s12936-024-04890-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND The Great Mekong Subregion has attained a major decline in malaria cases and fatalities over the last years, but residual transmission hotspots remain, supposedly fueled by forest workers and migrant populations. This study aimed to: (i) characterize the fine-scale mobility of forest-goers and understand links between their daily movement patterns and malaria transmission, using parasites detection via real time polymerase chain reaction (RT PCR) and the individual exposure to Anopheles bites by quantification of anti-Anopheles saliva antibodies via enzyme-linked immunosorbent assay; (ii) assess the concordance of questionnaires and Global Positioning System (GPS) data loggers for measuring mobility. METHODS Two 28 day follow-ups during dry and rainy seasons, including a GPS tracking, questionnaires and health examinations, were performed on male forest goers representing the population at highest risk of infection. Their time spent in different land use categories and demographic data were analyzed in order to understand the risk factors driving malaria in the study area. RESULTS Malaria risk varied with village forest cover and at a resolution of only a few kilometers: participants from villages outside the forest had the highest malaria prevalence compared to participants from forest fringe's villages. The time spent in a specific environment did not modulate the risk of malaria, in particular the time spent in forest was not associated with a higher probability to detect malaria among forest-goers. The levels of antibody response to Anopheles salivary peptide among participants were significantly higher during the rainy season, in accordance with Anopheles mosquito density variation, but was not affected by sociodemographic and mobility factors. The agreement between GPS and self-reported data was only 61.9% in reporting each kind of visited environment. CONCLUSIONS In a context of residual malaria transmission which was mainly depicted by P. vivax asymptomatic infections, the implementation of questionnaires, GPS data-loggers and quantification of anti-saliva Anopheles antibodies on the high-risk group were not powerful enough to detect malaria risk factors associated with different mobility behaviours or time spent in various environments. The joint implementation of GPS trackers and questionnaires allowed to highlight the limitations of both methodologies and the benefits of using them together. New detection and follow-up strategies are still called for.
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Affiliation(s)
- Anaïs Pepey
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia.
| | - Marc Souris
- UMR Unité des Virus Emergents, UVE: Aix-Marseille Univ-IRD 190-Inserm 1207-IHU 5 Méditerranée Infection, 13005, Marseille, France
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
| | - Thomas Obadia
- Institut Pasteur, G5 Infectious Disease Epidemiology and Analytics, Université Paris Cité, 75015, Paris, France
- Institut Pasteur, Bioinformatics and Biostatistics Hub, Université Paris Cité, 75015, Paris, France
| | - Sophy Chy
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
| | - Malen Ea
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
| | - Sivkeng Ouk
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
| | - Franck Remoue
- UMR MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Siv Sovannaroth
- National Centre for Parasitology Entomology and Malaria Control (CNM), Phnom Penh 120 801, Phnom Penh, Cambodia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
- Genetic and Biology of Plasmodium Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, 5 Blvd Monivong, Phnom Penh 120 210, Phnom Penh, BP983, Cambodia
- Genetic and Biology of Plasmodium Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
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Grimée M, Tacoli C, Sandfort M, Obadia T, Taylor AR, Vantaux A, Robinson LJ, Lek D, Longley RJ, Mueller I, Popovici J, White MT, Witkowski B. Using serological diagnostics to characterize remaining high-incidence pockets of malaria in forest-fringe Cambodia. Malar J 2024; 23:49. [PMID: 38360625 PMCID: PMC10870639 DOI: 10.1186/s12936-024-04859-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Over the last decades, the number of malaria cases has drastically reduced in Cambodia. As the overall prevalence of malaria in Cambodia declines, residual malaria transmission becomes increasingly fragmented over smaller remote regions. The aim of this study was to get an insight into the burden and epidemiological parameters of Plasmodium infections on the forest-fringe of Cambodia. METHODS 950 participants were recruited in the province of Mondulkiri in Cambodia and followed up from 2018 to 2020. Whole-blood samples were processed for Plasmodium spp. identification by PCR as well as for a serological immunoassay. A risk factor analysis was conducted for Plasmodium vivax PCR-detected infections throughout the study, and for P. vivax seropositivity at baseline. To evaluate the predictive effect of seropositivity at baseline on subsequent PCR-positivity, an analysis of P. vivax infection-free survival time stratified by serological status at baseline was performed. RESULTS Living inside the forest significantly increased the odds of P. vivax PCR-positivity by a factor of 18.3 (95% C.I. 7.7-43.5). Being a male adult was also a significant predictor of PCR-positivity. Similar risk profiles were identified for P. vivax seropositivity. The survival analysis showed that serological status at baseline significantly correlated with subsequent infection. Serology is most informative outside of the forest, where 94.0% (95% C.I. 90.7-97.4%) of seronegative individuals survived infection-free, compared to 32.4% (95% C.I.: 22.6-46.6%) of seropositive individuals. CONCLUSION This study justifies the need for serological diagnostic assays to target interventions in this region, particularly in demographic groups where a lot of risk heterogeneity persists, such as outside of the forest.
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Affiliation(s)
- Mathilde Grimée
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France.
- Collège Doctoral, Sorbonne Université, Paris, France.
| | - Costanza Tacoli
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Mirco Sandfort
- Collège Doctoral, Sorbonne Université, Paris, France
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France
| | - Thomas Obadia
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
- Bioinformatics and Biostatistics Hub, Institut Pasteur, Université Paris Cité, Paris, France
| | - Aimee R Taylor
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France
| | - Amélie Vantaux
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Leanne J Robinson
- Burnet Institute, Melbourne, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Dysoley Lek
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Rhea J Longley
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Ivo Mueller
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France
- Population Health and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- National Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Michael T White
- Infectious Disease Epidemiology and Analytics, Institut Pasteur, Université Paris Cité, Paris, France.
- Malaria Parasites and Hosts, Institut Pasteur, Université Paris Cité, Paris, France.
| | - Benoît Witkowski
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
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Kotepui M, Kotepui KU, Masangkay FR, Mahittikorn A, Wilairatana P. Prevalence and proportion estimate of asymptomatic Plasmodium infection in Asia: a systematic review and meta-analysis. Sci Rep 2023; 13:10379. [PMID: 37369862 DOI: 10.1038/s41598-023-37439-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 06/21/2023] [Indexed: 06/29/2023] Open
Abstract
Asymptomatic Plasmodium infection raises a problem for the persistent transmission of malaria in low-endemic areas such as Asia. This systematic review was undertaken to estimate the prevalence and proportion of asymptomatic Plasmodium infection in Asia. The systematic review was registered at PROSPERO (ID: CRD42022373664). The research followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A comprehensive search of five databases, Ovid, Scopus, MEDLINE, PubMed, and Embase, was conducted to identify studies of asymptomatic Plasmodium infection in Asian countries. The pooled prevalence of asymptomatic Plasmodium infection, the pooled proportion of asymptomatic Plasmodium infection among all parasitised individuals, and the associated 95% confidence intervals were estimated using a random-effects model. A total of 916 articles were retrieved, and 87 articles that met the criteria were included in the systematic review. The pooled prevalence of asymptomatic Plasmodium infection among enrolled participants in Southeast Asia, South Asia, and Western Asia was 5.8%, 9.4%, and 8.4%, respectively. The pooled proportion of asymptomatic Plasmodium infection among all parasitised individuals in Southeast Asia, South Asia, and Western Asia was 89.3%, 87.2%, and 64.8%, respectively. There was a low prevalence of asymptomatic Plasmodium infection, but there was a high proportion of asymptomatic Plasmodium infection per all parasitised individuals in different parts of Asia. These results may support and facilitate elimination and control programs for asymptomatic Plasmodium infection in Asia.
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Affiliation(s)
- Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | | | - Aongart Mahittikorn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Doum D, Mclver DJ, Hustedt J, Hii J, Sovannaroth S, Lek D, Richardson JH, Tatarsky A, Lobo NF. An active and targeted survey reveals asymptomatic malaria infections among high-risk populations in Mondulkiri, Cambodia. Malar J 2023; 22:193. [PMID: 37353790 DOI: 10.1186/s12936-023-04630-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
BACKGROUND Malaria is a mosquito-borne disease that is one of the most serious public health issues globally and a leading cause of mortality in many developing countries worldwide. Knowing the prevalence of both symptomatic and asymptomatic malaria on a subnational scale allows for the estimation of the burden of parasitaemia present in the transmission system, enabling targeting and tailoring of resources towards greater impact and better use of available capacity. This study aimed to determine the PCR-based point prevalence of malaria infection, by parasite species, among three high-risk populations in Mondulkiri province, Cambodia: forest rangers, forest dwellers, and forest goers. METHODS A cross-sectional survey was performed during the transmission season in November and December 2021. Blood samples collected on filter paper from participants (n = 1301) from all target groups were screened for Plasmodium spp using PCR. RESULTS Malaria prevalence among all study participants was 6.7% for any Plasmodium species. Malaria prevalence in the forest ranger group was 8.1%, was 6.8% in forest goers, and 6.4% in forest dwellers; all infections were asymptomatic. Plasmodium vivax was detected in all participant groups, while the few Plasmodium falciparum infections were found in goers and dwellers. 81% of all infections were due to P. vivax, 9% were due to P. falciparum, 3% due to Plasmodium cynomolgi, and the rest (7%) remained undefined. Gender was associated with malaria infection prevalence, with male participants having higher odds of malaria infection than female participants (OR = 1.69, 95% CI 1.08-2.64). Passively collected malaria incidence data from the Cambodian government were also investigated. Health facility-reported malaria cases, based on rapid diagnostic tests, for the period Jan-Dec 2021 were 521 Plasmodium vivax (0.89% prevalence), 34 P. falciparum (0.06%) and four P. falciparum + mixed (0.01%)-a total of 559 cases (0.95%) for all of Mondulkiri. CONCLUSION This reservoir of asymptomatic parasitaemia may be perpetuating low levels of transmission, and thus, new strategies are required to realize the goal of eliminating malaria in Cambodia by 2025.
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Affiliation(s)
- Dyna Doum
- Health Forefront Organization, Phnom Penh, Cambodia
| | - David J Mclver
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA.
| | - John Hustedt
- Health Forefront Organization, Phnom Penh, Cambodia
| | - Jeffrey Hii
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Allison Tatarsky
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Neil F Lobo
- Malaria Elimination Initiative, University of California, San Francisco, CA, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA
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Malaria Knowledge-Base and Prevalence of Parasitaemia in Asymptomatic Adults in the Forest Zone of Ghana. Acta Parasitol 2022; 67:1719-1731. [PMID: 36261782 DOI: 10.1007/s11686-022-00629-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 10/05/2022] [Indexed: 11/01/2022]
Abstract
PURPOSE To determine the levels of knowledge, awareness and perception of malaria, and to determine the infection status among asymptomatic adults in selected districts. METHODS This descriptive, cross-sectional study recruited 849 participants from seven districts in the malaria meso-endemic forest zone of Ghana. Questionnaires were administered to elicit responses from asymptomatic adults on malaria awareness, knowledge and insecticide-treated net (ITN) usage. Capillary blood samples were taken from study subjects for malaria Rapid Diagnostic Test (RDT) and microscopy. Descriptive statistics was used to analyse quantitative and qualitative data. RESULTS Ninety-eight percent of participants were aware of malaria, 94.0% owned ITNs but only 35.5% consistently used them. Also, 56.7% correctly associated malaria with mosquitoes and 54.5% identified stagnant water as the breeding site. Twelve percent (12.2%) and 13.1% of the subjects tested positive for malaria via RDT and microscopy, respectively. Of the 111 confirmed malaria cases, 107 had Plasmodium falciparum infections, two had Plasmodium ovale infections and there were two Plasmodium falciparum-Plasmodium ovale mixed infections. CONCLUSION Awareness and knowledge of malaria was satisfactory but this did not translate into mosquito avoidance behaviour due to deep-seated perceptions and myths. With the prevalence of asymptomatic parasitaemia observed, this reservoir of infection could be dislodged with appropriate health education targeted at women in the rural communities.
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Egger JR, Han KT, Fang H, Zhou XN, Hlaing TM, Thant M, Han ZY, Wang XX, Hong T, Platt A, Simmons R, Thane TK, Meng M, Hogue J, Markwalter CF, Thi A, Htay T, Thein ZW, Paing AK, Tun ZM, Oo SM, Aung PP, Nyunt MM, Plowe CV. Temporal Dynamics of Subclinical Malaria in Different Transmission Zones of Myanmar. Am J Trop Med Hyg 2022; 107:tpmd220027. [PMID: 35895341 PMCID: PMC9490656 DOI: 10.4269/ajtmh.22-0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/19/2022] [Indexed: 12/03/2022] Open
Abstract
Countries in the Greater Mekong Subregion have committed to eliminate Plasmodium falciparum malaria by 2025. Subclinical malaria infections that can be detected by highly sensitive polymerase chain reaction (PCR) testing in asymptomatic individuals represent a potential impediment to this goal, although the extent to which these low-density infections contribute to transmission is unclear. To understand the temporal dynamics of subclinical malaria in this setting, a cohort of 2,705 participants from three epidemiologically distinct regions of Myanmar was screened for subclinical P. falciparum and P. vivax infection using ultrasensitive PCR (usPCR). Standard rapid diagnostic tests (RDTs) for P. falciparum were also performed. Individuals who tested positive for malaria by usPCR were followed for up to 12 weeks. Regression analysis was performed to estimate whether the baseline prevalence of infection and the count of repeated positive tests were associated with demographic, behavioral, and clinical factors. At enrollment, the prevalence of subclinical malaria infection measured by usPCR was 7.7% (1.5% P. falciparum monoinfection, 0.3% mixed P. falciparum and P. vivax, and 6.0% P. vivax monoinfection), while P. falciparum prevalence measured by RDT was just 0.2%. Prevalence varied by geography and was higher among older people and in those with outdoor exposure and travel. No difference was observed in either the prevalence or count of subclinical infection by time of year, indicating that even in low-endemicity areas, a reservoir of subclinical infection persists year-round. If low-density infections are shown to represent a significant source of transmission, identification of high-risk groups and locations may aid elimination efforts.
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Affiliation(s)
- Joseph R. Egger
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Kay T. Han
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Huang Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Xiao Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China
| | - Tin M. Hlaing
- Defense Services Medical Research Center, Nay Pyi Taw, Myanmar
| | - Myo Thant
- Defense Services Medical Research Center, Nay Pyi Taw, Myanmar
| | - Zay Y. Han
- Duke Global Health Institute, Duke University, Durham, North Carolina
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Xiao X. Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Tu Hong
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Alyssa Platt
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | | | - Thynn K. Thane
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Manfred Meng
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Joyce Hogue
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | | | - Aung Thi
- National Malaria Control Program, Myanmar Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Thura Htay
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Zaw W. Thein
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Aye K. Paing
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Zin M. Tun
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Swai M. Oo
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Poe P. Aung
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Myaing M. Nyunt
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Christopher V. Plowe
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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Pepey A, Obadia T, Kim S, Sovannaroth S, Mueller I, Witkowski B, Vantaux A, Souris M. Mobility evaluation by GPS tracking in a rural, low-income population in Cambodia. PLoS One 2022; 17:e0266460. [PMID: 35559983 PMCID: PMC9106150 DOI: 10.1371/journal.pone.0266460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 03/21/2022] [Indexed: 01/31/2023] Open
Abstract
Global Positioning System (GPS) technology is an effective tool for quantifying individuals' mobility patterns and can be used to understand their influence on infectious disease transmission. In Cambodia, mobility measurements have been limited to questionnaires, which are of limited efficacy in rural environments. In this study, we used GPS tracking to measure the daily mobility of Cambodian forest goers, a population at high risk of malaria, and developed a workflow adapted to local constraints to produce an optimal dataset representative of the participants' mobility. We provide a detailed assessment of the GPS tracking and analysis of the data, and highlight the associated difficulties to facilitate the implementation of similar studies in the future.
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Affiliation(s)
- Anaïs Pepey
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail:
| | - Thomas Obadia
- Department of Parasites and Insect Vectors, Infectious Diseases Epidemiology and Analytics, Institut Pasteur, Paris, France
- Département de Biologie Computationnelle, Hub de Bioinformatique et Biostatistique, Institut Pasteur, Paris, France
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Siv Sovannaroth
- National Centre for Parasitology Entomology and Malaria Control (CNM), Phnom Penh, Cambodia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Marc Souris
- UMR Unité des Virus Emergents, UVE: Aix-Marseille Univ–IRD 190–Inserm 1207–IHU 5 Méditerranée Infection, Marseille, France
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Cintyamena U, Murhandarwati EEH, Elyazar I, Probandari A, Ahmad RA. Identifying forms of interventions towards cross border malaria in the Asia-Pacific region: a scoping review protocol. BMJ Open 2022; 12:e056265. [PMID: 35168980 PMCID: PMC8852765 DOI: 10.1136/bmjopen-2021-056265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION An ambitious epidemiology strategy has been set by the WHO, targeting malaria elimination for at least 35 countries in 2030. Challenges in preventing malaria cross borders require greater attention to achieve the elimination target. This scoping review aims to identify successful forms of interventions to control malaria transmission across national borders in the Asia-Pacific region. METHODS AND ANALYSIS This scoping review will search four electronic databases (PubMed, ScienceDirect, EBSCOhost and ProQuest) limiting the time of publication to the last 10 years. Two independent reviewers will screen all titles and abstracts during the second stage. Study characteristics will be recorded; qualitative data will be extracted and evaluated, while quantitative data will be extracted and summarised. Overall, we will follow the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines. ETHICS AND DISSEMINATION This scoping review has received ethical approval from the Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada. The results will be disseminated through peer-reviewed publications, conference presentations and policy briefs.
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Affiliation(s)
- Utsamani Cintyamena
- Center for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - E Elsa Herdiana Murhandarwati
- Center for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
- Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Iqbal Elyazar
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jakarta Pusat, DKI Jakarta, Indonesia
| | - Ari Probandari
- Center for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
- Department of Public Health, Faculty of Medicine, Universitas Sebelas Maret, Surakarta, Indonesia
| | - Riris Andono Ahmad
- Center for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
- Department of Biostatistics, Epidemiology and Population Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
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Jongdeepaisal M, Ean M, Heng C, Buntau T, Tripura R, Callery JJ, Peto TJ, Conradis-Jansen F, von Seidlein L, Khonputsa P, Pongsoipetch K, Soviet U, Sovannaroth S, Pell C, Maude RJ. Acceptability and feasibility of malaria prophylaxis for forest goers: findings from a qualitative study in Cambodia. Malar J 2021; 20:446. [PMID: 34823527 PMCID: PMC8613728 DOI: 10.1186/s12936-021-03983-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND In the Greater Mekong Subregion, adults are at highest risk for malaria, particularly those who visit forests. The absence of effective vector control strategies and limited periods of exposure during forest visits suggest that chemoprophylaxis could be an appropriate strategy to protect forest goers against malaria. METHODS Alongside a clinical trial of anti-malarial chemoprophylaxis in northern Cambodia, qualitative research was conducted, including in-depth interviews and observation, to explore the acceptability of malaria prophylaxis for forest goers, the implementation opportunities, and challenges of this strategy. RESULTS Prophylaxis with artemether-lumefantrine for forest goers was found to be acceptable under trial conditions. Three factors played a major role: the community's awareness and perception of the effectiveness of prophylaxis, their trust in the provider, and malaria as a local health concern. The findings highlight how uptake and adherence to prophylaxis are influenced by the perceived balance between benefits and burden of anti-malarials which are modulated by the seasonality of forest visits and its influence on malaria risk. CONCLUSIONS The implementation of anti-malarial prophylaxis needs to consider how the preventive medication can be incorporated into existing vector-control measures, malaria testing and treatment services. The next step in the roll out of anti-malarial prophylaxis for forest visitors will require support from local health workers.
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Affiliation(s)
- Monnaphat Jongdeepaisal
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mom Ean
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chhoeun Heng
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thoek Buntau
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - James J. Callery
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Thomas J. Peto
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Franca Conradis-Jansen
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenz von Seidlein
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Panarasri Khonputsa
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kulchada Pongsoipetch
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ung Soviet
- Provincial Health Department, Stung Treng, Stung Treng Cambodia
| | - Siv Sovannaroth
- grid.452707.3National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Christopher Pell
- grid.450091.90000 0004 4655 0462Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands ,grid.509540.d0000 0004 6880 3010Department of Global Health, Amsterdam University Medical Centers - Location Academic Medical Center, Amsterdam, The Netherlands ,grid.7177.60000000084992262Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard J. Maude
- grid.501272.30000 0004 5936 4917Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.38142.3c000000041936754XHarvard TH Chan School of Public Health, Harvard University, Boston, USA ,grid.10837.3d0000000096069301The Open University, Milton Keynes, UK
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10
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Maude RJ, Ngo TD, Tran DT, Nguyen BTH, Dang DV, Tran LK, Gregory M, Maude RR, Sinha I, Pongsoipetch K, Martin NJ. Risk factors for malaria in high incidence areas of Viet Nam: a case-control study. Malar J 2021; 20:373. [PMID: 34535140 PMCID: PMC8446736 DOI: 10.1186/s12936-021-03908-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/07/2021] [Indexed: 12/05/2022] Open
Abstract
Background A key step to advancing the goal of malaria elimination in Viet Nam by 2030 is focusing limited resources for treatment and prevention to groups most at risk for malaria transmission. Methods To better understand risk factors for malaria transmission in central Viet Nam, a survey of 1000 malaria positive cases and 1000 malaria negative controls was conducted. Cases and controls were matched for age and gender and self-presented at commune health stations (CHS) in Binh Phuoc, Dak Nong and Dak Lak Provinces. Diagnoses were confirmed with microscopy, rapid diagnostic test and PCR. Participants were interviewed about 50 potential risk factors for malaria, which included information about occupation, forest visitation, travel, healthcare-seeking behaviour and prior use of anti-malaria interventions. Participants were enrolled by trained government health workers and the samples were analysed in Vietnamese government laboratories. Data were analysed by univariable, block-wise and multivariable logistic regression. Results Among cases, 61.8% had Plasmodium falciparum, 35.2% Plasmodium vivax and 3% mixed species infections. Median (IQR) age was 27 (21–36) years and 91.2% were male. Twenty-five risk factors were associated with being a case and eleven with being a control. Multivariable analysis found that malaria cases correlated with forest workers, recent forest visitation, longer duration of illness, having a recorded fever, number of malaria infections in the past year, having had prior malaria treatment and having previously visited a clinic. Conclusions This study demonstrates the benefits of increased statistical power from matched controls in malaria surveillance studies, which allows identification of additional independent risk factors. It also illustrates an example of research partnership between academia and government to collect high quality data relevant to planning malaria elimination activities. Modifiable risk factors and implications of the findings for malaria elimination strategy are presented. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03908-7.
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Affiliation(s)
- Richard J Maude
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand. .,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, OX3 7FZ, UK. .,Harvard TH Chan School of Public Health, Harvard University, Boston, USA. .,The Open University, Milton Keynes, UK.
| | - Thang Duc Ngo
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Duong Thanh Tran
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Binh Thi Huong Nguyen
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Dung Viet Dang
- National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | | | | | - Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Ipsita Sinha
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, OX3 7FZ, UK
| | - Kulchada Pongsoipetch
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
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11
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Ean M, Sanann N, Callery JJ, Pell C, Peto TJ, Tripura R, Cheah PY. Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia. Wellcome Open Res 2021; 6:46. [PMID: 34041367 PMCID: PMC8127021 DOI: 10.12688/wellcomeopenres.16574.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The “Village Drama Against Malaria” (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.
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Affiliation(s)
- Mom Ean
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand.,University Research Company, Phnom Penh, Cambodia
| | - James J Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Christopher Pell
- 3Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,The Ethox Centre, University of Oxford, Oxford, UK
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12
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Ean M, Sanann N, Callery JJ, Pell C, Peto TJ, Tripura R, Cheah PY. Theory of change: Drama and arts-based community engagement for malaria research and elimination in Cambodia. Wellcome Open Res 2021; 6:46. [PMID: 34041367 PMCID: PMC8127021 DOI: 10.12688/wellcomeopenres.16574.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2021] [Indexed: 01/24/2024] Open
Abstract
Background: Across the Greater Mekong Sub-region, malaria persists in isolated communities along international borders. Arts and drama have been used to reach to communities in Cambodia to engage them in malaria research, prevention and control. The "Village Drama Against Malaria" (VDAM) project was conducted in north eastern and western Cambodia: Stung Treng; Battambang and Pailin provinces during 2016 to 2019. In total, VDAM reached 55 rural villages, 2,378 student participants and 43,502 audience members. Methods: This article presents the results of two stakeholder-led evaluation workshops in which participants collaboratively developed theories of change to better understand the potential and actual impact of arts and drama-based activities on malaria in these communities. The workshops had a particular focus on identifying areas for monitoring and evaluation so that impact can be measured. Workshop participants included village malaria workers, community leaders, professional and student drama performers, and representatives from the local health authorities and the national malaria control programme. Results: Five broad areas were identified as relevant for monitoring and evaluation: logistical and practical challenges; embeddedness and reach of engagement; health knowledge and confidence of young people; effectiveness of communications; impact on malaria. These areas align well with the monitoring and evaluation conducted to date and point to additional opportunities for data collection. Conclusions: The findings from these workshops will inform future engagement strategies, for example, we may engage a smaller number of young people but over a longer period and more in-depth.
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Affiliation(s)
- Mom Ean
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
- University Research Company, Phnom Penh, Cambodia
| | - James J. Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
| | - Christopher Pell
- 3Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- The Ethox Centre, University of Oxford, Oxford, UK
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13
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Stratil AS, Vernaeve L, Lopes S, Bourny Y, Mannion K, Hamade P, Roca-Feltrer A, Tibenderana JK, Sovannaroth S, Debackere M. Eliminating Plasmodium falciparum malaria: results from tailoring active case detection approaches to remote populations in forested border areas in north-eastern Cambodia. Malar J 2021; 20:108. [PMID: 33618718 PMCID: PMC7898252 DOI: 10.1186/s12936-021-03622-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 02/04/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Remaining Plasmodium falciparum cases in Cambodia are concentrated in forested border areas and in remote populations who are hard to reach through passive case detection. A key approach to reach these populations is active case detection by mobile malaria workers (MMWs). However, this is operationally challenging because of changing movement patterns of the target population moving into less accessible areas. From January 2018 to December 2020, a tailored package of active case detection approaches was implemented in forested border areas of three provinces in north-eastern Cambodia to reach remote populations and support the elimination of falciparum malaria. METHODS Key elements of this project were to tailor approaches to local populations, use responsive monitoring systems, maintain operational flexibility, build strong relationships with local communities, and implement close supervision practices. MMWs were recruited from local communities. Proactive case detection approaches included mobile malaria posts positioned at frequented locations around and within forests, and locally informed outreach activities targeting more remote locations. Reactive case detection was conducted among co-travellers of confirmed cases. Testing for malaria was conducted independent of fever symptoms. Routine monitoring of programmatic data informed tactical adaptations, while supervision exercises ensured service quality. RESULTS Despite operational challenges, service delivery sites were able to maintain consistently high testing rates throughout the implementation period, with each of 45 sites testing a monthly average of 64 (SD 6) people in 2020. In 2020, project MMWs detected only 32 P. falciparum cases. Over the project period, the P. falciparum/P. vivax ratio steadily inversed. Including data from neighbouring health centres and village malaria workers, 45% (80,988/180,732) of all people tested and 39% (1280/3243) of P. falciparum cases detected in the area can be attributed to project MMWs. Remaining challenges of the last elimination phase include maintaining intensified elimination efforts, addressing the issue of detecting low parasitaemia cases and shifting focus to P. vivax malaria. CONCLUSIONS Reaching remote populations through active case detection should remain a key strategy to eliminate P. falciparum malaria. This case study presented a successful approach combining tailored proactive and reactive strategies that could be transferred to similar settings in other areas of the Greater Mekong Subregion.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control (CNM), Phnom Penh, Cambodia
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14
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Choosing interventions to eliminate forest malaria: preliminary results of two operational research studies inside Cambodian forests. Malar J 2021; 20:51. [PMID: 33472630 PMCID: PMC7818569 DOI: 10.1186/s12936-020-03572-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/24/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Rapid elimination of Plasmodium falciparum malaria in Cambodia is a goal with both national and international significance. Transmission of malaria in Cambodia is limited to forest environments, and the main population at risk consists of forest-goers who rely on forest products for income or sustenance. The ideal interventions to eliminate malaria from this population are unknown. METHODS In two forested regions of Cambodia, forest-goers were trained to become forest malaria workers (FMWs). In one region, FMWs performed mass screening and treatment, focal screening and treatment, and passive case detection inside the forest. In the other region, FMWs played an observational role for the first year, to inform the choice of intervention for the second year. In both forests, FMWs collected blood samples and questionnaire data from all forest-goers they encountered. Mosquito collections were performed in each forest. RESULTS Malaria prevalence by PCR was high in the forest, with 2.3-5.0% positive for P. falciparum and 14.6-25.0% positive for Plasmodium vivax among forest-goers in each study site. In vectors, malaria prevalence ranged from 2.1% to 9.6%, but no P. falciparum was observed. Results showed poor performance of mass screening and treatment, with sensitivity of rapid diagnostic tests equal to 9.1% (95% CI 1.1%, 29.2%) for P. falciparum and 4.4% (95% CI 1.6%, 9.2%) for P. vivax. Malaria infections were observed in all demographics and throughout the studied forests, with no clear risk factors emerging. CONCLUSIONS Malaria prevalence remains high among Cambodian forest-goers, but performance of rapid diagnostic tests is poor. More adapted strategies to this population, such as intermittent preventive treatment of forest goers, should be considered.
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15
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Sandfort M, Vantaux A, Kim S, Obadia T, Pepey A, Gardais S, Khim N, Lek D, White M, Robinson LJ, Witkowski B, Mueller I. Forest malaria in Cambodia: the occupational and spatial clustering of Plasmodium vivax and Plasmodium falciparum infection risk in a cross-sectional survey in Mondulkiri province, Cambodia. Malar J 2020; 19:413. [PMID: 33213471 PMCID: PMC7678315 DOI: 10.1186/s12936-020-03482-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/04/2020] [Indexed: 02/24/2023] Open
Abstract
Background After a marked reduction in malaria burden in Cambodia over the last decades, case numbers increased again in 2017–2018. In light of the national goal of malaria elimination by 2025, remaining pockets of high risk need to be well defined and strategies well-tailored to identify and target the persisting burden cost-effectively. This study presents species-specific prevalence estimates and risk stratification for a remote area in Cambodia. Methods A cross-sectional survey was conducted in 17 villages in the high-incidence province Mondulkiri in the dry season (December 2017 to April 2018). 4200 randomly selected participants (2–80 years old) were tested for Plasmodium infection by PCR. Risk of infection was associated with questionnaire-derived covariates and spatially stratified based on household GPS coordinates. Results The prevalence of PCR-detectable Plasmodium infection was 8.3% (349/4200) and was more than twice as high for Plasmodium vivax (6.4%, 268) than for Plasmodium falciparum (3.0%, 125, p < 0.001). 97.8% (262/268) of P. vivax and 92.8% (116/125, p < 0.05) of P. falciparum infections were neither accompanied by symptoms at the time of the interview nor detected by microscopy or RDT. Recent travels to forest sites (aOR 2.17, p < 0.01) and forest work (aOR 2.88, p < 0.001) were particularly strong risk factors and risk profiles for both species were similar. Large village-level differences in prevalence of Plasmodium infection were observed, ranging from 0.6% outside the forest to 40.4% inside. Residing in villages at the forest fringe or inside the forest compared to outside was associated with risk of infection (aOR 2.14 and 12.47, p < 0.001). Villages inside the forest formed spatial hotspots of infection despite adjustment for the other risk factors. Conclusions Persisting pockets of high malaria risk were detected in forested areas and in sub-populations engaging in forest-related activities. High levels of asymptomatic infections suggest the need of better case detection plans and the predominance of P. vivax the implementation of radical cure. In villages inside the forest, within-village exposure was indicated in addition to risk due to forest activities. Village-level stratification of targeted interventions based on forest proximity could render the elimination efforts more cost-effective and successful.
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Affiliation(s)
- Mirco Sandfort
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France. .,Sorbonne Université, Collège doctoral, Paris, France.
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Thomas Obadia
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Anaïs Pepey
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Soazic Gardais
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France
| | - Nimol Khim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Dysoley Lek
- National Centre for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia.,School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Michael White
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia
| | - Leanne J Robinson
- Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia.,University of Melbourne, Melbourne, Australia.,Burnet Institute, Melbourne, Australia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Ivo Mueller
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France.,Population Health & Immunity, Walter and Eliza Hall Institute, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
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16
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Björkman A, Morris U. Why Asymptomatic Plasmodium falciparum Infections Are Common in Low-Transmission Settings. Trends Parasitol 2020; 36:898-905. [PMID: 32855077 DOI: 10.1016/j.pt.2020.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/18/2020] [Accepted: 07/18/2020] [Indexed: 12/22/2022]
Abstract
Plasmodium falciparum infections in low-transmission settings are often asymptomatic with low parasite densities despite low herd immunity. Based on studies in Zanzibar, this may be due to parasitic (nonvirulence) rather than host (immunity) factors. In high-transmission settings, high replication rate and virulence represents a competitive advantage, whereas in low-transmission settings nonvirulent parasites escape both competition and treatment. Such parasites also survive longer in low-transmission settings due to lower host immunity response and less frequent indirect drug exposure. This has major implications for optimal malaria control and elimination strategies.
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17
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Peto TJ, Tripura R, Maude RJ. Strengthen Village Malaria Reporting to Better Target Reservoirs of Persistent Infections in Southeast Asia. Clin Infect Dis 2020; 68:1066-1067. [PMID: 30219841 PMCID: PMC6399432 DOI: 10.1093/cid/ciy793] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Affiliation(s)
- Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Richard J Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom.,Department of Epidemiology, Harvard T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts
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18
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Ethics and Antimalarial Drug Resistance. ETHICS AND DRUG RESISTANCE: COLLECTIVE RESPONSIBILITY FOR GLOBAL PUBLIC HEALTH 2020. [PMCID: PMC7586435 DOI: 10.1007/978-3-030-27874-8_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
There has been impressive progress in malaria control and treatment over the past two decades. One of the most important factors in the decline of malaria-related mortality has been the development and deployment of highly effective treatment in the form of artemisinin-based combination therapies (ACTs). However, recent reports suggest that these gains stand the risk of being reversed due to the emergence of ACT resistance in the Greater Mekong Subregion and the threat of this resistance spreading to Africa, where the majority of the world’s malaria cases occur, with catastrophic consequences. This chapter provides an overview of strategies proposed by malaria experts to tackle artemisinin-resistant malaria, and some of the most important practical ethical issues presented by each of these interventions. The proposed strategies include mass antimalarial drug administrations in selected populations, and mandatory screening of possibly infected individuals prior to entering an area free of artemisinin-resistant malaria. We discuss ethical issues such as tensions between the wishes of individuals versus the broader goal of malaria elimination, and the risks of harm to interventional populations, and conclude by proposing a set of recommendations.
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Prevalence of Asymptomatic Malaria among Children in the Tamale Metropolis: How Does the PfHRP2 CareStart™ RDT Perform against Microscopy? J Trop Med 2019; 2019:6457628. [PMID: 31933652 PMCID: PMC6942882 DOI: 10.1155/2019/6457628] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/24/2019] [Accepted: 11/26/2019] [Indexed: 11/30/2022] Open
Abstract
Background Asymptomatic carriage of the malaria parasites, likewise its misdiagnosis, especially false negatives, due to the use of substandard rapid diagnosis tests (RDTs) has been shown to hinder the progress of the fight against malaria. Method The study assessed the prevalence of asymptomatic malaria as well as the performance of Plasmodium falciparum-specific protein and histidine-rich protein 2 (PfHRP2) CareStart™ RDT against standard microscopy in the detection of malaria infection among 345 children (1–15 yrs) from two (2) basic schools in Tamale Metropolis. Results From the microscopy (considered as gold standard), prevalence of malaria among the asymptomatic children was found to be 2.6%, with sensitivity and specificity of CareStart™ RDT in detecting P. falciparum infections found to be 55.6% and 93.8%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of CareStart™ RDT were found to be 19.23% and 98.45%, respectively. There was an evidence showing a significant relation between CareStart™ RDT and microscopy in determining malaria infection (χ2 = 30.579, p < 0.001). Conclusion Prevalence of asymptomatic malaria among children was found to be 2.6%. The study reported low sensitivity and PPV for PfHRP2 CareStart™ RDT in an asymptomatic population at instances of low parasitaemia.
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20
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Sanann N, Peto TJ, Tripura R, Callery JJ, Nguon C, Bui TM, Nofal SD, von Seidlein L, Lek D, Dondorp AM, Cheah PY, Pell C. Forest work and its implications for malaria elimination: a qualitative study. Malar J 2019; 18:376. [PMID: 31771587 PMCID: PMC6880349 DOI: 10.1186/s12936-019-3008-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/16/2019] [Indexed: 11/11/2022] Open
Abstract
Background Over the last 20 years, malaria incidence has decreased across the Greater Mekong Sub-region (GMS) and the emergence of artemisinin resistance has stimulated efforts to accelerate regional elimination. In the GMS, the malaria transmission is focused increasingly in forested zones. This article describes forest-going activities and examines forest workers’ attitudes to and experiences of malaria prevention and control in north-eastern Cambodia. Methods In Stung Treng Province, Cambodia, 19 in-depth interviews were conducted in villages with participants recently diagnosed with uncomplicated falciparum malaria who reported working in forests. Two focus group discussions with respondents’ forest-working peers were held. Interviews and focus groups were audio-recorded transcribed, and translated for thematic analysis. Results Forest work is an essential source of income for respondents. Many combine it with farming, which influences the timing and duration of forest visits. Forest activities include logging and collecting other forest products, particularly malva nuts. Men log year-round, whereas gathering forest products is seasonal and can involve entire families. Forest workers sleep chiefly in unimpregnated hammock nets in make-shift encampments. Respondents are concerned about symptomatic malaria, but unfamiliar with the concept of asymptomatic infection. They view the forest as an area of potential malaria infection and seek to protect themselves from mosquito bites through wearing long-sleeved clothes, using repellents, and lighting fires. Forest workers express a willingness to self-test and self-administer anti-malarials. Conclusions Forest workers’ behaviour and perceptions of risk indicate that improvements are needed to current control measures. There is potential to: better target distribution of impregnated hammock nets; offer curative or presumptive treatment while in forests; and expand access to screening. Establishing the efficacy and feasibility of prophylaxis for forest workers in the GMS is a priority.
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Affiliation(s)
- Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,University Research Company, Phnom Penh, Cambodia
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - James J Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Thanh Mai Bui
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Dysoley Lek
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.,Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands
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21
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Imwong M, Madmanee W, Suwannasin K, Kunasol C, Peto TJ, Tripura R, von Seidlein L, Nguon C, Davoeung C, Day NPJ, Dondorp AM, White NJ. Asymptomatic Natural Human Infections With the Simian Malaria Parasites Plasmodium cynomolgi and Plasmodium knowlesi. J Infect Dis 2019; 219:695-702. [PMID: 30295822 PMCID: PMC6376906 DOI: 10.1093/infdis/jiy519] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In Southeast Asia, Plasmodium knowlesi, a parasite of long-tailed macaques (Macaca fascicularis), is an important cause of human malaria. Plasmodium cynomolgi also commonly infects these monkeys, but only one naturally acquired symptomatic human case has been reported previously. METHODS Malariometric studies involving 5422 subjects (aged 6 months to 65 years) were conducted in 23 villages in Pailin and Battambang, western Cambodia. Parasite detection and genotyping was conducted on blood samples, using high-volume quantitative PCR (uPCR). RESULTS Asymptomatic malaria parasite infections were detected in 1361 of 14732 samples (9.2%). Asymptomatic infections with nonhuman primate malaria parasites were found in 21 individuals living close to forested areas; P. cynomolgi was found in 11, P. knowlesi was found in 8, and P. vivax and P. cynomolgi were both found in 2. Only 2 subjects were female, and 14 were men aged 20-40 years. Geometric mean parasite densities were 3604 parasites/mL in P. cynomolgi infections and 52488 parasites/mL in P. knowlesi infections. All P. cynomolgi isolates had wild-type dihydrofolate reductase genes, in contrast to the very high prevalence of mutations in the human malaria parasites. Asymptomatic reappearance of P. cynomolgi occurred in 2 subjects 3 months after the first infection. CONCLUSIONS Asymptomatic naturally acquired P. cynomolgi and P. knowlesi infections can both occur in humans. CLINICAL TRIALS REGISTRATION NCT01872702.
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Affiliation(s)
- Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wanassanan Madmanee
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thomas J Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh
| | | | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
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22
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Tripura R, Peto TJ, Chea N, Chan D, Mukaka M, Sirithiranont P, Dhorda M, Promnarate C, Imwong M, von Seidlein L, Duanguppama J, Patumrat K, Huy R, Grobusch MP, Day NPJ, White NJ, Dondorp AM. A Controlled Trial of Mass Drug Administration to Interrupt Transmission of Multidrug-Resistant Falciparum Malaria in Cambodian Villages. Clin Infect Dis 2019. [PMID: 29522113 PMCID: PMC6117448 DOI: 10.1093/cid/ciy196] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background The increase in multidrug-resistant Plasmodium falciparum in Southeast Asia suggests a need for acceleration of malaria elimination. We evaluated the effectiveness and safety of mass drug administration (MDA) to interrupt malaria transmission. Methods Four malaria-endemic villages in western Cambodia were randomized to 3 rounds of MDA (a 3-day course of dihydroartemisinin with piperaquine-phosphate), administered either early in or at the end of the study period. Comprehensive malaria treatment records were collected during 2014-2017. Subclinical parasite prevalence was estimated by ultrasensitive quantitative polymerase chain reaction quarterly over 12 months. Results MDA coverage with at least 1 complete round was 88% (1999/2268), ≥2 rounds 73% (1645/2268), and all 3 rounds 58% (1310/2268). Plasmodium falciparum incidence in intervention and control villages was similar over the 12 months prior to the study: 39 per 1000 person-years (PY) vs 45 per 1000 PY (P = .50). The primary outcome, P. falciparum incidence in the 12 months after MDA, was lower in intervention villages (1.5/1000 PY vs 37.1/1000 PY; incidence rate ratio, 24.5 [95% confidence interval], 3.4-177; P = .002). Following MDA in 2016, there were no clinical falciparum malaria cases over 12 months (0/2044 PY) in all 4 villages. Plasmodium vivax prevalence decreased markedly in intervention villages following MDA but returned to approximately half the baseline prevalence by 12 months. No severe adverse events were attributed to treatment. Conclusions Mass drug administrations achieved high coverage, were safe, and associated with the absence of clinical P. falciparum cases for at least 1 year. Clinical Trials Registration NCT01872702.
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Affiliation(s)
- Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Nguon Chea
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh
| | | | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Pasathorn Sirithiranont
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mehul Dhorda
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom.,World-Wide Antimalarial Resistance Network, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cholrawee Promnarate
- World-Wide Antimalarial Resistance Network, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Jureeporn Duanguppama
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Krittaya Patumrat
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rekol Huy
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh
| | - Martin P Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Nicholas P J Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
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23
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Peto TJ, Tripura R, Sanann N, Adhikari B, Callery J, Droogleever M, Heng C, Cheah PY, Davoeung C, Nguon C, von Seidlein L, Dondorp AM, Pell C. The feasibility and acceptability of mass drug administration for malaria in Cambodia: a mixed-methods study. Trans R Soc Trop Med Hyg 2019; 112:264-271. [PMID: 29917147 PMCID: PMC6044409 DOI: 10.1093/trstmh/try053] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/16/2018] [Indexed: 01/27/2023] Open
Abstract
Background Mass drug administrations (MDAs) are part of the World Health Organization’s Plasmodium falciparum elimination strategy for the Greater Mekong Subregion (GMS). In Cambodia, a 2015–2017 clinical trial evaluated the effectiveness of MDA. This article explores factors that influence the feasibility and acceptability of MDA, including seasonal timing, financial incentives and the delivery model. Methods Quantitative data were collected through structured questionnaires from the heads of 163 households. Qualitative data were collected through 25 semi-structured interviews and 5 focus group discussions with villagers and local health staff. Calendars of village activities were created and meteorological and malaria treatment records were collected. Results MDA delivered house-to-house or at a central point, with or without compensation, were equally acceptable and did not affect coverage. People who knew about the rationale for the MDA, asymptomatic infections and transmission were more likely to participate. In western Cambodia, MDA delivered house-to-house by volunteers at the end of the dry season may be most practicable but requires the subsequent treatment of in-migrants to prevent reintroduction of infections. Conclusions For MDA targeted at individual villages or village clusters it is important to understand local preferences for community mobilisation, delivery and timing, as several models of MDA are feasible.
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Affiliation(s)
- Thomas J Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Nou Sanann
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Bipin Adhikari
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - James Callery
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mark Droogleever
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Chhouen Heng
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Chan Davoeung
- Battambang Provincial Health Department, Mohatep Street, Battambang, Cambodia
| | - Chea Nguon
- National Centre for Parasitology, Entomology and Malaria Control, 477 Betong, Khan Sen Sok, Phnom Penh, Cambodia
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
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24
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Jiram AI, Ooi CH, Rubio JM, Hisam S, Karnan G, Sukor NM, Artic MM, Ismail NP, Alias NW. Evidence of asymptomatic submicroscopic malaria in low transmission areas in Belaga district, Kapit division, Sarawak, Malaysia. Malar J 2019; 18:156. [PMID: 31046769 PMCID: PMC6498596 DOI: 10.1186/s12936-019-2786-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/22/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Malaysia has declared its aim to eliminate malaria with a goal of achieving zero local transmission by the year 2020. However, targeting the human reservoir of infection, including those with asymptomatic infection is required to achieve malaria elimination. Diagnosing asymptomatic malaria is not as straightforward due to the obvious lack of clinical manifestations and often subpatent level of parasites. Accurate diagnosis of malaria is important for providing realistic estimates of malaria burden and preventing misinformed interventions. Low levels of parasitaemia acts as silent reservoir of transmission thus remains infectious to susceptible mosquito vectors. Hence, the aim of this study is to investigate the prevalence of asymptomatic submicroscopic malaria (SMM) in the District of Belaga, Sarawak. METHODS In 2013, a total of 1744 dried blood spots (DBS) were obtained from residents of 8 longhouses who appeared healthy. Subsequently, 251 venous blood samples were collected from residents of 2 localities in 2014 based on the highest number of submicroscopic cases from prior findings. Thin and thick blood films were prepared from blood obtained from all participants in this study. Microscopic examination were carried out on all samples and a nested and nested multiplex PCR were performed on samples collected in 2013 and 2014 respectively. RESULTS No malaria parasites were detected in all the Giemsa-stained blood films. However, of the 1744 samples, 29 (1.7%) were positive for Plasmodium vivax by PCR. Additionally, of the 251 samples, the most prevalent mono-infection detected by PCR was Plasmodium falciparum 50 (20%), followed by P. vivax 39 (16%), P. knowlesi 9 (4%), and mixed infections 20 (8%). CONCLUSIONS This research findings conclude evidence of Plasmodium by PCR, among samples previously undetectable by routine blood film microscopic examination, in local ethnic minority who are clinically healthy. SMM in Belaga district is attributed not only to P. vivax, but also to P. falciparum and P. knowlesi. In complementing efforts of programme managers, there is a need to increase surveillance for SMM nationwide to estimate the degree of SMM that warrant measures to block new transmission of malaria.
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Affiliation(s)
- Adela Ida Jiram
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia.
| | - Choo Huck Ooi
- Vector Borne Diseases Section, Sarawak Health Department, Ministry of Health Malaysia, Diplomatik Road, Off Bako Road, Petra Jaya, 93050, Kuching, Sarawak, Malaysia
| | - José Miguel Rubio
- Malaria & Emerging Parasitic Diseases Laboratory, Parasitology Department, National Centre of Microbiology, Instituto de Salud Carlos III (ISCIII), Carretera de Majadahonda - Pozuelo, km. 2,200, Majadahonda, 28220, Madrid, Spain
| | - Shamilah Hisam
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Govindarajoo Karnan
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nurnadiah Mohd Sukor
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Mohd Mafie Artic
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nor Parina Ismail
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
| | - Nor Wahida Alias
- Parasitology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
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25
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Pell CL, Adhikari B, Myo Thwin M, Kajeechiwa L, Nosten S, Nosten FH, Sahan KM, Smithuis FM, Nguyen TN, Hien TT, Tripura R, Peto TJ, Sanann N, Nguon C, Pongvongsa T, Phommasone K, Mayxay M, Mukaka M, Peerawaranun P, Kaehler N, Cheah PY, Day NPJ, White NJ, Dondorp AM, von Seidlein L. Community engagement, social context and coverage of mass anti-malarial administration: Comparative findings from multi-site research in the Greater Mekong sub-Region. PLoS One 2019; 14:e0214280. [PMID: 30908523 PMCID: PMC6433231 DOI: 10.1371/journal.pone.0214280] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 03/11/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Between 2013 and 2017, targeted malaria elimination (TME), a package of interventions that includes mass drug administration (MDA)-was piloted in communities with reservoirs of asymptomatic P. falciparum across the Greater Mekong sub-Region (GMS). Coverage in target communities is a key determinant of the effectiveness of MDA. Drawing on mixed methods research conducted alongside TME pilot studies, this article examines the impact of the community engagement, local social context and study design on MDA coverage. METHODS AND FINDINGS Qualitative and quantitative data were collected using questionnaire-based surveys, semi-structured and in-depth interviews, focus group discussions, informal conversations, and observations of study activities. Over 1500 respondents were interviewed in Myanmar, Vietnam, Cambodia and Laos. Interview topics included attitudes to malaria and experiences of MDA. Overall coverage of mass anti-malarial administration was high, particularly participation in at least a single round (85%). Familiarity with and concern about malaria prompted participation in MDA; as did awareness of MDA and familiarity with the aim of eliminating malaria. Fear of adverse events and blood draws discouraged people. Hence, community engagement activities sought to address these concerns but their impact was mediated by the trust relationships that study staff could engender in communities. In contexts of weak healthcare infrastructure and (cash) poverty, communities valued the study's ancillary care and the financial compensation. However, coverage did not necessarily decrease in the absence of cash compensation. Community dynamics, affected by politics, village conformity, and household decision-making also affected coverage. CONCLUSIONS The experimental nature of TME presented particular challenges to achieving high coverage. Nonetheless, the findings reflect those from studies of MDA under implementation conditions and offer useful guidance for potential regional roll-out of MDA: it is key to understand target communities and provide appropriate information in tailored ways, using community engagement that engenders trust.
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Affiliation(s)
- Christopher L. Pell
- Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Suphak Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Francois H. Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Sorbonne Universités, UPMC Univ Paris 06, UPMC UMRS CR7, Paris, France
| | - Kate M. Sahan
- Ethox Centre and Wellcome Centre for Ethics and Humanities, Nuffield Department of Population Health, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Frank M. Smithuis
- Medical Action Myanmar, Yangon, Myanmar
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Thuy-Nhien Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Asia Programme, Ho Chi Minh City, Vietnam
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Wellcome Trust Asia Programme, Ho Chi Minh City, Vietnam
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nou Sanann
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao PDR
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao PDR
- Institute of Research and Educational Development, University of Health Sciences, Vientiane, Lao PDR
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pimnara Peerawaranun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nils Kaehler
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Ethox Centre and Wellcome Centre for Ethics and Humanities, Nuffield Department of Population Health, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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von Seidlein L, Peto TJ, Landier J, Nguyen TN, Tripura R, Phommasone K, Pongvongsa T, Lwin KM, Keereecharoen L, Kajeechiwa L, Thwin MM, Parker DM, Wiladphaingern J, Nosten S, Proux S, Corbel V, Tuong-Vy N, Phuc-Nhi TL, Son DH, Huong-Thu PN, Tuyen NTK, Tien NT, Dong LT, Hue DV, Quang HH, Nguon C, Davoeung C, Rekol H, Adhikari B, Henriques G, Phongmany P, Suangkanarat P, Jeeyapant A, Vihokhern B, van der Pluijm RW, Lubell Y, White LJ, Aguas R, Promnarate C, Sirithiranont P, Malleret B, Rénia L, Onsjö C, Chan XH, Chalk J, Miotto O, Patumrat K, Chotivanich K, Hanboonkunupakarn B, Jittmala P, Kaehler N, Cheah PY, Pell C, Dhorda M, Imwong M, Snounou G, Mukaka M, Peerawaranun P, Lee SJ, Simpson JA, Pukrittayakamee S, Singhasivanon P, Grobusch MP, Cobelens F, Smithuis F, Newton PN, Thwaites GE, Day NPJ, Mayxay M, Hien TT, Nosten FH, Dondorp AM, White NJ. The impact of targeted malaria elimination with mass drug administrations on falciparum malaria in Southeast Asia: A cluster randomised trial. PLoS Med 2019; 16:e1002745. [PMID: 30768615 PMCID: PMC6377128 DOI: 10.1371/journal.pmed.1002745] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The emergence and spread of multidrug-resistant Plasmodium falciparum in the Greater Mekong Subregion (GMS) threatens global malaria elimination efforts. Mass drug administration (MDA), the presumptive antimalarial treatment of an entire population to clear the subclinical parasite reservoir, is a strategy to accelerate malaria elimination. We report a cluster randomised trial to assess the effectiveness of dihydroartemisinin-piperaquine (DP) MDA in reducing falciparum malaria incidence and prevalence in 16 remote village populations in Myanmar, Vietnam, Cambodia, and the Lao People's Democratic Republic, where artemisinin resistance is prevalent. METHODS AND FINDINGS After establishing vector control and community-based case management and following intensive community engagement, we used restricted randomisation within village pairs to select 8 villages to receive early DP MDA and 8 villages as controls for 12 months, after which the control villages received deferred DP MDA. The MDA comprised 3 monthly rounds of 3 daily doses of DP and, except in Cambodia, a single low dose of primaquine. We conducted exhaustive cross-sectional surveys of the entire population of each village at quarterly intervals using ultrasensitive quantitative PCR to detect Plasmodium infections. The study was conducted between May 2013 and July 2017. The investigators randomised 16 villages that had a total of 8,445 residents at the start of the study. Of these 8,445 residents, 4,135 (49%) residents living in 8 villages, plus an additional 288 newcomers to the villages, were randomised to receive early MDA; 3,790 out of the 4,423 (86%) participated in at least 1 MDA round, and 2,520 out of the 4,423 (57%) participated in all 3 rounds. The primary outcome, P. falciparum prevalence by month 3 (M3), fell by 92% (from 5.1% [171/3,340] to 0.4% [12/2,828]) in early MDA villages and by 29% (from 7.2% [246/3,405] to 5.1% [155/3,057]) in control villages. Over the following 9 months, the P. falciparum prevalence increased to 3.3% (96/2,881) in early MDA villages and to 6.1% (128/2,101) in control villages (adjusted incidence rate ratio 0.41 [95% CI 0.20 to 0.84]; p = 0.015). Individual protection was proportional to the number of completed MDA rounds. Of 221 participants with subclinical P. falciparum infections who participated in MDA and could be followed up, 207 (94%) cleared their infections, including 9 of 10 with artemisinin- and piperaquine-resistant infections. The DP MDAs were well tolerated; 6 severe adverse events were detected during the follow-up period, but none was attributable to the intervention. CONCLUSIONS Added to community-based basic malaria control measures, 3 monthly rounds of DP MDA reduced the incidence and prevalence of falciparum malaria over a 1-year period in areas affected by artemisinin resistance. P. falciparum infections returned during the follow-up period as the remaining infections spread and malaria was reintroduced from surrounding areas. Limitations of this study include a relatively small sample of villages, heterogeneity between villages, and mobility of villagers that may have limited the impact of the intervention. These results suggest that, if used as part of a comprehensive, well-organised, and well-resourced elimination programme, DP MDA can be a useful additional tool to accelerate malaria elimination. TRIAL REGISTRATION ClinicalTrials.gov NCT01872702.
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Affiliation(s)
- Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Thomas J. Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jordi Landier
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Institut de Recherche pour le Développement, Aix–Marseille University, INSERM, SESSTIM, Marseille, France
| | - Thuy-Nhien Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Koukeo Phommasone
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Savannakhet Province, Lao People’s Democratic Republic
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Lilly Keereecharoen
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - May Myo Thwin
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Daniel M. Parker
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Department of Population Health and Disease Prevention, University of California, Irvine, Irvine, California, United States of America
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Suphak Nosten
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Stephane Proux
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Vincent Corbel
- Maladies Infectieuses et Vecteurs: Écologie, Génétique, Evolution et Contrôle, Institut de Recherche pour le Développement, Université Montpellier, Montpellier, France
| | - Nguyen Tuong-Vy
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Truong Le Phuc-Nhi
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Do Hung Son
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Pham Nguyen Huong-Thu
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Kim Tuyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nguyen Thanh Tien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Le Thanh Dong
- Institute of Malariology, Parasitology, and Entomology, Ho Chi Minh City, Vietnam
| | - Dao Van Hue
- Center for Malariology, Parasitology and Entomology, Ninh Thuan Province, Vietnam
| | - Huynh Hong Quang
- Institute of Malariology, Parasitology, and Entomology, Quy Nhon, Vietnam
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Huy Rekol
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Gisela Henriques
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Panom Phongmany
- Savannakhet Provincial Health Department, Savannakhet Province, Lao People’s Democratic Republic
| | - Preyanan Suangkanarat
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Atthanee Jeeyapant
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Benchawan Vihokhern
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rob W. van der Pluijm
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Yoel Lubell
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lisa J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Ricardo Aguas
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Cholrawee Promnarate
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand
| | - Pasathorn Sirithiranont
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Benoit Malleret
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Laurent Rénia
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore
| | - Carl Onsjö
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Faculty of Medicine and Health Sciences, Linköping University, Linköping, Linköping, Sweden
| | - Xin Hui Chan
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jeremy Chalk
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Olivo Miotto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Krittaya Patumrat
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kesinee Chotivanich
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Borimas Hanboonkunupakarn
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Podjanee Jittmala
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nils Kaehler
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Christopher Pell
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | - Mehul Dhorda
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Georges Snounou
- CEA–Université Paris Sud 11–INSERM U1184, IDMIT, Direction de la Recherche Fondamentale, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Pimnara Peerawaranun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sue J. Lee
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Sasithon Pukrittayakamee
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Royal Society of Thailand, Bangkok, Thailand
| | - Pratap Singhasivanon
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Martin P. Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Frank Cobelens
- Amsterdam Institute for Global Health & Development, Amsterdam, The Netherlands
| | | | - Paul N. Newton
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Guy E. Thwaites
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programmes, Ho Chi Minh City, Vietnam
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mayfong Mayxay
- Lao–Oxford–Mahosot Hospital–Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Lao People’s Democratic Republic
| | - Tran Tinh Hien
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Institut de Recherche pour le Développement, Aix–Marseille University, INSERM, SESSTIM, Marseille, France
| | - Francois H. Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Nofal SD, Peto TJ, Adhikari B, Tripura R, Callery J, Bui TM, von Seidlein L, Pell C. How can interventions that target forest-goers be tailored to accelerate malaria elimination in the Greater Mekong Subregion? A systematic review of the qualitative literature. Malar J 2019; 18:32. [PMID: 30709399 PMCID: PMC6359845 DOI: 10.1186/s12936-019-2666-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/27/2019] [Indexed: 11/26/2022] Open
Abstract
Background Despite decreases in incidence and related mortality, malaria remains a major public health challenge in the Greater Mekong Sub-region (GMS). The emergence of artemisinin resistance threatens these gains and has prompted efforts to accelerate elimination in the region. In the GMS, transmission now clusters in hotspots along international borders and among high-risk populations, including forest-goers. To eliminate malaria in the region, interventions must target such hard-to-reach populations. This review provides a comprehensive overview of the qualitative research on behaviours and perceptions that influence uptake of and adherence to malaria interventions among forest-goers in the GMS. Methods A systematic search strategy was used to identify relevant sources, including database (OVID SP, PubMed, ISI Web of Knowledge) and bibliographic searches. Relevant findings from qualitative research methods were extracted and thematic analysis undertaken. Results Of 268 sources retrieved in searches twenty-two were reviewed. Most reported studies were conducted in Cambodia (n = 10), and were published after 2014 (n = 16). Four major themes emerged that are particularly relevant to the design of intervention packages targeted at forest-goers: (1) understanding of malaria and perceived risk; (2) preventive measures used when visiting the forest; (3) behaviours that put forest-goers at risk of infection; and, (4) malaria-related treatment seeking. There were notable differences across the reviewed articles that suggest the need for a locally tailored approach. Conclusion A more detailed characterization of forest activities is needed but research on this topic raises methodological challenges. Current vector control measures have limitations, with use of insecticidal-treated nets, hammocks and repellents influenced by the type of forest activities and the characteristics of these measures. In contrast, anti-malarial drugs, for example, as chemoprophylaxis, hold promise but require further evaluation. Electronic supplementary material The online version of this article (10.1186/s12936-019-2666-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Bipin Adhikari
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - James Callery
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thanh Mai Bui
- Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christopher Pell
- Centre for Social Sciences and Global Health, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
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Iwagami M, Nakatsu M, Khattignavong P, Soundala P, Keomalaphet S, Lorpachan L, Xangsayalath P, Matsumoto-Takahashi E, Pommelet V, Hongvanthong B, Brey PT, Kano S. Heterogeneous distribution of k13 mutations in Plasmodium falciparum in Laos. Malar J 2018; 17:483. [PMID: 30587196 PMCID: PMC6307170 DOI: 10.1186/s12936-018-2625-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/11/2018] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The emergence and transnational spread of artemisinin resistance in Plasmodium falciparum in the Greater Mekong Sub-region (GMS) is a serious threat to malaria elimination in the region and could present a threat to malaria control in Africa. Recently, the Lao Government adopted the goal of malaria elimination by 2030, for which monitoring of artemisinin-resistant malaria within the country is indispensable. This study's objectives were to assess the distribution of k13 mutations in Laos. METHODS Plasmodium falciparum isolates (n = 1151) were collected from five southern provinces in Laos between 2015 and 2016, and three isolates from the northernmost province bordering China in 2017. Polymorphisms of the k13 gene and two flanking regions were analysed to estimate relationship among the isolates. RESULTS In the five southern provinces, overall 55.5% of the isolates possessed artemisinin-resistant mutations of the k13 gene (C580Y, P574L, R539T, Y493H). The C580Y was the predominant mutation (87.2%). The frequencies of the k13 mutations were heterogeneous in the five southern provinces, but with a clear tendency showing the highest frequency in the south (72.5%) and to a lower degree when moving northward (28.0%). The three isolates from the Lao-Chinese border also possessed the C580Y mutation. Analysis of the flanking loci demonstrated that these three isolates were genetically very close to resistant strains originating from western Cambodia. CONCLUSIONS Artemisinin resistance was observed to be rapidly increasing and spreading northwards through Laos and has now reached the Chinese border. The Lao and Chinese governments, as well as the international community, should make dedicated efforts to contain the spread of k13 mutations within Laos and in the GMS.
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Affiliation(s)
- Moritoshi Iwagami
- Department of Tropical Medicine and Malaria, Research Institute, National Centre for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655, Japan.,SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Masami Nakatsu
- Department of Tropical Medicine and Malaria, Research Institute, National Centre for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655, Japan.,SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic
| | - Phonepadith Khattignavong
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Pheovaly Soundala
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Sengdeuane Keomalaphet
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Lavy Lorpachan
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Phonepadith Xangsayalath
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,National Institute of Public Health, Ministry of Health, Vientiane, Lao People's Democratic Republic
| | - Emilie Matsumoto-Takahashi
- Department of Tropical Medicine and Malaria, Research Institute, National Centre for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655, Japan.,SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic
| | - Virginie Pommelet
- Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic
| | - Bouasy Hongvanthong
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic.,Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Lao People's Democratic Republic
| | - Paul T Brey
- SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic. .,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic.
| | - Shigeyuki Kano
- Department of Tropical Medicine and Malaria, Research Institute, National Centre for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo, 162-8655, Japan. .,SATREPS Project (JICA/AMED) for Parasitic Diseases, Vientiane, Lao People's Democratic Republic. .,Institut Pasteur du Laos, Ministry of Health, Sansenthai Road, Ban Kao-Gnot, Sisattanak District, P.O. Box 3560, Vientiane, Lao People's Democratic Republic.
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Peto TJ, Tripura R, Davoeung C, Nguon C, Nou S, Heng C, Kunthea P, Adhikari B, Lim R, James N, Pell C, Cheah PY. Reflections on a Community Engagement Strategy for Mass Antimalarial Drug Administration in Cambodia. Am J Trop Med Hyg 2018; 98:100-104. [PMID: 29165227 PMCID: PMC5928715 DOI: 10.4269/ajtmh.17-0428] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mass drug administration (MDA) to interrupt malaria transmission requires the participation of entire communities. As part of a clinical trial in western Cambodia, four villages received MDA in 2015–2016. Before approaching study communities, a collaboration was established with the local health authorities, village leaders, and village malaria workers. Formative research guided the development of engagement strategies. In each village, a team of volunteers was formed to explain MDA to their neighbors and provide support during implementation. Public mobilization events featuring drama and music were used to introduce MDA. Villages comprised groups with different levels of understanding and interests; therefore, multiple tailored engagement strategies were required. The main challenges were explaining malaria transmission, managing perceptions of drug side effects, and reaching mobile populations. It was important that local leaders took a central role in community engagement. Coverage during each round of MDA averaged 84%, which met the target for the trial.
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Affiliation(s)
- Thomas J Peto
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chan Davoeung
- Department of Provincial Health, Battambang, Cambodia
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Sanann Nou
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chhouen Heng
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pich Kunthea
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Bipin Adhikari
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Renly Lim
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Nicola James
- Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher Pell
- Centre for Social Science and Global Health, University of Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
| | - Phaik Yeong Cheah
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,The Ethox Centre, University of Oxford, Oxford, United Kingdom
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30
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Sattabongkot J, Suansomjit C, Nguitragool W, Sirichaisinthop J, Warit S, Tiensuwan M, Buates S. Prevalence of asymptomatic Plasmodium infections with sub-microscopic parasite densities in the northwestern border of Thailand: a potential threat to malaria elimination. Malar J 2018; 17:329. [PMID: 30208895 PMCID: PMC6134695 DOI: 10.1186/s12936-018-2476-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/04/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Asymptomatic infections with sub-microscopic Plasmodium serve as a silent reservoir of disease, critical to sustaining a low level of remanent malaria in the population. These infections must be effectively identified and targeted for elimination. The sensitivity of light microscopy, the traditional method used for diagnosing Plasmodium infections, is frequently insufficient for detecting asymptomatic infections due to the low density of parasitaemia. The objective of this study was to explore the current prevalence of asymptomatic sub-microscopic Plasmodium carriages to evaluate the parasite reservoir amongst residents from 7 hamlets in Tak Province in northwestern Thailand using a highly sensitive molecular method. METHODS Malaria infection was screened in a real-world setting from 3650 finger-prick blood specimens collected in a mass cross-sectional survey using light microscopy and loop-mediated isothermal amplification (LAMP). LAMP results were later confirmed in a laboratory setting in Bangkok using nested PCR, restriction enzyme digestion and DNA sequencing. The association of malaria infection with demographic factors was explored. RESULTS Parasite prevalence was 0.27% (10/3650) as determined by microscopy. Sub-microscopic infection prevalence was 2.33% (85/3650) by LAMP. Of these, 30.6% (26/85) were infected with Plasmodium falciparum, 52.9% (45/85) with Plasmodium vivax, 2.4% (2/85) with Plasmodium malariae, 4.7% (4/85) with mixed P. falciparum and P. vivax, and 9.4% (8/85) had parasite densities too low for species identification. Asymptomatic carriages (T < 37.5 °C) accounted for 95% (76/80) of all sub-microscopic cases with the highest prevalence occurring in the subjects 31-45 years of age (p ≤ 0.035). Participants working on plantations or as merchants had an increased infection risk. Evaluation by microscopy identified 10.53% (10/95) of all Plasmodium infected participants. CONCLUSION Participants carrying asymptomatic Plasmodium infections with sub-microscopic parasite densities are considerable in this area. These findings provide the true disease burden and risk factors in this region. This information helps to direct policy makers towards better schemes and delivery of targeted interventions. Moreover, this is the first study to use LAMP in mass screening for sub-clinical and sub-microscopic infections in a field setting in Thailand. LAMP proves to be a sensitive and field-deployable assay suitable for national malaria control screening campaigns.
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Affiliation(s)
- Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chayanut Suansomjit
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Saradee Warit
- Tuberculosis Research Laboratory, Medical Molecular Biology Research Unit, BIOTEC, National Science and Technology Development Agency, Thailand Science Park, Pathum Thani, Thailand
| | - Montip Tiensuwan
- Department of Mathematics, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sureemas Buates
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
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31
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Willie N, Zimmerman PA, Mehlotra RK. Plasmodium falciparum Histidine-Rich Protein 2 Gene Variation in a Malaria-Endemic Area of Papua New Guinea. Am J Trop Med Hyg 2018; 99:697-703. [PMID: 29968556 DOI: 10.4269/ajtmh.18-0137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Histidine-rich protein 2 of Plasmodium falciparum (PfHRP2) forms the basis of many current malaria rapid diagnostic tests (RDTs). It is concerning that there are parasites that lack part or all of the pfhrp2 gene, and thus do not express the PfHRP2 protein; such parasites are not identifiable by PfHRP2-detecting RDTs. Very limited information is available regarding pfhrp2 genetic variation in Papua New Guinea (PNG). In the present study, this gene variation was evaluated using 169 samples previously collected from the Wosera area in East Sepik Province of PNG. Molecular diagnosis of these samples showed that 81% were infected, and P. falciparum was present in 91% of those infected samples. One hundred and twenty samples were amplified for pfhrp2 exon-2, from which 12 randomly selected amplicons were sequenced, yielding 18 sequences, all of which were unique. Baker repeat type 2 × type 7 numbers ranged from 0 to 108. Epitope mapping analysis revealed that three major epitopes, DAHHAHHA, AHHAADAHHA, and AHHAADAHH, were present in high prevalence and frequencies. These major epitopes have been shown to be recognized by the monoclonal antibodies 3A4 and PTL-3 (DAHHAHHA), C1-13 (AHHAADAHHA), and S2-5 and C2-3 (AHHAADAHH). This study provides further information on the high genetic variation of pfhrp2 and its unclear relationship with prediction of RDT detection sensitivity, and identifies major epitopes in this gene from PNG. These results could be relevant and useful to understand the genetic diversity of this gene and the performance of current and future RDTs in this malarious region of the world.
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Affiliation(s)
- Nigani Willie
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Peter A Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Rajeev K Mehlotra
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio
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32
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Landier J, Parker DM, Thu AM, Lwin KM, Delmas G, Nosten FH. Effect of generalised access to early diagnosis and treatment and targeted mass drug administration on Plasmodium falciparum malaria in Eastern Myanmar: an observational study of a regional elimination programme. Lancet 2018; 391:1916-1926. [PMID: 29703425 PMCID: PMC5946089 DOI: 10.1016/s0140-6736(18)30792-x] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Potentially untreatable Plasmodium falciparum malaria threatens the Greater Mekong subregion. A previous series of pilot projects in Myanmar, Laos, Cambodia, and Vietnam suggested that mass drug administration was safe, and when added to provision of early diagnosis and treatment, could reduce the reservoir of P falciparum and interrupts transmission. We examined the effects of a scaled-up programme of this strategy in four townships of eastern Myanmar on the incidence of P falciparum malaria. METHODS The programme was implemented in the four townships of Myawaddy, Kawkareik, Hlaingbwe, and Hpapun in Kayin state, Myanmar. Increased access to early diagnosis and treatment of malaria was provided to all villages through community-based malaria posts equipped with rapid diagnostic tests, and treatment with artemether-lumefantrine plus single low-dose primaquine. Villages were identified as malarial hotspots (operationally defined as >40% malaria, of which 20% was P falciparum) with surveys using ultrasensitive quantitative PCR either randomly or targeted at villages where the incidence of clinical cases of P falciparum malaria remained high (ie, >100 cases per 1000 individuals per year) despite a functioning malaria post. During each survey, a 2 mL sample of venous blood was obtained from randomly selected adults. Hotspots received targeted mass drug administration with dihydroartemisinin-piperaquine plus single-dose primaquine once per month for 3 consecutive months in addition to the malaria posts. The main outcome was the change in village incidence of clinical P falciparum malaria, quantified using a multivariate, generalised, additive multilevel model. Malaria prevalence was measured in the hotspots 12 months after mass drug administration. FINDINGS Between May 1, 2014, and April 30, 2017, 1222 malarial posts were opened, providing early diagnosis and treatment to an estimated 365 000 individuals. Incidence of P falciparum malaria decreased by 60 to 98% in the four townships. 272 prevalence surveys were undertaken and 69 hotspot villages were identified. By April 2017, 50 hotspots were treated with mass drug administration. Hotspot villages had a three times higher incidence of P falciparum at malarial posts than neighbouring villages (adjusted incidence rate ratio [IRR] 2·7, 95% CI 1·8-4·4). Early diagnosis and treatment was associated with a significant decrease in P falciparum incidence in hotspots (IRR 0·82, 95% CI 0·76-0·88 per quarter) and in other villages (0·75, 0·73-0·78 per quarter). Mass drug administration was associated with a five-times decrease in P falciparum incidence within hotspot villages (IRR 0·19, 95% CI 0·13-0·26). By April, 2017, 965 villages (79%) of 1222 corresponding to 104 village tracts were free from P falciparum malaria for at least 6 months. The prevalence of wild-type genotype for K13 molecular markers of artemisinin resistance was stable over the three years (39%; 249/631). INTERPRETATION Providing early diagnosis and effective treatment substantially decreased village-level incidence of artemisinin-resistant P falciparum malaria in hard-to-reach, politically sensitive regions of eastern Myanmar. Targeted mass drug administration significantly reduced malaria incidence in hotspots. If these activities could proceed in all contiguous endemic areas in addition to standard control programmes already implemented, there is a possibility of subnational elimination of P falciparum. FUNDING The Bill & Melinda Gates Foundation, the Regional Artemisinin Initiative (Global Fund against AIDS, Tuberculosis and Malaria), and the Wellcome Trust.
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Affiliation(s)
- Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Institut de Recherches pour le Développement, Aix Marseille Univ, INSERM, SESSTIM, Sciences Economiques & Sociales de la Santé & Traitement de l'Information Médicale, Marseille, France.
| | - Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Department of Population Health and Disease Prevention, University of California, Irvine, CA, USA
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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33
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Taffon P, Rossi G, Kindermans JM, Van den Bergh R, Nguon C, Debackere M, Vernaeve L, De Smet M, Venables E. 'I could not join because I had to work for pay.': A qualitative evaluation of falciparum malaria pro-active case detection in three rural Cambodian villages. PLoS One 2018; 13:e0195809. [PMID: 29649317 PMCID: PMC5897025 DOI: 10.1371/journal.pone.0195809] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 03/29/2018] [Indexed: 11/19/2022] Open
Abstract
Background Pro-active case detection (Pro-ACD), in the form of voluntary screening and treatment (VSAT) following community mobilisation about ‘asymptomatic malaria’, is currently being evaluated as a tool for Plasmodium falciparum elimination in Preah Vihear Province, Cambodia. Methods A qualitative study was conducted to explore community understanding, perceptions, expectations and acceptability of the Pro-ACD intervention in order to identify aspects that could be improved in future Pro-ACD activities. This was ancillary to a three-round VSAT campaign, carried out in three villages between December 2015 and March 2016. Qualitative data collection began shortly after the end of the three rounds of screening. Purposive sampling was used to select participants. Nine focus group discussions with participants (n = 46) and non-participants (n = 40) in the Pro-ACD screening were conducted, in addition to in-depth interviews with key village figures (n = 9). Results Health promotion messages were well delivered and received, but it was difficult for many villagers to understand the messages around ‘asymptomatic malaria’. Overall, villagers and village leaders had a positive opinion about the VSAT intervention. Acceptability was high, as a direct consequence of favourable perceptions towards the screening activity: the Pro-ACD intervention was seen by the local population as an effective, inexpensive, reliable and readily available tool to protect individuals and the community from the insurgence of malaria. Physical absence and lack of time (both linked to work-related activities) were the main reasons for non-participation. Conclusions Although VSAT was generally well perceived and accepted, the ‘time factor’ related to the need to satisfy essential daily subsistence requirements played a significant role in determining participation in the screening. More well-adapted and meaningful Pro-ACD approaches could be implemented by improving the timing of the testing activites, and strengthening community participation and engagement to increase acceptability.
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Affiliation(s)
| | | | | | | | - Chea Nguon
- Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | | | - Martin De Smet
- Médecins Sans Frontières, Operational Centre Belgium, Brussels, Belgium
| | - Emilie Venables
- Médecins Sans Frontières, Operational Centre Belgium, Brussels, Belgium
- Division of Social and Behavioural Sciences, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
- * E-mail:
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34
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Peto TJ, Debackere M, Etienne W, Vernaeve L, Tripura R, Falq G, Davoeung C, Nguon C, Rekol H, von Seidlein L, Dondorp AM, Sanann N, Cheah PY, De Smet M, Pell C, Kindermans JM. Community participation during two mass anti-malarial administrations in Cambodia: lessons from a joint workshop. Malar J 2018; 17:53. [PMID: 29374462 PMCID: PMC5787251 DOI: 10.1186/s12936-018-2202-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/20/2018] [Indexed: 11/16/2022] Open
Abstract
Two mass drug administrations (MDA) against falciparum malaria were conducted in 2015–16, one as operational research in northern Cambodia, and the other as a clinical trial in western Cambodia. During an April 2017 workshop in Phnom Penh the field teams from Médecins Sans Frontières and the Mahidol-Oxford Tropical Medicine Research Unit discussed lessons for future MDAs.
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Affiliation(s)
- Thomas J Peto
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | | | | | | | - Rupam Tripura
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | - Chea Nguon
- Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Huy Rekol
- Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Lorenz von Seidlein
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nou Sanann
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phaik Yeong Cheah
- Mahidol-Oxford University Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - Christopher Pell
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
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35
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Durnez L, Pareyn M, Mean V, Kim S, Khim N, Menard D, Coosemans M, Sochantha T, Sluydts V. Identification and characterization of areas of high and low risk for asymptomatic malaria infections at sub-village level in Ratanakiri, Cambodia. Malar J 2018; 17:27. [PMID: 29334956 PMCID: PMC5769347 DOI: 10.1186/s12936-017-2169-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 12/29/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Malaria elimination needs a concentration of activities towards identification of residual transmission foci and intensification of efforts to eliminate the last few infections, located in so-called 'malaria hotspots'. Previous work on characterizing malaria transmission hotspots has mainly focused on falciparum malaria and especially on symptomatic cases, while the malaria reservoir is expected to be mainly concentrated in the asymptomatic human population when transmission is low. For Plasmodium vivax, there has been less effort in identifying transmission hotspots. The main aim of this study was to uncover micro-epidemiological mechanisms of clustering of malaria infections at a sub-village level, based on geographical or behavioural features. METHODS A cross-sectional survey was performed in three villages within the highest malaria endemic province of Cambodia. The survey took place in the dry season, when the malaria reservoir is expected to be low and residing in the asymptomatic part of the population. Village and field locations of households were georeferenced, blood samples were taken from as many residents as possible and a short questionnaire probing for individual risk factors was taken. Asymptomatic malaria carriers were detected by PCR, and geographical clustering analysis (SaTScan) as well as risk factor analysis were performed. RESULTS A total of 1540 out of 1792 (86%) individuals were sampled. Plasmodial DNA was detected in 129 individuals (8.4%). P. vivax was most prevalent (5.5%) followed by Plasmodium malariae (2.1%) and Plasmodium falciparum (1.6%). Mixed infection occurred in 12 individuals. In two out of three villages geographical clustering of high and low malaria infection risk was clearly present. Cluster location and risk factors associated with the infection differed between the parasite species. Age was an important risk factor for the combined Plasmodium infections, while watching television at evenings was associated with increased odds of P. vivax infections [OR (CI): 1.86 (0.95-3.64)] and bed net use was associated with reduced odds of P. falciparum infections [OR (CI): 0.25 (0.077-0.80)]. CONCLUSIONS Clusters of malaria carriers were malaria species specific and often located remotely, outside village centres. As such, at micro-epidemiological level, malaria is not a single disease. Further unravelling the micro-epidemiology of malaria can enable programme managers to define the interventions likely to contribute to halt transmission in a particular hotspot location.
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Affiliation(s)
- Lies Durnez
- Institute of Tropical Medicine, Antwerp, Belgium. .,University of Antwerp, Antwerp, Belgium.
| | - Myrthe Pareyn
- Institute of Tropical Medicine, Antwerp, Belgium.,University of Antwerp, Antwerp, Belgium
| | - Vanna Mean
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Saorin Kim
- Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Nimol Khim
- Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | | | - Marc Coosemans
- Institute of Tropical Medicine, Antwerp, Belgium.,University of Antwerp, Antwerp, Belgium
| | - Tho Sochantha
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Vincent Sluydts
- Institute of Tropical Medicine, Antwerp, Belgium. .,University of Antwerp, Antwerp, Belgium.
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36
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Adhikari B, Phommasone K, Kommarasy P, Soundala X, Souvanthong P, Pongvongsa T, Henriques G, Newton PN, White NJ, Day NPJ, Dondorp AM, von Seidlein L, Mayxay M, Cheah PY, Pell C. Why do people participate in mass anti-malarial administration? Findings from a qualitative study in Nong District, Savannakhet Province, Lao PDR (Laos). Malar J 2018; 17:15. [PMID: 29316932 PMCID: PMC5761145 DOI: 10.1186/s12936-017-2158-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 12/23/2017] [Indexed: 01/01/2023] Open
Abstract
Background As a part of targeted malaria elimination (TME) in the Greater Mekong Sub-region (GMS), mass drug administration (MDA) with anti-malarials was conducted in four villages in Nong District, Savannakhet Province, Lao PDR (Laos). A high proportion of the target population participated in the MDA, with over 87% agreeing to take the anti-malarial. Drawing on qualitative data collected alongside the MDA, this article explores the factors that led to this high population coverage. Methods Qualitative data collection methods included observations, which were recorded in field notes, focus group discussions (FGDs), and semi-structured interviews (SSIs). Data were collected on local context, MDA-related knowledge, attitudes and perceptions. FGDs and SSIs were audio-recorded, transcribed and translated to English. All transcriptions and field notes underwent qualitative content analysis using QSR NVivo. Results Respondents recognized malaria as a health concern and described the need for a malaria control program. The risk of malaria including asymptomatic infection was explained in terms of participants’ work in forest and fields, and poor hygiene. During the MDA rounds, there was an improvement in knowledge on the concept of asymptomatic malaria, the rationale of MDA and the blood test. In all four villages, poverty affected access to healthcare and the provision of free care by TME was highly appreciated. TME was jointly undertaken by research staff and local volunteers. Authorities were involved in all TME activities. Lao Theung communities were cohesive and community members tended to follow each other’s behaviour closely including participation in MDA. Factors such as understanding the concept and rationale of the study, free health care, collaboration with the village volunteers, support from authorities and cohesive communities contributed in building trust and high population coverage in MDA. Conclusion Future malaria control programmes can become successful in achieving the high coverage in MDAs drawing from the success of TME in Laos. A high population coverage in TME was a combination of various factors that included the community engagement to promote the concept and rationale of MDA for asymptomatic malaria in addition to their baseline understanding of malaria as a health concern, provision of free primary health care, partnering of the research with local volunteers and authorities, building social relationship with community members and the cohesive nature of the communities boosted the trust and participation in MDA. Electronic supplementary material The online version of this article (10.1186/s12936-017-2158-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bipin Adhikari
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.,Kellogg College, University of Oxford, Oxford, UK
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos
| | - Palingnaphone Kommarasy
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos
| | - Xayaphone Soundala
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos
| | - Phonesavanh Souvanthong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Savannakhet, Savannakhet Province, Laos
| | - Gisela Henriques
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Laos.,Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Laos
| | - Phaik Yeong Cheah
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK. .,The Ethox Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
| | - Christopher Pell
- Centre for Social Science and Global Health, University of Amsterdam, Amsterdam, The Netherlands.,Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands
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Mogeni P, Williams TN, Omedo I, Kimani D, Ngoi JM, Mwacharo J, Morter R, Nyundo C, Wambua J, Nyangweso G, Kapulu M, Fegan G, Bejon P. Detecting Malaria Hotspots: A Comparison of Rapid Diagnostic Test, Microscopy, and Polymerase Chain Reaction. J Infect Dis 2017; 216:1091-1098. [PMID: 28973672 PMCID: PMC5853881 DOI: 10.1093/infdis/jix321] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/06/2017] [Indexed: 12/21/2022] Open
Abstract
Background Malaria control strategies need to respond to geographical hotspots of transmission. Detection of hotspots depends on the sensitivity of the diagnostic tool used. Methods We conducted cross-sectional surveys in 3 sites within Kilifi County, Kenya, that had variable transmission intensities. Rapid diagnostic test (RDT), microscopy, and polymerase chain reaction (PCR) were used to detect asymptomatic parasitemia, and hotspots were detected using the spatial scan statistic. Results Eight thousand five hundred eighty-one study participants were surveyed in 3 sites. There were statistically significant malaria hotspots by RDT, microscopy, and PCR for all sites except by microscopy in 1 low transmission site. Pooled data analysis of hotspots by PCR overlapped with hotspots by microscopy at a moderate setting but not at 2 lower transmission settings. However, variations in degree of overlap were noted when data were analyzed by year. Hotspots by RDT were predictive of PCR/microscopy at the moderate setting, but not at the 2 low transmission settings. We observed long-term stability of hotspots by PCR and microscopy but not RDT. Conclusion Malaria control programs may consider PCR testing to guide asymptomatic malaria hotspot detection once the prevalence of infection falls.
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Affiliation(s)
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Faculty of Medicine, Imperial College London
| | - Irene Omedo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Joyce M Ngoi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Richard Morter
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,The Jenner Institute, Nuffield Department of Medicine, University of Oxford
| | | | | | | | - Melissa Kapulu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford
| | - Gregory Fegan
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Swansea Trials Unit, Swansea University Medical School, Swansea, United Kingdom
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford
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Tun STT, von Seidlein L, Pongvongsa T, Mayxay M, Saralamba S, Kyaw SS, Chanthavilay P, Celhay O, Nguyen TD, Tran TNA, Parker DM, Boni MF, Dondorp AM, White LJ. Towards malaria elimination in Savannakhet, Lao PDR: mathematical modelling driven strategy design. Malar J 2017; 16:483. [PMID: 29183370 PMCID: PMC5706414 DOI: 10.1186/s12936-017-2130-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The number of Plasmodium falciparum malaria cases around the world has decreased substantially over the last 15 years, but with the spread of resistance against anti-malarial drugs and insecticides, this decline may not continue. There is an urgent need to consider alternative, accelerated strategies to eliminate malaria in countries like Lao PDR, where there are a few remaining endemic areas. A deterministic compartmental modelling tool was used to develop an integrated strategy for P. falciparum elimination in the Savannakhet province of Lao PDR. The model was designed to include key aspects of malaria transmission and integrated control measures, along with a user-friendly interface. RESULTS Universal coverage was the foundation of the integrated strategy, which took the form of the deployment of community health workers who provided universal access to early diagnosis, treatment and long-lasting insecticidal nets. Acceleration was included as the deployment of three monthly rounds of mass drug administration targeted towards high prevalence villages, with the addition of three monthly doses of the RTS,S vaccine delivered en masse to the same high prevalence sub-population. A booster dose of vaccine was added 1 year later. The surveillance-as-intervention component of the package involved the screening and treatment of individuals entering the simulated population. CONCLUSIONS In this modelling approach, the sequential introduction of a series of five available interventions in an integrated strategy was predicted to be sufficient to stop malaria transmission within a 3-year period. These interventions comprised universal access to early diagnosis and adequate treatment, improved access to long-lasting insecticidal nets, three monthly rounds of mass drug administration together with RTS,S vaccination followed by a booster dose of vaccine, and screening and treatment of imported cases.
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Affiliation(s)
- Sai Thein Than Tun
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Health Department, Phonsavangnuea Village, Kaysone-Phomvihan District, Savannakhet, Lao People's Democratic Republic
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Vientiane, Lao People's Democratic Republic.,Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People's Democratic Republic
| | - Sompob Saralamba
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Shwe Sin Kyaw
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phetsavanh Chanthavilay
- Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People's Democratic Republic.,Institute of Francophonie for Tropical Medicine, Vientiane, Lao People's Democratic Republic
| | - Olivier Celhay
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tran Dang Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Thu Nguyen-Anh Tran
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
| | - Maciej F Boni
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK.,Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
| | - Lisa J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK
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