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Getachew H, Demissew A, Abossie A, Habtamu K, Wang X, Zhong D, Zhou G, Lee MC, Hemming-Schroeder E, Bradley L, Degefa T, Hawaria D, Tsegaye A, W Kazura J, Koepfli C, Yan G, Yewhalaw D. Asymptomatic and submicroscopic malaria infections in sugar cane and rice development areas of Ethiopia. Malar J 2023; 22:341. [PMID: 37940948 PMCID: PMC10634149 DOI: 10.1186/s12936-023-04762-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 10/22/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Water resource development projects, such as dams and irrigation schemes, have a positive impact on food security and poverty reduction. However, such projects could increase prevalence of vector borne disease, such as malaria. This study investigate the impact of different agroecosystems and prevalence of malaria infection in Southwest Ethiopia. METHODS Two cross-sectional surveys were conducted in the dry and wet seasons in irrigated and non-irrigated clusters of Arjo sugarcane and Gambella rice development areas of Ethiopia in 2019. A total of 4464 and 2176 study participants from 1449 households in Arjo and 546 households in Gambella enrolled in the study and blood samples were collected, respectively. All blood samples were microscopically examined and a subset of microscopy negative blood samples (n = 2244) were analysed by qPCR. Mixed effect logistic regression and generalized estimating equation were used to determine microscopic and submicroscopic malaria infection and the associated risk factors, respectively. RESULTS Prevalence by microscopy was 2.0% (88/4464) in Arjo and 6.1% (133/2176) in Gambella. In Gambella, prevalence was significantly higher in irrigated clusters (10.4% vs 3.6%) than in non-irrigated clusters (p < 0.001), but no difference was found in Arjo (2.0% vs 2.0%; p = 0.993). On the other hand, of the 1713 and 531 samples analysed by qPCR from Arjo and Gambella the presence of submicroscopic infection was 1.2% and 12.8%, respectively. Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale were identified by qPCR in both sites. Irrigation was a risk factor for submicroscopic infection in both Arjo and Gambella. Irrigation, being a migrant worker, outdoor job, < 6 months length of stay in the area were risk factors for microscopic infection in Gambella. Moreover, school-age children and length of stay in the area for 1-3 years were significant predictors for submicroscopic malaria in Gambella. However, no ITN utilization was a predictor for both submicroscopic and microscopic infection in Arjo. Season was also a risk factor for microscopic infection in Arjo. CONCLUSION The study highlighted the potential importance of different irrigation practices impacting on submicroscopic malaria transmission. Moreover, microscopic and submicroscopic infections coupled with population movement may contribute to residual malaria transmission and could hinder malaria control and elimination programmes in the country. Therefore, strengthening malaria surveillance and control by using highly sensitive diagnostic tools to detect low-density parasites, screening migrant workers upon arrival and departure, ensuring adequate coverage and proper utilization of vector control tools, and health education for at-risk groups residing or working in such development corridors is needed.
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Affiliation(s)
- Hallelujah Getachew
- Department of Medical Laboratory Technology, Arbaminch College of Health Sciences, Arbaminch, Ethiopia.
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Ashenafi Abossie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Arbaminch University, Arbaminch, Ethiopia
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Kassahun Habtamu
- Menelik II Medical & Health Science College, Addis Ababa, Ethiopia
- Department of Microbial, Cellular & Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Elizabeth Hemming-Schroeder
- Center for Vector Born Infectious Diseases (CVID), Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, USA
| | - Lauren Bradley
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Dawit Hawaria
- School of Environmental Health, Hawassa University, Hawassa, Ethiopia
| | - Arega Tsegaye
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - James W Kazura
- Biomedical Research Case Western Reserve University, Cleveland, OH, USA
- Center for Global Health & Disease School of Medicine Case, Western Reserve University, Cleveland, OH, USA
| | - Cristian Koepfli
- Department of Biological Sciences 319 Galvin Life Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
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Getachew H, Demissew A, Abossie A, Habtamu K, Wang X, Zhong D, Zhou G, Lee MC, Hemming-Schroeder E, Bradley L, Degefa T, Hawaria D, Tsegaye A, Kazura JW, Koepfli C, Yan G, Yewhalaw D. Asymptomatic and submicroscopic malaria infections in sugar cane and rice development areas of Ethiopia. RESEARCH SQUARE 2023:rs.3.rs-2692688. [PMID: 36993196 PMCID: PMC10055656 DOI: 10.21203/rs.3.rs-2692688/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Background Water resource development projects such as dams and irrigation schemes have a positive impact on food security and poverty reduction but might result in increased prevalence of malaria. Methods Two cross-sectional surveys were conducted in the dry and wet seasons in irrigated and non-irrigated clusters of Arjo sugarcane and Gambella rice development areas of Ethiopia in 2019. A total of 4464 and 2176 blood samples were collected from Arjo and Gambella. A subset of 2244 microscopy negative blood samples were analyzed by PCR. Results Prevalence by microscopy was 2.0% (88/4464) in Arjo and 6.1% (133/2176) in Gambella. In Gambella, prevalence was significantly higher in irrigated clusters (10.4% vs 3.6%) than in non-irrigated clusters (p < 0.001), but no difference was found in Arjo (2.0% vs 2.0%; p = 0.993). Level of education was an individual risk factors associated with infection in Arjo [AOR: 3.2; 95%CI (1.27-8.16)] and in Gambella [AOR: 1.7; 95%CI (1.06-2.82)]. While duration of stay in the area for < 6 months [AOR: 4.7; 95%CI (1.84-12.15)] and being a migrant worker [AOR: 4.7; 95%CI (3.01-7.17)] were risk factors in Gambella. Season [AOR: 15.9; 95%CI (6.01-42.04)], no ITN utilization [AOR: 22.3; 95%CI (7.74-64.34)] were risk factors in Arjo, and irrigation [AOR: 2.4; 95%CI (1.45-4.07)] and family size [AOR: 2.3; 95%CI (1.30-4.09)] risk factors in Gambella. Of the 1713 and 531 randomly selected smear negative samples from Arjo and Gambella and analyzed by PCR the presence of Plasmodium infection was 1.2% and 12.8%, respectively. P. falciparum, P. vivax, and P. ovale were identified by PCR in both sites. Conclusion Strengthening malaria surveillance and control in project development areas and proper health education for at-risk groups residing or working in such development corridors is needed.
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Affiliation(s)
- Hallelujah Getachew
- Department of Medical Laboratory Technology, Arbaminch College of Health Sciences, Arbaminch
| | - Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo
| | - Ashenafi Abossie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Arbaminch University, Arbaminch
| | | | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Elizabeth Hemming-Schroeder
- Center for Vector Born Infectious Diseases (CVID), Department of Microbiology Immunology and Pathology, Colorado State University
| | - Lauren Bradley
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma
| | - Dawit Hawaria
- Hawassa University, School of Environmental Health, Hawassa
| | - Arega Tsegaye
- Department of Biology, College of Natural Science, Jimma University
| | - James W Kazura
- Biomedical Research Case Western Reserve University, Cleveland, Ohio
| | - Cristian Koepfli
- Department of Biological Sciences 319 Galvin Life Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA 92697
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma
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Mwenda MC, Fola AA, Ciubotariu II, Mulube C, Mambwe B, Kasaro R, Hawela MB, Hamainza B, Miller JM, Carpi G, Bridges DJ. Performance evaluation of RDT, light microscopy, and PET-PCR for detecting Plasmodium falciparum malaria infections in the 2018 Zambia National Malaria Indicator Survey. Malar J 2021; 20:386. [PMID: 34583692 PMCID: PMC8477358 DOI: 10.1186/s12936-021-03917-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/14/2021] [Indexed: 11/29/2022] Open
Abstract
Background Zambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of Rapid Diagnostic Tests (RDT) and Light Microscopy (LM) with photo-induced electron transfer polymerase chain reaction (PET-PCR) as the gold standard using 2018 Malaria Indicator Survey (MIS) data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient. Methods Cross-sectional samples collected in a nationally representative survey from 7 provinces in Zambia were tested for the presence of malaria parasites by light microscopy (LM), rapid diagnostic test (RDT) and the gold standard PET-PCR. Diagnostic performance was assessed including sensitivity, specificity, negative- and positive-predictive values across a wide malaria transmission spectrum. Diagnostic accuracy metrics were measured, and statistically significant differences were calculated between test methods for different outcome variables. Results From the individuals included in the MIS, the overall prevalence of Plasmodium falciparum malaria was 32.9% by RDT, 19.4% by LM, and 23.2% by PET-PCR. Herein, RDT and LM diagnostic performance was compared against gold standard PET-PCR with LM displaying a higher diagnostic accuracy than RDTs (91.3% vs. 84.6% respectively) across the transmission spectrum in Zambia. However, the performance of both diagnostics was significantly reduced in low parasitaemia samples. Consistent with previous studies, RDT diagnostic accuracy was predominantly affected by a high rate of false positives. Conclusions RDTs and LM both perform well across a range of transmission intensities within their respective target applications, i.e., in the community, for the former, where ease of use and speed of result is critical, and at the health facility, for the latter, where accuracy is prioritized. However, the performance of both diagnostic methods is adversely affected by low parasitaemia infections. As Zambia moves towards elimination more sensitive tools may be required to identify the last cases. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03917-6.
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Affiliation(s)
- Mulenga C Mwenda
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Abebe A Fola
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Conceptor Mulube
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Brenda Mambwe
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Rachael Kasaro
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Moonga B Hawela
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - John M Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Indiana, USA
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia.
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Roberts KW, Smith Gueye C, Baltzell K, Ntuku H, McCreesh P, Maglior A, Whittemore B, Uusiku P, Mumbengegwi D, Kleinschmidt I, Gosling R, Hsiang MS. Community acceptance of reactive focal mass drug administration and reactive focal vector control using indoor residual spraying, a mixed-methods study in Zambezi region, Namibia. Malar J 2021; 20:162. [PMID: 33752673 PMCID: PMC7986500 DOI: 10.1186/s12936-021-03679-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Namibia, as in many malaria elimination settings, reactive case detection (RACD), or malaria testing and treatment around index cases, is a standard intervention. Reactive focal mass drug administration (rfMDA), or treatment without testing, and reactive focal vector control (RAVC) in the form of indoor residual spraying, are alternative or adjunctive interventions, but there are limited data regarding their community acceptability. METHODS A parent trial aimed to compare the effectiveness of rfMDA versus RACD, RAVC versus no RAVC, and rfMDA + RAVC versus RACD only. To assess acceptability of these interventions, a mixed-methods study was conducted using key informant interviews (KIIs) and focus group discussions (FGDs) in three rounds (pre-trial and in years 1 and 2 of the trial), and an endline survey. RESULTS In total, 17 KIIs, 49 FGDs were conducted with 449 people over three annual rounds of qualitative data collection. Pre-trial, community members more accurately predicted the level of community acceptability than key stakeholders. Throughout the trial, key participant motivators included: malaria risk perception, access to free community-based healthcare and IRS, and community education by respectful study teams. RACD or rfMDA were offered to 1372 and 8948 individuals in years 1 and 2, respectively, and refusal rates were low (< 2%). RAVC was offered to few households (n = 72) in year 1. In year 2, RAVC was offered to more households (n = 944) and refusals were < 1%. In the endline survey, 94.3% of 2147 respondents said they would participate in the same intervention again. CONCLUSIONS Communities found both reactive focal interventions and their combination highly acceptable. Engaging communities and centering and incorporating their perspectives and experiences during design, implementation, and evaluation of this community-based intervention was critical for optimizing study engagement.
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Affiliation(s)
- Kathryn W Roberts
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA.
- Global Programs for Research and Training, Malaria Elimination Initiative Namibia, Windhoek, Namibia.
| | - Cara Smith Gueye
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA
- Global Programs for Research and Training, Malaria Elimination Initiative Namibia, Windhoek, Namibia
| | - Kimberly Baltzell
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA
- Department of Family Health Care Nursing, School of Nursing, UCSF, San Francisco, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA
- Global Programs for Research and Training, Malaria Elimination Initiative Namibia, Windhoek, Namibia
| | - Patrick McCreesh
- Department of Pediatrics, University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd, TX, Dallas, USA
| | - Alysse Maglior
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd, TX, Dallas, USA
| | - Petrina Uusiku
- National Vectorborne Diseases Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Immo Kleinschmidt
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Southern Africa Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA
- Global Programs for Research and Training, Malaria Elimination Initiative Namibia, Windhoek, Namibia
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California, (UCSF), 550 16th St, San Francisco, CA, USA.
- Department of Pediatrics, University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd, TX, Dallas, USA.
- Department of Pediatrics, UCSF, San Francisco, USA.
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Kevany S. One step forward, two steps back: Tensions between malaria elimination and improved malaria surveillance in the Solomon Islands. AIMS Public Health 2020; 7:869-871. [PMID: 33294488 PMCID: PMC7719566 DOI: 10.3934/publichealth.2020067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 11/23/2020] [Indexed: 12/01/2022] Open
Abstract
The Solomon Islands experienced, between 2010, an apparent meteoric fall in the level of malaria incidence and prevalence [1]. Thanks ostensibly to the efforts of bilateral and multilateral partners and donors, annual parasite incidence (API) fell from 70 to 40 per 1,000 population. With such dramatic progress, international efforts were hailed as dramatic successes and showcased as progress towards malaria elimination and eradication, Yet, paradoxically, the true caseload of malaria in the Solomon Islands has revealed a situation that calls for more, rather than less, support.
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Affiliation(s)
- Sebastian Kevany
- University of California, 550 16th Street, San Francisco, California 94158, USA
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Wangchuk S, Gyeltshen S, Dorji K, Wangdi T, Dukpa T, Namgay R, Dorjee S, Tobgay T, Chaijaroenkul W, Na-Bangchang K. Malaria elimination in Bhutan: asymptomatic malaria cases in the Bhutanese population living in malaria-risk areas and in migrant workers from India. Rev Inst Med Trop Sao Paulo 2019; 61:e52. [PMID: 31531630 PMCID: PMC6746194 DOI: 10.1590/s1678-9946201961052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/31/2019] [Indexed: 11/28/2022] Open
Abstract
In 2018, Bhutan reported 54 cases of malaria, of which six were indigenous, 14 introduced and 34 imported. Considering the continuous reduction in the number of indigenous cases, Bhutan plans to eliminate malaria by 2025 under the Bhutan Malaria Elimination Strategy. The study was conducted to assess the presence of asymptomatic plasmodial infection in both, Bhutanese population living in malaria-risk areas and in migrant workers to guide the elimination strategies. A cross-sectional study was conducted from April to May 2016 in 750 Bhutanese people and 473 migrant workers. Plasmodium falciparum and Plasmodium vivax infections were investigated by using a rapid diagnostic test (RDT) and the polymerase chain reaction (PCR). Prevalence of asymptomatic plasmodial infection based on PCR was 0.27% (95% CI: 0.05–1.07%) among Bhutanese people with a mean age of 43 years old. The proportions of males and females were 45% and 55%, respectively. Among migrant workers, the prevalence of asymptomatic plasmodial infection was 0.42% (95% CI: 0.07–1.69%) with a mean age of 30 years old. The majority of migrant workers were from the neighboring Indian State of West Bengal (57.51%), followed by Assam (12.26%). RDT in both study groups did not detect any plasmodial infection. The presence of a low prevalence of asymptomatic plasmodial infection indicates that the current elimination strategies and interventions are effective.
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Affiliation(s)
- Sonam Wangchuk
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Sonam Gyeltshen
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Kunzang Dorji
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Tenzin Wangdi
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Tobgyel Dukpa
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Rinzin Namgay
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Sithar Dorjee
- Bhutan Agriculture and Food Regulatory Authority, Thimphu, Bhutan.,Khesar Gyalpo University of Medical Science, Thimphu, Bhutan
| | - Tashi Tobgay
- Khesar Gyalpo University of Medical Science, Thimphu, Bhutan
| | - Wanna Chaijaroenkul
- Thammasat University, Cholangiocarcinoma, Chulabhorn International College of Medicine, Center of Excellence in Pharmacology and Molecular Biology of Malaria, Pathumthani, Thailand
| | - Kesara Na-Bangchang
- Thammasat University, Cholangiocarcinoma, Chulabhorn International College of Medicine, Center of Excellence in Pharmacology and Molecular Biology of Malaria, Pathumthani, Thailand
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Quah YW, Waltmann A, Karl S, White MT, Vahi V, Darcy A, Pitakaka F, Whittaker M, Tisch DJ, Barry A, Barnadas C, Kazura J, Mueller I. Molecular epidemiology of residual Plasmodium vivax transmission in a paediatric cohort in Solomon Islands. Malar J 2019; 18:106. [PMID: 30922304 PMCID: PMC6437916 DOI: 10.1186/s12936-019-2727-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 03/14/2019] [Indexed: 01/03/2023] Open
Abstract
Background Following the scale-up of intervention efforts, malaria burden has decreased dramatically in Solomon Islands (SI). Submicroscopic and asymptomatic Plasmodium vivax infections are now the major challenge for malaria elimination in this country. Since children have higher risk of contracting malaria, this study investigated the dynamics of Plasmodium spp. infections among children including the associated risk factors of residual P. vivax burden. Methods An observational cohort study was conducted among 860 children aged 0.5–12 years in Ngella (Central Islands Province, SI). Children were monitored by active and passive surveillances for Plasmodium spp. infections and illness. Parasites were detected by quantitative real-time PCR (qPCR) and genotyped. Comprehensive statistical analyses of P. vivax infection prevalence, molecular force of blood stage infection (molFOB) and infection density were conducted. Results Plasmodium vivax infections were common (overall prevalence: 11.9%), whereas Plasmodium falciparum infections were rare (0.3%) but persistent. Although children acquire an average of 1.1 genetically distinct P. vivax blood-stage infections per year, there was significant geographic heterogeneity in the risks of P. vivax infections across Ngella (prevalence: 1.2–47.4%, p < 0.01; molFOB: 0.05–4.6/year, p < 0.01). Malaria incidence was low (IR: 0.05 episodes/year-at-risk). Age and measures of high exposure were the key risk factors for P. vivax infections and disease. Malaria incidence and infection density decreased with age, indicating significant acquisition of immunity. G6PD deficient children (10.8%) that did not receive primaquine treatment had a significantly higher prevalence (aOR: 1.77, p = 0.01) and increased risk of acquiring new bloodstage infections (molFOB aIRR: 1.51, p = 0.03), underscoring the importance of anti-relapse treatment. Conclusion Residual malaria transmission in Ngella exhibits strong heterogeneity and is characterized by a high proportion of submicroscopic and asymptomatic P. vivax infections, alongside sporadic P. falciparum infections. Implementing an appropriate primaquine treatment policy to prevent P. vivax relapses and specific targeting of control interventions to high risk areas will be required to accelerate ongoing control and elimination activities. Electronic supplementary material The online version of this article (10.1186/s12936-019-2727-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi Wan Quah
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andreea Waltmann
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Stephan Karl
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Ventis Vahi
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Andrew Darcy
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Freda Pitakaka
- National Health Training & Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Maxine Whittaker
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | | | - Alyssa Barry
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Celine Barnadas
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - James Kazura
- Case Western Reserve University, Cleveland, OH, USA
| | - Ivo Mueller
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. .,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia. .,Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.
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Howes RE, Battle KE, Mendis KN, Smith DL, Cibulskis RE, Baird JK, Hay SI. Global Epidemiology of Plasmodium vivax. Am J Trop Med Hyg 2016; 95:15-34. [PMID: 27402513 PMCID: PMC5198891 DOI: 10.4269/ajtmh.16-0141] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/19/2016] [Indexed: 01/09/2023] Open
Abstract
Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded.
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Affiliation(s)
- Rosalind E. Howes
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Katherine E. Battle
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kamini N. Mendis
- Global Malaria Program, World Health Organization, Geneva, Switzerland
| | - David L. Smith
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - J. Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon I. Hay
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
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Larocca A, Moro Visconti R, Marconi M. Malaria diagnosis and mapping with m-Health and geographic information systems (GIS): evidence from Uganda. Malar J 2016; 15:520. [PMID: 27776516 PMCID: PMC5075756 DOI: 10.1186/s12936-016-1546-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 10/05/2016] [Indexed: 11/17/2022] Open
Abstract
Background Rural populations experience several barriers to accessing clinical facilities for malaria diagnosis. Increasing penetration of ICT and mobile-phones and subsequent m-Health applications can contribute overcoming such obstacles. Methods GIS is used to evaluate the feasibility of m-Health technologies as part of anti-malaria strategies. This study investigates where in Uganda: (1) malaria affects the largest number of people; (2) the application of m-Health protocol based on the mobile network has the highest potential impact. Results About 75% of the population affected by Plasmodium falciparum malaria have scarce access to healthcare facilities. The introduction of m-Health technologies should be based on the 2G protocol, as 3G mobile network coverage is still limited. The western border and the central-Southeast are the regions where m-Health could reach the largest percentage of the remote population. Six districts (Arua, Apac, Lira, Kamuli, Iganga, and Mubende) could have the largest benefit because they account for about 28% of the remote population affected by falciparum malaria with access to the 2G mobile network. Conclusions The application of m-Health technologies could improve access to medical services for distant populations. Affordable remote malaria diagnosis could help to decongest health facilities, reducing costs and contagion. The combination of m-Health and GIS could provide real-time and geo-localized data transmission, improving anti-malarial strategies in Uganda. Scalability to other countries and diseases looks promising.
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Affiliation(s)
| | | | - Michele Marconi
- Research and Consulting GIS, Natural Resources Management, Marine Ecology, Disaster Risk Reduction, Hue, Vietnam
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West N, Gyeltshen S, Dukpa S, Khoshnood K, Tashi S, Durante A, Parikh S. An Evaluation of the National Malaria Surveillance System of Bhutan, 2006-2012 as It Approaches the Goal of Malaria Elimination. Front Public Health 2016; 4:167. [PMID: 27595095 PMCID: PMC4990597 DOI: 10.3389/fpubh.2016.00167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/29/2016] [Indexed: 01/26/2023] Open
Abstract
INTRODUCTION Bhutan is progressing toward malaria elimination. The purpose of this evaluation was to assess the ability of the surveillance system from 2006 to 2012 to meet the objectives of the Bhutan Vector-borne Disease Control Program (VDCP) and to highlight priorities requiring attention as the nation transitions to elimination. METHODS The evaluation was conducted using the Center for Disease Control guidelines for evaluating public health surveillance systems. Data sources included a search of publically available literature, VDCP program data, and interviews with malaria surveillance personnel. Blood slide quality assurance and control through formal assessment of slide preparation and measures of between-reader correlation were performed. RESULTS Total malaria cases declined from 2006 to 2012. The average slide positivity rate decreased from 3.4% in 2006 to 0.2% in 2012. The proportion of non-residents in all cases increased to its highest value of 22.6% in 2012, and significant clustering in the border regions of India was noted, with Sarpang accounting for more cases than any other district from 2009 onward. Case detection was almost exclusively passive, but flexibility and sensitivity was demonstrated by the later addition of active case detection and specification of imported and locally acquired cases. Spatial data were limited to the village level, not allowing identification of transmission hotspots. For blood smears, statistical measures of between-reader agreement and predictive value were not computed. Blood smear quality was suboptimal by at least one criterion in over half of evaluated smears. Timeliness in reporting of cases was on a weekly to monthly basis, and did not meet the WHO goal of immediate notification. CONCLUSION As of 2012, the national malaria surveillance system demonstrated flexibility, representativeness, simplicity, and stability. The full potential for data analysis was not yet realized. Attaining the goal of malaria elimination will require system function enhancement through increased and more accurate case detection and rapid investigation, improved health worker training and accountability, focally targeted response measures, and, in particular, the challenge of finding re-introductions of infections from India. Many such measure have been undertaken or planned as part of the next phase of the Bhutan's National Strategic Plan.
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Affiliation(s)
- Nicole West
- Yale School of Public Health and Medicine , New Haven, CT , USA
| | - Sonam Gyeltshen
- Vector-Borne Disease Control Programme, Department of Public Health, Ministry of Health , Gelephu , Bhutan
| | - Singye Dukpa
- Vector-Borne Disease Control Programme, Department of Public Health, Ministry of Health , Gelephu , Bhutan
| | - Kaveh Khoshnood
- Yale School of Public Health and Medicine , New Haven, CT , USA
| | - Sonam Tashi
- Vector-Borne Disease Control Programme, Department of Public Health, Ministry of Health , Gelephu , Bhutan
| | - Amanda Durante
- City of New Haven Department of Health , New Haven, CT , USA
| | - Sunil Parikh
- Yale School of Public Health and Medicine , New Haven, CT , USA
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11
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Canavati SE, Lawford HLS, Fatunmbi BS, Lek D, Top-Samphor N, Leang R, Dondorp AM, Huy R, Kazadi WM. Establishing research priorities for malaria elimination in the context of the emergency response to artemisinin resistance framework-the Cambodian approach. Malar J 2016; 15:120. [PMID: 26916933 PMCID: PMC4766599 DOI: 10.1186/s12936-016-1117-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 01/22/2016] [Indexed: 11/10/2022] Open
Abstract
Background Countries of the greater Mekong subregion have made a transition from malaria control to an aim for falciparum and vivax malaria elimination. The elimination of falciparum malaria will have to be achieved against a background of increasing artemisinin and multi-drug resistance. This ambitious goal requires an operational research (OR) agenda that addresses the dynamic challenges encountered on the path to elimination, which will need to be flexible and developed in close relation with the cambodian national programme for parasitology, entomology and malaria control (CNM). In Cambodia, a number of meetings with stakeholders were convened by the CNM and emergency response to artemisinin resistance (ERAR) hub, producing an initial list of priority OR topics. The process and outcome of these meetings are described, which could serve as a template for other countries in the region. Methods A landscaping exercise was conducted to gather all past, on-going and planned malaria focussed OR activities conducted by the cambodian research consortium in Cambodia and categorized according to research theme. The six themes included (1) malaria epidemiology, surveillance and response, (2) malaria case management, (3) malaria vector control, (4) malaria behavioural issues, (5) malaria clinical studies, and (6) other vector-borne diseases (dengue, neglected tropical diseases, soil-transmitted helminths). The different themes were discussed in small focus groups, which made an initial prioritization list which was then presented to a plenary group for further discussion. This produced a list of research questions ranked according to priority. Results OR priorities produced by the thematic groups were discussed in the plenary meeting and given a priority score by group voting. A list of 17 OR questions were developed, finalized and listed, which included questions on surveillance, active case detection and treatment efficacy. Conclusion This paper describes ERAR’s work on supporting Cambodia’s transition to malaria elimination by identifying national operational research priorities. ERAR has initiated and currently plays a critical role in the development of country specific research agendas for malaria elimination. The first example of this has been the described exercise in Cambodia, which could serve a template for setting OR priorities in the wider region.
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Affiliation(s)
- Sara E Canavati
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, Thailand.
| | - Harriet L S Lawford
- The National Center for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia.
| | - Bayo S Fatunmbi
- Emergency Response to Artemisinin Resistance, WHO Representative Office in Cambodia, Penh Phnom Penh, Cambodia.
| | - Dysoley Lek
- The National Center for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia.
| | - Narann Top-Samphor
- Emergency Response to Artemisinin Resistance, WHO Representative Office in Cambodia, Penh Phnom Penh, Cambodia.
| | - Rithea Leang
- The National Center for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia.
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Rekol Huy
- The National Center for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia.
| | - Walter M Kazadi
- Emergency Response to Artemisinin Resistance, WHO Representative Office in Cambodia, Penh Phnom Penh, Cambodia.
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Shafique M, Edwards HM, De Beyl CZ, Thavrin BK, Min M, Roca-Feltrer A. Positive deviance as a novel tool in malaria control and elimination: methodology, qualitative assessment and future potential. Malar J 2016; 15:91. [PMID: 26879638 PMCID: PMC4754848 DOI: 10.1186/s12936-016-1129-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Positive deviance (PD) is an asset-based, community-driven approach to behaviour change that has successfully been applied to address many health and social problems. It is yet to have been assessed for malaria control but may represent a promising tool for malaria elimination given its suitability in targeting small and remote population groups, apparent sustainability and ability to instil a high amount of community mobilisation. Here, the PD methodology as applied to malaria is explained, with focus upon and qualitative assessment of a proof of concept study in Cambodia. METHODS Three villages in Battambang, northwestern Cambodia were selected for the intervention, with an estimated population of 5036 including both residents and migrant workers. In August 2010, field teams conducted a 1 week PD process to sensitise and mobilise the community, establish normative behaviours in relation to malaria control and prevention, identify positive deviant behaviours from within the community, and identify PD volunteers. Until March 2011, PD volunteers were supported by field teams via monthly meetings to conduct activities in their respective communities to increase practice of PD behaviours. In February 2012, 1 year following the end of external support, evaluative interviews were conducted with community members to qualitatively assess community acceptance and interpretation of the PD intervention, perceived behaviour changes, and perceived positive outcomes. RESULTS Qualitative data from focus group discussions and in-depth interviews showed that the PD approach was well-accepted into the communities and created a strong sense of community empowerment. Positive behaviour change was linked to the PD intervention, including greater usage of nets by forest goers, and use of public health facilities for malaria diagnosis and treatment. One year following the end of external assistance, PD volunteers were still conducting activities in their respective communities. CONCLUSIONS PD offers a promising tool in malaria control and elimination settings. Work is ongoing to quantitatively measure impact of PD on behaviours and malaria transmission and once gathered, national malaria control programmes should be encouraged to look at including PD as part of their national strategies. Feasibility of scale-up, cost-effectiveness, and applicability to other settings and diseases is also currently being explored.
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Affiliation(s)
- Muhammad Shafique
- Malaria Consortium Asia, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavidhi Road, Bangkok, 10400, Thailand.
| | - Hannah M Edwards
- Malaria Consortium Asia, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavidhi Road, Bangkok, 10400, Thailand.
| | | | - Bou Kheng Thavrin
- Cambodia's National Centre for Parasitology, Entomology and Malaria Control (CNM), Phnom Penh, Cambodia.
| | - Myo Min
- Myanmar Medical Association (MMA), No.249, Theinbyu Road, Mingalar Taung Nyunt Tsp, Yangon, Myanmar.
| | - Arantxa Roca-Feltrer
- Malaria Consortium Asia, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavidhi Road, Bangkok, 10400, Thailand.
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Tadesse FG, Pett H, Baidjoe A, Lanke K, Grignard L, Sutherland C, Hall T, Drakeley C, Bousema T, Mamo H. Submicroscopic carriage of Plasmodium falciparum and Plasmodium vivax in a low endemic area in Ethiopia where no parasitaemia was detected by microscopy or rapid diagnostic test. Malar J 2015; 14:303. [PMID: 26242243 PMCID: PMC4524028 DOI: 10.1186/s12936-015-0821-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/23/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Motivated by the success in malaria control that was documented over the last decade Ethiopia is aiming at malaria elimination by 2020 in selected districts. It is currently unknown if asymptomatic, submicroscopic malaria parasite carriage may form a hurdle to achieve elimination. The elimination effort may further be complicated by possible glucose-6 phosphate dehydrogenase (G6PD) deficiency which would hinder the use of 8-aminoquinolines in the elimination efforts. METHOD In February 2014 a community-based cross-sectional survey was conducted in Malo, southwest Ethiopia. Finger-prick blood samples (n = 555) were tested for presence of Plasmodium falciparum and Plasmodium vivax with microscopy, rapid diagnostic test (RDT), and nested polymerase chain reaction (nPCR). Multiplicity of P. falciparum infections was determined based on genotyping the polymorphic merozoite surface protein-2 (MSP-2) gene. Individuals were also genotyped for mutations in the gene that produces G6PD. RESULTS All study participants were malaria infection negative by microscopy and RDT. Nested PCR revealed P. falciparum mono-infection in 5.2% (29/555), P. vivax mono-infection in 4.3% (24/555) and mixed infection in 0.2% (1/555) of individuals. All parasitemic individuals were afebrile (axillary temperature <37.5°C). None of the study participants carried mutations for the G6PD African A-(202GA) and Mediterranean (563CT) variants. All infections, except one, were single-clone infection by MSP-2 genotyping. CONCLUSION The detection of a substantial number of subpatent malaria infections in an apparently asymptomatic population without evidence for malaria transmission by conventional diagnostics raises questions about the path to malaria elimination. It is currently unknown how important these infections are for sustaining malaria transmission in the study sites. The absence of G6PD deficiency indicates that 8-aminoquinolines may be safely deployed to accelerate elimination initiatives.
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Affiliation(s)
- Fitsum G Tadesse
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, 6525GA, Nijmegen, The Netherlands.
- Medical Biotechnology Unit, Institute of Biotechnology, Addis Ababa University, POBox 1176, Addis Ababa, Ethiopia.
| | - Helmi Pett
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, 6525GA, Nijmegen, The Netherlands.
| | - Amrish Baidjoe
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, 6525GA, Nijmegen, The Netherlands.
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, 6525GA, Nijmegen, The Netherlands.
| | - Lynn Grignard
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Colin Sutherland
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Tom Hall
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Chris Drakeley
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, 6525GA, Nijmegen, The Netherlands.
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Hassen Mamo
- Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Addis Ababa University, POBox 1176, Addis Ababa, Ethiopia.
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Watanabe N, Kaneko A, Yamar S, Taleo G, Tanihata T, Lum JK, Larson PS, Shearer NBC. A prescription for sustaining community engagement in malaria elimination on Aneityum Island, Vanuatu: an application of Health Empowerment Theory. Malar J 2015; 14:291. [PMID: 26228787 PMCID: PMC4521369 DOI: 10.1186/s12936-015-0779-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 06/28/2015] [Indexed: 11/16/2022] Open
Abstract
Background Community engagement has contributed to disease control and elimination in many countries. Community engagement in malaria elimination (ME) on Aneityum Island has been sustained since its introduction in the early 1990s. Capacity developed within this population has led to a health empowered community response. Health Empowerment Theory (HET) can account for the innovative community actions and capacity development efforts taken to realize and sustain meaningful changes in well-being. This study used the HET framework to investigate participant perceptions of ME efforts on the island focusing on two HET elements, personal and social-contextual resources. The purpose of this study was to explore the role of empowerment as a critical element of community engagement. Methods Six focus group discussions, ten key informant interviews and 17 in-depth interviews were conducted in July 2012 on Aneityum. Both deductive and inductive approaches to qualitative content analysis were used to identify themes, which were condensed, coded and classified based on the HET elements above. Results Awareness and use of personal and social-contextual resources played an important role in ME efforts. Most participants shared their knowledge to prevent malaria reintroduction. Many participants reported their skills needed for behavioral maintenance, problem-solving or leadership. Participants who perceived a threat took preventive actions even in the dry season. Community leaders focused on second generation capacity development. A local health coalition provided ME services. Members of networks were sources of information and assistance. Face-to-face was the preferred method of communication. Barriers to engagement (e.g., financial difficulties, health literacy issues and underdeveloped infrastructure) were minimized through active collaboration and mutual assistance. Conclusions In the community engagement continuum, health empowerment develops incrementally overtime as people gain their knowledge and skills, form coalitions and develop collaborative networks (social capital) to make decisions and take action for change. Community engagement, which facilitates local personal and social-contextual resource development, has potential for ME and multilevel empowerment through community-based capacity development processes. These self-empowered communities have written and will continue to write a ‘prescription’ for sustaining high levels of engagement. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0779-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Noriko Watanabe
- Department of Parasitology, Osaka City University Graduate School of Medicine, Osaka, Japan.
| | - Akira Kaneko
- Department of Parasitology, Osaka City University Graduate School of Medicine, Osaka, Japan. .,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Sam Yamar
- Ministry of Health, Port Vila, Vanuatu.
| | | | - Takeo Tanihata
- Department of Infectious Disease Control, Healthcare Centre of Kobe, Kobe, Japan.
| | - J Koji Lum
- Department of Anthropology and Biological Sciences, Binghamton University, Binghamton, NY, USA.
| | - Peter S Larson
- Nagasaki University Institute of Tropical Medicine, Nagasaki, Japan. .,University of Michigan School of Natural Resources and Environment, Ann Arbor, MI, USA.
| | - Nelma B C Shearer
- Hartford Centre of Gerontological Nursing Excellence, College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, USA.
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High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands. PLoS Negl Trop Dis 2015; 9:e0003758. [PMID: 25996619 PMCID: PMC4440702 DOI: 10.1371/journal.pntd.0003758] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/13/2015] [Indexed: 12/26/2022] Open
Abstract
Introduction Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. Methods In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). Results By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and outbreaks due to travel to nearby islands with higher malaria endemicity remains. Solomon Islands, an island nation in the Southwest Pacific that has seen dramatic reductions in malaria transmission over the past 20 years, is aiming for malaria elimination. There is an increasing recognition that a substantial reservoir of asymptomatic and often sub-microscopic Plasmodium spp. infections exists even in low transmission settings. However, the potential role for these infections in sustaining transmission and the difference in response of the two most common malaria parasites, P. vivax and P. falciparum, to intensified control remains unclear. In May-June 2012, we therefore performed a cross-sectional survey of 3501 residents of all ages of Ngella, a low transmission area in Central Islands Province, to assess the prevalence of P. vivax and P. falciparum infection, determine the proportion of sub-microscopic and afebrile infections and evaluate whether gametocytaemic, and thus potentially infectious, individuals are present. Our survey showed a marked epidemiological contrast between P. vivax and P. falciparum. Although prevalence varied significantly among different regions of Ngella, P. vivax remains firmly endemic, with high rates of sub-microscopic, afebrile and genetically diverse infections. The presence of gametocytes among both sub-microscopic and microscopy positive, asymptomatic infections indicates that these infections contribute significantly to sustaining P. vivax transmission. P. falciparum, on the other hand, appears to be more amenable to control interventions. Only five P. falciparum infected individuals were detected, and all were residents of the same village. These infections carried the same msp2 clone. This difference highlights the larger challenge of eliminating P. vivax compared to P. falciparum in areas where they are co-endemic. In particular, the challenge posed by the presence of a large reservoir of silent P. vivax infections will need to be addressed if control of this parasite is to be accelerated and elimination achieved.
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Bousema T, Okell L, Felger I, Drakeley C. Asymptomatic malaria infections: detectability, transmissibility and public health relevance. Nat Rev Microbiol 2014; 12:833-40. [PMID: 25329408 DOI: 10.1038/nrmicro3364] [Citation(s) in RCA: 442] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most Plasmodium falciparum infections that are detected in community surveys are characterized by low-density parasitaemia and the absence of clinical symptoms. Molecular diagnostics have shown that this asymptomatic parasitic reservoir is more widespread than previously thought, even in low-endemic areas. In this Opinion article, we describe the detectability of asymptomatic malaria infections and the relevance of submicroscopic infections for parasite transmission to mosquitoes and for community interventions that aim at reducing transmission. We argue that wider deployment of molecular diagnostic tools is needed to provide adequate insight into the epidemiology of malaria and infection dynamics to aid elimination efforts.
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Affiliation(s)
- Teun Bousema
- 1] London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK. [2] Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Lucy Okell
- Imperial College, London, London SW7 2AZ, UK
| | | | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Bosman P, Stassijns J, Nackers F, Canier L, Kim N, Khim S, Alipon SC, Chuor Char M, Chea N, Dysoley L, Van den Bergh R, Etienne W, De Smet M, Ménard D, Kindermans JM. Plasmodium prevalence and artemisinin-resistant falciparum malaria in Preah Vihear Province, Cambodia: a cross-sectional population-based study. Malar J 2014; 13:394. [PMID: 25288380 PMCID: PMC4200124 DOI: 10.1186/1475-2875-13-394] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/29/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intensified efforts are urgently needed to contain and eliminate artemisinin-resistant Plasmodium falciparum in the Greater Mekong subregion. Médecins Sans Frontières plans to support the Ministry of Health in eliminating P. falciparum in an area with artemisinin resistance in the north-east of Cambodia. As a first step, the prevalence of Plasmodium spp. and the presence of mutations associated with artemisinin resistance were evaluated in two districts of Preah Vihear Province. METHODS A cross-sectional population-based study using a two-stage cluster sampling was conducted in the rural districts of Chhaeb and Chey Saen, from September to October 2013. In each district, 30 clusters of 10 households were randomly selected. In total, blood samples were collected for 1,275 participants in Chhaeb and 1,224 in Chey Saen. Prevalence of Plasmodium spp. was assessed by PCR on dried blood spots. Plasmodium falciparum positive samples were screened for mutations in the K13-propeller domain gene (PF3D7_1343700). RESULT The prevalence of Plasmodium spp. was estimated at 1.49% (95% CI 0.71-3.11%) in Chhaeb and 2.61% (95% CI 1.45-4.66%) in Chey Saen. Twenty-seven samples were positive for P. falciparum, giving a prevalence of 0.16% (95% CI 0.04-0.65) in Chhaeb and 2.04% (95% CI 1.04-3.99%) in Chey Saen. Only 4.0% of the participants testing positive presented with fever or history of fever. K13-propeller domain mutant type alleles (C580Y and Y493H) were found, only in Chey Saen district, in seven out of 11 P. falciparum positive samples with enough genetic material to allow testing. CONCLUSION The overall prevalence of P. falciparum was low in both districts but parasites presenting mutations in the K13-propeller domain gene, strongly associated with artemisinin-resistance, are circulating in Chey Saen.The prevalence might be underestimated because of the absentees - mainly forest workers - and the workers of private companies who were not included in the study. These results confirm the need to urgently develop and implement targeted interventions to contain and eliminate P. falciparum malaria in this district before it spreads to other areas.
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Affiliation(s)
| | - Jorgen Stassijns
- Médecins Sans Frontières, Duprestreet 94, 1090 Brussels, Belgium.
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Oloifana-Polosovai H, Gwala J, Harrington H, Massey PD, Ribeyro E, Flores A, Speare C, McBride E, MacLaren D, Speare R. A marked decline in the incidence of malaria in a remote region of Malaita, Solomon Islands, 2008 to 2013. Western Pac Surveill Response J 2014; 5:30-9. [PMID: 25320674 PMCID: PMC4197191 DOI: 10.5365/wpsar.2014.5.3.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SETTING Atoifi Adventist Hospital (AAH), Solomon Islands, the only hospital in the East Kwaio region. OBJECTIVE To use routine surveillance data to assess the trends in malaria from 2008 to 2013. DESIGN Descriptive study of records from (1) AAH laboratory malaria records; (2) admissions to AAH for malaria; and (3) malaria treatments from outpatient records. RESULTS AAH examined 35 608 blood films and diagnosed malaria in 4443 samples comprised of 2667 Plasmodium falciparum (Pf) and 1776 Plasmodium vivax (Pv). Between 2008 and 2013 the total number of malaria cases detected annually decreased by 86.5%, Pf by 96.7% and Pv by 65.3%. The ratio of Pf to Pv reversed in 2010 from 2.06 in 2008 to 0.19 in 2013. For 2013, Pf showed a seasonal pattern with no cases diagnosed in four months. From 2008 to 2013 admissions in AAH for malaria declined by 90.8%, and malaria mortality fell from 54 per 100 000 to zero. The annual parasite index (API) for 2008 and 2013 was 195 and 24, respectively. Village API has identified a group of villages with higher malaria incidence rates. CONCLUSION The decline in malaria cases in the AAH catchment area has been spectacular, particularly for Pf. This was supported by three sources of hospital surveillance data (laboratory, admissions and treatment records). The decline was associated with the use of artemisinin-based combined therapy and improved vertical social capital between the AAH and the local communities. Calculating village-specific API has highlighted which villages need to be targeted by the AAH malaria control team.
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Affiliation(s)
| | - John Gwala
- Atoifi Adventist Hospital, Atoifi, Malaita, Solomon Islands
| | | | - Peter D Massey
- Health Protection, Hunter New England Population Health, Tamworth, Australia
| | - Elmer Ribeyro
- Atoifi Adventist Hospital, Atoifi, Malaita, Solomon Islands
| | | | | | - Edwin McBride
- College of Medicine and Dentistry, James Cook University, Cairns, Australia
| | - David MacLaren
- College of Medicine and Dentistry, James Cook University, Cairns, Australia
| | - Rick Speare
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
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Marston L, Kelly GC, Hale E, Clements ACA, Hodge A, Jimenez-Soto E. Cost analysis of the development and implementation of a spatial decision support system for malaria elimination in Solomon Islands. Malar J 2014; 13:325. [PMID: 25130064 PMCID: PMC4148529 DOI: 10.1186/1475-2875-13-325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 08/11/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The goal of malaria elimination faces numerous challenges. New tools are required to support the scale up of interventions and improve national malaria programme capacity to conduct detailed surveillance. This study investigates the cost factors influencing the development and implementation of a spatial decision support system (SDSS) for malaria elimination in the two elimination provinces of Isabel and Temotu, Solomon Islands. METHOD Financial and economic costs to develop and implement a SDSS were estimated using the Solomon Islands programme's financial records. Using an ingredients approach, verified by stakeholders and operational reports, total costs for each province were quantified. A budget impact sensitivity analysis was conducted to investigate the influence of variations in standard budgetary components on the costs and to identify potential cost savings. RESULTS A total investment of US$ 96,046 (2012 constant dollars) was required to develop and implement the SDSS in two provinces (Temotu Province US$ 49,806 and Isabel Province US$ 46,240). The single largest expense category was for computerized equipment totalling approximately US$ 30,085. Geographical reconnaissance was the most expensive phase of development and implementation, accounting for approximately 62% of total costs. Sensitivity analysis identified different cost factors between the provinces. Reduced equipment costs would deliver a budget saving of approximately 10% in Isabel Province. Combined travel costs represented the greatest influence on the total budget in the more remote Temotu Province. CONCLUSION This study provides the first cost analysis of an operational surveillance tool used specifically for malaria elimination in the South-West Pacific. It is demonstrated that the costs of such a decision support system are driven by specialized equipment and travel expenses. Such factors should be closely scrutinized in future programme budgets to ensure maximum efficiencies are gained and available resources are allocated effectively.
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Affiliation(s)
| | | | | | | | - Andrew Hodge
- The University of Queensland, School of Population Health, Public Health Building, Herston Road, Herston, Brisbane, QLD 4006, Australia.
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Tambo E, Ai L, Zhou X, Chen JH, Hu W, Bergquist R, Guo JG, Utzinger J, Tanner M, Zhou XN. Surveillance-response systems: the key to elimination of tropical diseases. Infect Dis Poverty 2014; 3:17. [PMID: 24971165 PMCID: PMC4071800 DOI: 10.1186/2049-9957-3-17] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 05/09/2014] [Indexed: 12/15/2022] Open
Abstract
Tropical diseases remain a major cause of morbidity and mortality in developing countries. Although combined health efforts brought about significant improvements over the past 20 years, communities in resource-constrained settings lack the means of strengthening their environment in directions that would provide less favourable conditions for pathogens. Still, the impact of infectious diseases is declining worldwide along with progress made regarding responses to basic health problems and improving health services delivery to the most vulnerable populations. The London Declaration on Neglected Tropical Diseases (NTDs), initiated by the World Health Organization's NTD roadmap, set out the path towards control and eventual elimination of several tropical diseases by 2020, providing an impetus for local and regional disease elimination programmes. Tropical diseases are often patchy and erratic, and there are differing priorities in resources-limited and endemic countries at various levels of their public health systems. In order to identify and prioritize strategic research on elimination of tropical diseases, the 'First Forum on Surveillance-Response System Leading to Tropical Diseases Elimination' was convened in Shanghai in June 2012. Current strategies and the NTD roadmap were reviewed, followed by discussions on how to identify and critically examine prevailing challenges and opportunities, including inter-sectoral collaboration and approaches for elimination of several infectious, tropical diseases. A priority research agenda within a 'One Health-One World' frame of global health was developed, including (i) the establishment of a platform for resource-sharing and effective surveillance-response systems for Asia Pacific and Africa with an initial focus on elimination of lymphatic filariasis, malaria and schistosomiasis; (ii) development of new strategies, tools and approaches, such as improved diagnostics and antimalarial therapies; (iii) rigorous validation of surveillance-response systems; and (iv) designing pilot studies to transfer Chinese experiences of successful surveillance-response systems to endemic countries with limited resources.
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Affiliation(s)
- Ernest Tambo
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- Biochemistry Department, Center for Sustainable Malaria Control, Faculty of Natural & Agricultural Sciences, University of Pretoria, Hatfield 0028, South Africa
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
| | - Lin Ai
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
| | - Xia Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- Sochow University, Suzhou 215123, People’s Republic of China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
| | - Wei Hu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- School of Life Science, Fudan University, Shanghai 200433, People’s Republic of China
| | | | - Jia-Gang Guo
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- Department of Control of Neglected Tropical Diseases, World Health Organization, Avenue Appia 20, CH-1211 Geneva, Switzerland
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
| | - Marcel Tanner
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, People’s Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
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Lin JT, Saunders DL, Meshnick SR. The role of submicroscopic parasitemia in malaria transmission: what is the evidence? Trends Parasitol 2014; 30:183-90. [PMID: 24642035 DOI: 10.1016/j.pt.2014.02.004] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/10/2014] [Accepted: 02/13/2014] [Indexed: 12/18/2022]
Abstract
Achieving malaria elimination requires targeting the human reservoir of infection, including those with asymptomatic infection. Smear-positive asymptomatic infections detectable by microscopy are an important reservoir because they often persist for months and harbor gametocytes, the parasite stage infectious to mosquitoes. However, many asymptomatic infections are submicroscopic and can only be detected by molecular methods. Although there is some evidence that individuals with submicroscopic malaria can infect mosquitoes, transmission is much less likely to occur at submicroscopic gametocyte levels. As malaria elimination programs pursue mass screening and treatment of asymptomatic individuals, further research should strive to define the degree to which submicroscopic malaria contributes to the infectious reservoir and, in turn, what diagnostic detection threshold is needed to effectively interrupt transmission.
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Affiliation(s)
- Jessica T Lin
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
| | - David L Saunders
- Department of Immunology and Medicine, USAMC Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
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Lindblade KA, Steinhardt L, Samuels A, Kachur SP, Slutsker L. The silent threat: asymptomatic parasitemia and malaria transmission. Expert Rev Anti Infect Ther 2014; 11:623-39. [PMID: 23750733 DOI: 10.1586/eri.13.45] [Citation(s) in RCA: 338] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Scale-up of malaria control interventions has resulted in a substantial decline in global malaria morbidity and mortality. Despite this achievement, there is evidence that current interventions alone will not lead to malaria elimination in most malaria-endemic areas and additional strategies need to be considered. Use of antimalarial drugs to target the reservoir of malaria infection is an option to reduce the transmission of malaria between humans and mosquito vectors. However, a large proportion of human malaria infections are asymptomatic, requiring treatment that is not triggered by care-seeking for clinical illness. This article reviews the evidence that asymptomatic malaria infection plays an important role in malaria transmission and that interventions to target this parasite reservoir may be needed to achieve malaria elimination in both low- and high-transmission areas.
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Affiliation(s)
- Kim A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, MS A-06, Atlanta, GA 30333, USA.
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Bosu WK. Learning lessons from operational research in infectious diseases: can the same model be used for noncommunicable diseases in developing countries? ADVANCES IN MEDICAL EDUCATION AND PRACTICE 2014; 5:469-82. [PMID: 25506254 PMCID: PMC4259801 DOI: 10.2147/amep.s47412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
About three-quarters of global deaths from noncommunicable diseases (NCDs) occur in developing countries. Nearly a third of these deaths occur before the age of 60 years. These deaths are projected to increase, fueled by such factors as urbanization, nutrition transition, lifestyle changes, and aging. Despite this burden, there is a paucity of research on NCDs, due to the higher priority given to infectious disease research. Less than 10% of research on cardiovascular diseases comes from developing countries. This paper assesses what lessons from operational research on infectious diseases could be applied to NCDs. The lessons are drawn from the priority setting for research, integration of research into programs and routine service delivery, the use of routine data, rapid-assessment survey methods, modeling, chemoprophylaxis, and the translational process of findings into policy and practice. With the lines between infectious diseases and NCDs becoming blurred, it is justifiable to integrate the programs for the two disease groups wherever possible, eg, screening for diabetes in tuberculosis. Applying these lessons will require increased political will, research capacity, ownership, use of local expertise, and research funding.
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Affiliation(s)
- William K Bosu
- Department of Epidemics and Disease Control, West African Health Organisation, Bobo-Dioulasso, Burkina Faso
- Correspondence: William K Bosu, Department of Epidemics and Disease Control, West African Health Organisation, 175 Ouzzein Coulibaly Avenue, Bobo-Dioulasso 01 BP 153, Burkina Faso, Email
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24
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Brieger WR. Investing in malaria research in challenging financial times. Int Health 2013; 5:161-2. [PMID: 24030265 DOI: 10.1093/inthealth/iht014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- William R Brieger
- Department of International Health, Johns Hopkins Bloomberg School of Public Health and Senior Malaria Specialist, Jhpiego, Baltimore, MD, USA; E-mail address:
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25
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Kelly GC, Hale E, Donald W, Batarii W, Bugoro H, Nausien J, Smale J, Palmer K, Bobogare A, Taleo G, Vallely A, Tanner M, Vestergaard LS, Clements ACA. A high-resolution geospatial surveillance-response system for malaria elimination in Solomon Islands and Vanuatu. Malar J 2013; 12:108. [PMID: 23514410 PMCID: PMC3618239 DOI: 10.1186/1475-2875-12-108] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 03/14/2013] [Indexed: 11/30/2022] Open
Abstract
Background A high-resolution surveillance-response system has been developed within a geographic information system (GIS) to support malaria elimination in the Pacific. This paper examines the application of a GIS-based spatial decision support system (SDSS) to automatically locate and map the distribution of confirmed malaria cases, rapidly classify active transmission foci, and guide targeted responses in elimination zones. Methods Customized SDSS-based surveillance-response systems were developed in the three elimination provinces of Isabel and Temotu, Solomon Islands and Tafea, Vanuatu. Confirmed malaria cases were reported to provincial malaria offices upon diagnosis and updated into the respective SDSS as part of routine operations throughout 2011. Cases were automatically mapped by household within the SDSS using existing geographical reconnaissance (GR) data. GIS queries were integrated into the SDSS-framework to automatically classify and map transmission foci based on the spatiotemporal distribution of cases, highlight current areas of interest (AOI) regions to conduct foci-specific targeted response, and extract supporting household and population data. GIS simulations were run to detect AOIs triggered throughout 2011 in each elimination province and conduct a sensitivity analysis to calculate the proportion of positive cases, households and population highlighted in AOI regions of a varying geographic radius. Results A total of 183 confirmed cases were reported and mapped using the SDSS throughout 2011 and used to describe transmission within a target population of 90,354. Automatic AOI regions were also generated within each provincial SDSS identifying geographic areas to conduct response. 82.5% of confirmed cases were automatically geo-referenced and mapped at the household level, with 100% of remaining cases geo-referenced at a village level. Data from the AOI analysis indicated different stages of progress in each province, highlighting operational implications with regards to strategies for implementing surveillance-response in consideration of the spatiotemporal nature of cases as well as logistical and financial constraints of the respective programmes. Conclusions Geospatial systems developed to guide Pacific Island malaria elimination demonstrate the application of a high resolution SDSS-based approach to support key elements of surveillance-response including understanding epidemiological variation within target areas, implementing appropriate foci-specific targeted response, and consideration of logistical constraints and costs.
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Affiliation(s)
- Gerard C Kelly
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Brisbane, Australia.
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Hoyer S, Nguon S, Kim S, Habib N, Khim N, Sum S, Christophel EM, Bjorge S, Thomson A, Kheng S, Chea N, Yok S, Top S, Ros S, Sophal U, Thompson MM, Mellor S, Ariey F, Witkowski B, Yeang C, Yeung S, Duong S, Newman RD, Menard D. Focused Screening and Treatment (FSAT): a PCR-based strategy to detect malaria parasite carriers and contain drug resistant P. falciparum, Pailin, Cambodia. PLoS One 2012; 7:e45797. [PMID: 23049687 PMCID: PMC3462177 DOI: 10.1371/journal.pone.0045797] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 08/24/2012] [Indexed: 11/19/2022] Open
Abstract
Recent studies have shown that Plasmodium falciparum malaria parasites in Pailin province, along the border between Thailand and Cambodia, have become resistant to artemisinin derivatives. To better define the epidemiology of P. falciparum populations and to assess the risk of the possible spread of these parasites outside Pailin, a new epidemiological tool named “Focused Screening and Treatment” (FSAT), based on active molecular detection of asymptomatic parasite carriers was introduced in 2010. Cross-sectional malariometric surveys using PCR were carried out in 20 out of 109 villages in Pailin province. Individuals detected as P. falciparum carriers were treated with atovaquone-proguanil combination plus a single dose of primaquine if the patient was non-G6PD deficient. Interviews were conducted to elicit history of cross-border travel that might contribute to the spread of artemisinin-resistant parasites. After directly observed treatment, patients were followed up and re-examined on day 7 and day 28. Among 6931 individuals screened, prevalence of P. falciparum carriers was less than 1%, of whom 96% were asymptomatic. Only 1.6% of the individuals had a travel history or plans to go outside Cambodia, with none of those tested being positive for P. falciparum. Retrospective analysis, using 2010 routine surveillance data, showed significant differences in the prevalence of asymptomatic carriers discovered by FSAT between villages classified as “high risk” and “low risk” based on malaria incidence data. All positive individuals treated and followed-up until day 28 were cured. No mutant-type allele related to atovaquone resistance was found. FSAT is a potentially useful tool to detect, treat and track clusters of asymptomatic carriers of P. falciparum along with providing valuable epidemiological information regarding cross-border movements of potential malaria parasite carriers and parasite gene flow.
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Affiliation(s)
- Stefan Hoyer
- World Health Organization, Global Malaria Programme, Geneva, Switzerland
- * E-mail: (SH); (DM)
| | - Sokomar Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | | | - Nimol Khim
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Sarorn Sum
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Eva-Maria Christophel
- World Health Organization, Regional Office for the Western Pacific, Manilla, Philippines
| | | | | | - Sim Kheng
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Nguon Chea
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Sovann Yok
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Samphornarann Top
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Seyha Ros
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Uth Sophal
- Malaria Consortium, Phnom Penh, Cambodia
| | | | | | - Frédéric Ariey
- Unité d'Immunologie Moléculaire des Parasites, Institut Pasteur, Paris, France
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Chhiang Yeang
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Shunmay Yeung
- Malaria Centre, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Socheat Duong
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Robert D. Newman
- World Health Organization, Global Malaria Programme, Geneva, Switzerland
| | - Didier Menard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
- * E-mail: (SH); (DM)
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Barclay VC, Smith RA, Findeis JL. Surveillance considerations for malaria elimination. Malar J 2012; 11:304. [PMID: 22938625 PMCID: PMC3480880 DOI: 10.1186/1475-2875-11-304] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 08/28/2012] [Indexed: 11/20/2022] Open
Abstract
Constant malaria monitoring and surveillance systems have been highlighted as critical for malaria elimination. The absence of robust monitoring and surveillance systems able to respond to outbreaks in a timely manner undeniably contributed to the failure of the last global attempt to eradicate malaria. Today, technological advances could allow for rapid detection of focal outbreaks and improved deployment of diagnostic and treatment supplies to areas needing support. However, optimizing diffusion activities (e.g., distributing vector controls and medicines, as well as deploying behaviour change campaigns) requires networks of diverse scholars to monitor, learn, and evaluate data and multiple organizations to coordinate their intervention activities. Surveillance systems that can gather, store and process information, from communities to national levels, in a centralized, widely accessible system will allow tailoring of surveillance and intervention efforts. Different systems and, thus reactions, will be effective in different endemic, geographical or socio-cultural contexts. Investing in carefully designed monitoring technologies, built for a multiple-acter, dynamic system, will help to improve malaria elimination efforts by improving the coordination, timing, coverage, and deployment of malaria technologies.
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Affiliation(s)
- Victoria C Barclay
- Department of Biology and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - Rachel A Smith
- Department of Communication Arts & Sciences, Human Development & Family Studies, and Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - Jill L Findeis
- Division of Applied Social Sciences (DASS), Agricultural & Applied Economics, CAFNR, University of Missouri, Columbia, MO, USA
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