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Muhamad P, Phompradit P, Chaijaroenkul W, Na-Bangchang K. Distribution patterns of molecular markers of antimalarial drug resistance in Plasmodium falciparum isolates on the Thai-Myanmar border during the periods of 1993-1998 and 2002-2008. BMC Genomics 2024; 25:269. [PMID: 38468205 DOI: 10.1186/s12864-023-09814-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 11/17/2023] [Indexed: 03/13/2024] Open
Abstract
BACKGROUND Polymorphisms of Plasmodium falciparum chloroquine resistance transporter (pfcrt), Plasmodium falciparum multi-drug resistance 1 (pfmdr1) and Plasmodium falciparum kelch 13-propeller (pfk13) genes are accepted as valid molecular markers of quinoline antimalarials and artemisinins. This study investigated the distribution patterns of these genes in P. falciparum isolates from the areas along the Thai-Myanmar border during the two different periods of antimalarial usage in Thailand. RESULTS Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were used to detect pfcrt mutations at codons 76, 220, 271, 326, 356, and 371 as well as pfmdr1 mutation at codon 86. The prevalence of pfcrt mutations was markedly high (96.4-99.7%) in samples collected during both periods. The proportions of mutant genotypes (number of mutant/total isolate) at codons 76, 220, 271, 326, 356 and 371 in the isolates collected during 1993-1998 (period 1) compared with 2002-2008 (period 2) were 97.9% (137/140) vs. 97.1% (401/413), 97.9% (140/143) vs. 98.8% (171/173), 97.2% (139/143) vs. 97.1% (333/343), 98.6% (140/142) vs. 99.7% (385/386), 96.4% (134/139) vs. 98.2% (378/385) and 97.8% (136/139) vs. 98.9% (375/379), respectively. Most isolates carried pfmdr1 wild-type at codon 86, with a significant difference in proportions genotypes (number of wild type/total sample) in samples collected during period 1 [92.9% (130/140)] compared with period 2 [96.9% (379/391)]. Investigation of pfmdr1 copy number was performed by real-time PCR. The proportions of isolates carried 1, 2, 3 and 4 or more than 4 copies of pfmdr1 (number of isolates carried correspondent copy number/total isolate) were significantly different between the two sample collecting periods (65.7% (90/137) vs. 87.8% (390/444), 18.2% (25/137) vs. 6.3%(28/444), 5.1% (7/137) vs. 1.4% (6/444) and 11.0% (15/137) vs. 4.5% (20/444), for period 1 vs. period 2, respectively). No pfk13 mutation was detected by nested PCR and nucleotide sequencing in all samples with successful analysis (n = 68). CONCLUSIONS The persistence of pfcrt mutations and pfmdr1 wild-types at codon 86, along with gene amplification in P. falciparum, contributes to the continued resistance of chloroquine and mefloquine in P. falciparum isolates in the study area. Regular surveillance of antimalarial drug resistance in P. falciparum, incorporating relevant molecular markers and treatment efficacy assessments, should be conducted.
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Affiliation(s)
- Phunuch Muhamad
- Drug Discovery and Development Center, Office of Advanced Science and Technology, Thammasat University, Pathumthani, 12120, Thailand
| | - Papichaya Phompradit
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand
| | - Wanna Chaijaroenkul
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and Cholangiocarcinoma, Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand
- Graduate Program in Bioclinical Sciences, Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand
| | - Kesara Na-Bangchang
- Drug Discovery and Development Center, Office of Advanced Science and Technology, Thammasat University, Pathumthani, 12120, Thailand.
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand.
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and Cholangiocarcinoma, Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand.
- Graduate Program in Bioclinical Sciences, Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12120, Thailand.
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2
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Mayor A, Ishengoma DS, Proctor JL, Verity R. Sampling for malaria molecular surveillance. Trends Parasitol 2023; 39:954-968. [PMID: 37730525 PMCID: PMC10580323 DOI: 10.1016/j.pt.2023.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
Strategic use of Plasmodium falciparum genetic variation has great potential to inform public health actions for malaria control and elimination. Malaria molecular surveillance (MMS) begins with a strategy to identify and collect parasite samples, guided by public-health priorities. In this review we discuss sampling design practices for MMS and point out epidemiological, biological, and statistical factors that need to be considered. We present examples for different use cases, including detecting emergence and spread of rare variants, establishing transmission sources and inferring changes in malaria transmission intensity. This review will potentially guide the collection of samples and data, serve as a starting point for further methodological innovation, and enhance utilization of MMS to support malaria elimination.
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Affiliation(s)
- Alfredo Mayor
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique; Department of Physiologic Sciences, Faculty of Medicine, Universidade Eduardo Mondlane, Maputo, Mozambique.
| | - Deus S Ishengoma
- National Institute for Medical Research (NIMR), Dar es Salaam, Tanzania; Faculty of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia; Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Joshua L Proctor
- Institute for Disease Modeling in Global Health, Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Robert Verity
- MRC Centre for Global Infectious Disease Analysis, Imperial College, London, UK
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3
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Bareng PN, Grignard L, Reyes R, Fornace K, Spencer F, Macalinao ML, Luchavez J, Espino FE, Drakeley C, Hafalla JCR. Prevalence and temporal changes of mutations linked to anti-malarial drug resistance in Plasmodium falciparum and Plasmodium vivax in Palawan, Philippines. Int J Infect Dis 2021; 116:174-181. [PMID: 34883232 PMCID: PMC8866131 DOI: 10.1016/j.ijid.2021.12.318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/24/2021] [Accepted: 12/02/2021] [Indexed: 11/30/2022] Open
Abstract
Plasmodium falciparum and Plasmodium vivax isolates from the Philippines were analysed. Varying mutations were found in markers linked to resistance to antimalarial drugs. None of the mutations were particularly of high prevalence. Clear temporal patterns in these mutations were observed within the past 15 years. Decrease in pfcrt and pfmdr mutations are in line with antimalarial policy change.
Objective This study provides 2016 data on the prevalence of key single nucleotide polymorphisms (SNPs) associated with antimalarial drug resistance in Palawan, Philippines. Findings were combined with historical data to model temporal changes in the prevalence of these SNPs in Plasmodium isolates. Methods Plasmodium isolates were genotyped using drug resistance markers pfmdr1, pfcrt, pfdhfr, pfdhps, kelch-13, pvmdr1, pvdhfr, and pvdhps. Temporal trends in the probability of mutations were estimated as a function of time using a binomial generalised linear model. Results All samples sequenced for Plasmodium falciparum chloroquine markers pfmdr1 and pfcrt had wild-type alleles. Varying mutation patterns were observed for the sulphadoxine/pyrimethamine markers pfdhps and pfdhfr; complete quintuplet mutations were not found. No SNPs were observed for the artemisinin marker kelch-13. For Plasmodium vivax, differing patterns were detected for pvmdr1, pvdhfr, and pvdhps. Conclusions The study findings suggest that the current drugs remain effective and that there is limited importation and establishment of resistant parasites in the area. Clear temporal trends were recognised, with prominent decreases in the proportions of pfcrt and pfmdr mutations detected within the past 15 years, consistent with a change in antimalarial drug policy. Continuous surveillance of antimalarial drug resistance is important to support malaria elimination efforts.
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Affiliation(s)
- Paolo N Bareng
- Department of Parasitology and National Reference Centre for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines.
| | - Lynn Grignard
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ralph Reyes
- Department of Parasitology and National Reference Centre for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Kim Fornace
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Freya Spencer
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ma Lourdes Macalinao
- Department of Parasitology and National Reference Centre for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Jennifer Luchavez
- Department of Parasitology and National Reference Centre for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Fe Esperanza Espino
- Department of Parasitology and National Reference Centre for Malaria and Other Parasites, Research Institute for Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Chris Drakeley
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Julius Clemence R Hafalla
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
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4
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Zhao Y, Wang L, Soe MT, Aung PL, Wei H, Liu Z, Ma T, Huang Y, Menezes LJ, Wang Q, Kyaw MP, Nyunt MH, Cui L, Cao Y. Molecular surveillance for drug resistance markers in Plasmodium vivax isolates from symptomatic and asymptomatic infections at the China-Myanmar border. Malar J 2020; 19:281. [PMID: 32758218 PMCID: PMC7409419 DOI: 10.1186/s12936-020-03354-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/28/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In the Greater Mekong sub-region, Plasmodium vivax has become the predominant species and imposes a major challenge for regional malaria elimination. This study aimed to investigate the variations in genes potentially related to drug resistance in P. vivax populations from the China-Myanmar border area. In addition, this study also wanted to determine whether divergence existed between parasite populations associated with asymptomatic and acute infections. METHODS A total of 66 P. vivax isolates were obtained from patients with acute malaria who attended clinics at the Laiza area, Kachin State, Myanmar in 2015. In addition, 102 P. vivax isolates associated with asymptomatic infections were identified by screening of volunteers without signs or symptoms from surrounding villages. Slide-positive samples were verified with nested PCR detecting the 18S rRNA gene. Multiclonal infections were further excluded by genotyping at msp-3α and msp-3β genes. Parasite DNA from 60 symptomatic cases and 81 asymptomatic infections was used to amplify and sequence genes potentially associated with drug resistance, including pvmdr1, pvcrt-o, pvdhfr, pvdhps, and pvk12. RESULTS The pvmdr1 Y976F and F1076L mutations were present in 3/113 (2.7%) and 97/113 (85.5%) P. vivax isolates, respectively. The K10 insertion in pvcrt-o gene was found in 28.2% of the parasites. Four mutations in the two antifolate resistance genes reached relatively high levels of prevalence: pvdhfr S58R (53.4%), S117N/T (50.8%), pvdhps A383G (75.0%), and A553G (36.3%). Haplotypes with wild-type pvmdr1 (976Y/997K/1076F) and quadruple mutations in pvdhfr (13I/57L/58R/61M/99H/117T/173I) were significantly more prevalent in symptomatic than asymptomatic infections, whereas the pvmdr1 mutant haplotype 976Y/997K/1076L was significantly more prevalent in asymptomatic than symptomatic infections. In addition, quadruple mutations at codons 57, 58, 61 and 117 of pvdhfr and double mutations at codons 383 and 553 of pvdhps were found both in asymptomatic and symptomatic infections with similar frequencies. No mutations were found in the pvk12 gene. CONCLUSIONS Mutations in pvdhfr and pvdhps were prevalent in both symptomatic and asymptomatic P. vivax infections, suggestive of resistance to antifolate drugs. Asymptomatic carriers may act as a silent reservoir sustaining drug-resistant parasite transmission necessitating a rational strategy for malaria elimination in this region.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Lin Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | | | - Haichao Wei
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Ziling Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Tongyu Ma
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yuanyuan Huang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Lynette J Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | | | | | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
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5
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Zhao Y, Liu Z, Soe MT, Wang L, Soe TN, Wei H, Than A, Aung PL, Li Y, Zhang X, Hu Y, Wei H, Zhang Y, Burgess J, Siddiqui FA, Menezes L, Wang Q, Kyaw MP, Cao Y, Cui L. Genetic Variations Associated with Drug Resistance Markers in Asymptomatic Plasmodium falciparum Infections in Myanmar. Genes (Basel) 2019; 10:genes10090692. [PMID: 31505774 PMCID: PMC6770986 DOI: 10.3390/genes10090692] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/31/2019] [Accepted: 09/04/2019] [Indexed: 12/30/2022] Open
Abstract
The emergence and spread of drug resistance is a problem hindering malaria elimination in Southeast Asia. In this study, genetic variations in drug resistance markers of Plasmodium falciparum were determined in parasites from asymptomatic populations located in three geographically dispersed townships of Myanmar by PCR and sequencing. Mutations in dihydrofolate reductase (pfdhfr), dihydropteroate synthase (pfdhps), chloroquine resistance transporter (pfcrt), multidrug resistance protein 1 (pfmdr1), multidrug resistance-associated protein 1 (pfmrp1), and Kelch protein 13 (k13) were present in 92.3%, 97.6%, 84.0%, 98.8%, and 68.3% of the parasites, respectively. The pfcrt K76T, pfmdr1 N86Y, pfmdr1 I185K, and pfmrp1 I876V mutations were present in 82.7%, 2.5%, 87.5%, and 59.8% isolates, respectively. The most prevalent haplotypes for pfdhfr, pfdhps, pfcrt and pfmdr1 were 51I/59R/108N/164L, 436A/437G/540E/581A, 74I/75E/76T/220S/271E/326N/356T/371I, and 86N/130E/184Y/185K/1225V, respectively. In addition, 57 isolates had three different point mutations (K191T, F446I, and P574L) and three types of N-terminal insertions (N, NN, NNN) in the k13 gene. In total, 43 distinct haplotypes potentially associated with multidrug resistance were identified. These findings demonstrate a high prevalence of multidrug-resistant P. falciparum in asymptomatic infections from diverse townships in Myanmar, emphasizing the importance of targeting asymptomatic infections to prevent the spread of drug-resistant P.falciparum.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Ziling Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Lin Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Than Naing Soe
- Department of Public Health, Ministry of Health and Sports, Nay Pyi Taw 15011, Myanmar.
| | - Huanping Wei
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Aye Than
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Pyae Linn Aung
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Yuling Li
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Xuexing Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Yubing Hu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Haichao Wei
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Yangminghui Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Jessica Burgess
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Faiza A Siddiqui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Lynette Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | | | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
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6
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Huckaby AC, Granum CS, Carey MA, Szlachta K, Al-Barghouthi B, Wang YH, Guler JL. Complex DNA structures trigger copy number variation across the Plasmodium falciparum genome. Nucleic Acids Res 2019; 47:1615-1627. [PMID: 30576466 PMCID: PMC6393310 DOI: 10.1093/nar/gky1268] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 12/04/2018] [Accepted: 12/07/2018] [Indexed: 02/06/2023] Open
Abstract
Antimalarial resistance is a major obstacle in the eradication of the human malaria parasite, Plasmodium falciparum. Genome amplifications, a type of DNA copy number variation (CNV), facilitate overexpression of drug targets and contribute to parasite survival. Long monomeric A/T tracks are found at the breakpoints of many Plasmodium resistance-conferring CNVs. We hypothesize that other proximal sequence features, such as DNA hairpins, act with A/T tracks to trigger CNV formation. By adapting a sequence analysis pipeline to investigate previously reported CNVs, we identified breakpoints in 35 parasite clones with near single base-pair resolution. Using parental genome sequence, we predicted the formation of stable hairpins within close proximity to all future breakpoint locations. Especially stable hairpins were predicted to form near five shared breakpoints, establishing that the initiating event could have occurred at these sites. Further in-depth analyses defined characteristics of these 'trigger sites' across the genome and detected signatures of error-prone repair pathways at the breakpoints. We propose that these two genomic signals form the initial lesion (hairpins) and facilitate microhomology-mediated repair (A/T tracks) that lead to CNV formation across this highly repetitive genome. Targeting these repair pathways in P. falciparum may be used to block adaptation to antimalarial drugs.
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Affiliation(s)
- Adam C Huckaby
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Claire S Granum
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Maureen A Carey
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908, USA.,Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Basel Al-Barghouthi
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA.,Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Jennifer L Guler
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA.,Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA 22908, USA
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Blanton RE. Population Genetics and Molecular Epidemiology of Eukaryotes. Microbiol Spectr 2018; 6:10.1128/microbiolspec.AME-0002-2018. [PMID: 30387414 PMCID: PMC6217834 DOI: 10.1128/microbiolspec.ame-0002-2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Indexed: 01/16/2023] Open
Abstract
Molecular epidemiology uses the distribution and organization of a pathogen's DNA to understand the distribution and determinants of disease. Since the biology of DNA for eukaryotic pathogens differs substantially from that of bacteria, the analytic approach to their molecular epidemiology can also differ. While many of the genotyping techniques presented earlier in this series, "Advances in Molecular Epidemiology of Infectious Diseases," can be applied to eukaryotes, the output must be interpreted in the light of how DNA is distributed from one generation to the next. In some cases, parasite populations can be evaluated in ways reminiscent of bacteria. They differ, however, when analyzed as sexually reproducing organisms, where all individuals are unique but the genetic composition of the population does not change unless a limited set of events occurs. It is these events (migration, mutation, nonrandom mating, selection, and genetic drift) that are of interest. At a given time, not all of them are likely to be equally important, so the list can easily be narrowed down to understand the driving forces behind the population as it is now and even what it will look like in the future. The main population characteristics measured to assess these events are differentiation and diversity, interpreted in the light of what is known about the population from observation. The population genetics of eukaryotes is important for planning and evaluation of control measures, surveillance, outbreak investigation, and monitoring of the development and spread of drug resistance. *This article is part of a curated collection.
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Affiliation(s)
- Ronald E Blanton
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH 44106
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8
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Khan MS, Schwanke-Khilji S, Yoong J, Tun ZM, Watson S, Coker RJ. Large funding inflows, limited local capacity and emerging disease control priorities: a situational assessment of tuberculosis control in Myanmar. Health Policy Plan 2018; 32:i22-i31. [PMID: 29028226 DOI: 10.1093/heapol/czx062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2017] [Indexed: 11/13/2022] Open
Abstract
There are numerous challenges in planning and implementing effective disease control programmes in Myanmar, which is undergoing internal political and economic transformations whilst experiencing massive inflows of external funding. The objective of our study-involving key informant discussions, participant observations and linked literature reviews-was to analyse how tuberculosis (TB) control strategies in Myanmar are influenced by the broader political, economic, epidemiological and health systems context using the Systemic Rapid Assessment conceptual and analytical framework. Our findings indicate that the substantial influx of donor funding, in the order of one billion dollars over a 5-year period, may be too rapid for the country's infrastructure to effectively utilize. TB control strategies thus far have tended to favour medical or technological approaches rather than infrastructure development, and appear to be driven more by perceived urgency to 'do something' rather informed by evidence of cost-effectiveness and sustainable long-term impact. Progress has been made towards ambitious targets for scaling up treatment of drug-resistant TB, although there are concerns about ensuring quality of care. We also find substantial disparities in health and funding allocation between regions and ethnic groups, which are related to the political context and health system infrastructure. Our situational assessment of emerging TB control strategies in this transitioning health system indicates that large investments by international donors may be pushing Myanmar to scale up TB and drug-resistant TB services too quickly, without due consideration given to the health system (service delivery infrastructure, human resource capacity, quality of care, equity) and epidemiological (evidence of effectiveness of interventions, prevention of new cases) context.
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Affiliation(s)
- Mishal S Khan
- Saw Swee Hock School of Public Health, National University of Singapore, Tahir Foundation Building, 12 Science Drive 2, #10-01, Singapore 117549, Singapore.,Communicable Diseases Policy Research Group, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Sara Schwanke-Khilji
- Division of Hospital Medicine, Oregon Health and Science University, Oregon, USA
| | - Joanne Yoong
- Saw Swee Hock School of Public Health, National University of Singapore, Tahir Foundation Building, 12 Science Drive 2, #10-01, Singapore 117549, Singapore.,Center for Economic and Social Research, University of Southern California, Los Angeles, CA, USA
| | - Zaw Myo Tun
- Saw Swee Hock School of Public Health, National University of Singapore, Tahir Foundation Building, 12 Science Drive 2, #10-01, Singapore 117549, Singapore
| | | | - Richard James Coker
- Communicable Diseases Policy Research Group, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,Faculty of Public Health, Mahidol University, Bangkok, Thailand
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9
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Srimuang K, Miotto O, Lim P, Fairhurst RM, Kwiatkowski DP, Woodrow CJ, Imwong M. Analysis of anti-malarial resistance markers in pfmdr1 and pfcrt across Southeast Asia in the Tracking Resistance to Artemisinin Collaboration. Malar J 2016; 15:541. [PMID: 27825353 PMCID: PMC5101715 DOI: 10.1186/s12936-016-1598-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 10/31/2016] [Indexed: 01/07/2023] Open
Abstract
Background Declining anti-malarial efficacy of artemisinin-based combination therapy, and reduced Plasmodium falciparum susceptibility to individual anti-malarials are being documented across an expanding area of Southeast Asia (SEA). Genotypic markers complement phenotypic studies in assessing the efficacy of individual anti-malarials. Methods The markers pfmdr1 and pfcrt were genotyped in parasite samples obtained in 2011–2014 at 14 TRAC (Tracking Resistance to Artemisinin Collaboration) sites in mainland Southeast Asia using a combination of PCR and next-generation sequencing methods. Results Pfmdr1 amplification, a marker of mefloquine and lumefantrine resistance, was highly prevalent at Mae Sot on the Thailand–Myanmar border (59.8% of isolates) and common (more than 10%) at sites in central Myanmar, eastern Thailand and western Cambodia; however, its prevalence was lower than previously documented in Pailin, western Cambodia. The pfmdr1 Y184F mutation was common, particularly in and around Cambodia, and the F1226Y mutation was found in about half of samples in Mae Sot. The functional significance of these two mutations remains unclear. Other previously documented pfmdr1 mutations were absent or very rare in the region. The pfcrt mutation K76T associated with chloroquine resistance was found in 98.2% of isolates. The CVIET haplotype made up 95% or more of isolates in western SEA while the CVIDT haplotype was common (30–40% of isolates) in north and northeastern Cambodia, southern Laos, and southern Vietnam. Conclusions These findings generate cause for concern regarding the mid-term efficacy of artemether–lumefantrine in Myanmar, while the absence of resistance-conferring pfmdr1 mutations and SVMNT pfcrt haplotypes suggests that amodiaquine could be an efficacious component of anti-malarial regimens in SEA. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1598-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Krongkan Srimuang
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Olivo Miotto
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.,Wellcome Trust Sanger Institute, Hinxton, UK.,Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Pharath Lim
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Dominic P Kwiatkowski
- Wellcome Trust Sanger Institute, Hinxton, UK.,Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Charles J Woodrow
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.
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10
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Zhong D, Wang X, Xu T, Zhou G, Wang Y, Lee MC, Hartsel JA, Cui L, Zheng B, Yan G. Effects of Microclimate Condition Changes Due to Land Use and Land Cover Changes on the Survivorship of Malaria Vectors in China-Myanmar Border Region. PLoS One 2016; 11:e0155301. [PMID: 27171475 PMCID: PMC4865052 DOI: 10.1371/journal.pone.0155301] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 04/27/2016] [Indexed: 02/06/2023] Open
Abstract
In the past decade, developing countries have been experiencing rapid land use and land cover changes, including deforestation and cultivation of previously forested land. However, little is known about the impact of deforestation and land-use changes on the life history of malaria vectors and their effects on malaria transmission. This study examined the effects of deforestation and crop cultivation on the adult survivorship of major malaria mosquitoes, Anopheles sinensis and An. minimus in the China-Myanmar border region. We examined three conditions: indoor, forested, and banana plantation. Mean survival time of An. sinensis in banana plantation environment was significantly longer than those in forested environment, and mosquitoes exhibited the longest longevity in the indoor environment. This pattern held for both males and females, and also for An. minimus. To further test the effect of temperature on mosquito survival, we used two study sites with different elevation and ambient temperatures. Significantly higher survivorship of both species was found in sites with lower elevation and higher ambient temperature. Increased vector survival in the deforested area could have an important impact on malaria transmission in Southeast Asia. Understanding how deforestation impacts vector survivorship can help combat malaria transmission.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, People's Republic of China
| | - Tielong Xu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Ying Wang
- Department of Pathogen Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, People's Republic of China
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Joshua A. Hartsel
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Liwang Cui
- Department of Entomology, the Pennsylvania State University, University Park, Pennsylvania, 16802, United States of America
| | - Bin Zheng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
- * E-mail:
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11
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Win AA, Imwong M, Kyaw MP, Woodrow CJ, Chotivanich K, Hanboonkunupakarn B, Pukrittayakamee S. K13 mutations and pfmdr1 copy number variation in Plasmodium falciparum malaria in Myanmar. Malar J 2016; 15:110. [PMID: 26911145 PMCID: PMC4765153 DOI: 10.1186/s12936-016-1147-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Accepted: 02/04/2016] [Indexed: 11/11/2022] Open
Abstract
Background Artemisinin-based combination therapy has been first-line treatment for falciparum malaria in Myanmar since 2005. The wide extent of artemisinin resistance in the Greater Mekong sub-region and the presence of mefloquine resistance at the Myanmar-Thailand border raise concerns over resistance patterns in Myanmar. The availability of molecular markers for resistance to both drugs enables assessment even in remote malaria-endemic areas. Methods A total of 250 dried blood spot samples collected from patients with Plasmodium falciparum malarial infection in five malaria-endemic areas across Myanmar were analysed for kelch 13 sequence (k13) and pfmdr1 copy number variation. K13 mutations in the region corresponding to amino acids 210–726 (including the propeller region of the protein) were detected by nested PCR amplification and sequencing, and pfmdr1 copy number variation by real-time PCR. In two sites, a sub-set of patients were prospectively followed up for assessment of day-3 parasite clearance rates after a standard course of artemether-lumefantrine. Results K13 mutations and pfmdr1 amplification were successfully analysed in 206 and 218 samples, respectively. Sixty-nine isolates (33.5 %) had mutations within the k13 propeller region with 53 of these (76.8 %) having mutations already known to be associated with artemisinin resistance. F446I (32 isolates) and P574L (15 isolates) were the most common examples. K13 mutation was less common in sites in western border regions (29 of 155 isolates) compared to samples from the east and north (40 of 51 isolates; p < 0.0001). The overall proportion of parasites with multiple pfmdr1 copies (greater than 1.5) was 5.5 %. Seven samples showed both k13 mutation and multiple copies of pfmdr1. Only one of 36 patients followed up after artemether-lumefantrine treatment still had parasites at day 3; molecular analysis indicated wild-type k13 and single copy pfmdr1. Conclusion The proportion of P. falciparum isolates with mutations in the propeller region of k13 indicates that artemisinin resistance extends across much of Myanmar. There is a low prevalence of parasites with multiple pfmdr1 copies across the country. The efficacy of artemisinin-based combination therapy containing mefloquine and lumefantrine is, therefore, expected to be high, although regular monitoring of efficacy will be important. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1147-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aye A Win
- Department of Medicine, Institute of Medicine 1, Yangon, Myanmar.
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand. .,Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.
| | - Myat P Kyaw
- Department of Medical Research (Lower Myanmar), Yangon, Myanmar.
| | - Charles J Woodrow
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine & Global Health, University of Oxford, Oxford, UK.
| | - Kesinee Chotivanich
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand. .,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Borimas Hanboonkunupakarn
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand. .,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Sasithon Pukrittayakamee
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand. .,Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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12
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Comparison of diagnostics for the detection of asymptomatic Plasmodium falciparum infections to inform control and elimination strategies. Nature 2015; 528:S86-93. [PMID: 26633770 DOI: 10.1038/nature16039] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The global burden of malaria has been substantially reduced over the past two decades. Future efforts to reduce malaria further will require moving beyond the treatment of clinical infections to targeting malaria transmission more broadly in the community. As such, the accurate identification of asymptomatic human infections, which can sustain a large proportion of transmission, is becoming a vital component of control and elimination programmes. We determined the relationship across common diagnostics used to measure malaria prevalence - polymerase chain reaction (PCR), rapid diagnostic test and microscopy - for the detection of Plasmodium falciparum infections in endemic populations based on a pooled analysis of cross-sectional data. We included data from more than 170,000 individuals comparing the detection by rapid diagnostic test and microscopy, and 30,000 for detection by rapid diagnostic test and PCR. The analysis showed that, on average, rapid diagnostic tests detected 41% (95% confidence interval = 26-66%) of PCR-positive infections. Data for the comparison of rapid diagnostic test to PCR detection at high transmission intensity and in adults were sparse. Prevalence measured by rapid diagnostic test and microscopy was comparable, although rapid diagnostic test detected slightly more infections than microscopy. On average, microscopy captured 87% (95% confidence interval = 74-102%) of rapid diagnostic test-positive infections. The extent to which higher rapid diagnostic test detection reflects increased sensitivity, lack of specificity or both, is unclear. Once the contribution of asymptomatic individuals to the infectious reservoir is better defined, future analyses should ideally establish optimal detection limits of new diagnostics for use in control and elimination strategies.
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13
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Survey of chloroquine-resistant mutations in the Plasmodium falciparum pfcrt and pfmdr-1 genes in Hadhramout, Yemen. Acta Trop 2015; 149:59-63. [PMID: 26001972 DOI: 10.1016/j.actatropica.2015.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 05/14/2015] [Accepted: 05/16/2015] [Indexed: 11/24/2022]
Abstract
Malaria is still a major public health problem in Yemen. More than 95% of the malaria cases are due to Plasmodium falciparum. Recently in Yemen, the antimalarial treatment policy was changed from chloroquine (CQ) to artemisinin combination therapy (ACTs). However, CQ is still available and prescribed in the Yemeni market. The persistence of CQ resistance will be prolonged if the shift to ACT and the simultaneous withdrawal of CQ are not rigorously implemented. The aim of the current survey is to detect chloroquine-resistant mutations in P. falciparum chloroquine-resistance transporter (pfcrt) and P. falciparum multi-drug resistance-1 (pfmdr1) genes. These data will be important for future monitoring and assessment of antimalarial drug policy in Yemen. Blood specimens were collected from 735 individuals from different districts of the Hadhramout province, Yemen by house-to-house visit. Mutation-specific nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) methods were used to investigate the mutations in the pfmdr1(codons 86 and 1246) and pfcrt (codons 76, 271, 326, 356 and 371) genes. The overall prevalence of pfcrt mutations at codons 76, 271, 326 and 371 were 50.4%, 58.7%, 54.3% and 44.9%, respectively. All isolates had wild-type pfcrt 356 allele. The majority of pfmdr1 86 alleles (83.3%) and all pfmdr1 1246 alleles were wild type. There was no association between pfcrt mutations and symptomatology, gender and age groups. In conclusion, point mutations in codons 76, 271, 326 and 371 of pfcrt of P. falciparum are high suggesting a sustained high CQ resistance even after 4 years of shifting to ACTs. These findings warrant complete withdrawal of CQ use from the Yemeni market for P. falciparum and careful usage of CQ for treating Plasmodium vivax.
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14
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Morris U, Xu W, Msellem MI, Schwartz A, Abass A, Shakely D, Cook J, Bhattarai A, Petzold M, Greenhouse B, Ali AS, Björkman A, Fröberg G, Mårtensson A. Characterising temporal trends in asymptomatic Plasmodium infections and transporter polymorphisms during transition from high to low transmission in Zanzibar, 2005-2013. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 33:110-7. [PMID: 25917493 PMCID: PMC10445533 DOI: 10.1016/j.meegid.2015.04.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/14/2015] [Accepted: 04/18/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Improved understanding of the asymptomatic malaria parasite reservoir is a prerequisite to pursue malaria elimination efforts. We therefore characterised temporal trends and transporter polymorphisms in asymptomatic Plasmodium infections during the transition from high to low transmission in Zanzibar. METHODS Healthy individuals participating in cross-sectional surveys conducted 2005-2013 were screened for asymptomatic malaria by PCR. Complexity/diversity of infection and transporter polymorphisms were assessed in Plasmodium falciparum positive samples. Symptomatic samples were included for comparison of polymorphisms in 2013. RESULTS PCR-determined parasite prevalence declined from 21.1% (CI95% 17.4-24.9) to 2.3% (CI95% 1.7-2.9) from 2005 to 2013. P. falciparum remained the predominant species; prevalence was highest in children and young adults aged 5-25 years. Parasite densities and complexity of infection, but not population genetic diversity of P. falciparum, decreased from 2005-2009. pfcrt 76T (99.2-64.7%, p < 0.001) and pfmdr1 86Y frequencies (89.4-66.7%, p = 0.03) decreased over time. Pfmdr1 (a.a.86,184,1246) YYY and YYD haplotypes were more frequent in asymptomatic than symptomatic infections in 2013 (p < 0.001). CONCLUSIONS There is a declining, albeit persistent, reservoir of parasites present at low-densities in asymptomatic individuals in Zanzibar. This study revealed important characteristics of the remaining parasite population, including intriguing temporal trends in molecular markers associated with antimalarial resistance, which need to be further investigated.
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Affiliation(s)
- Ulrika Morris
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Weiping Xu
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Mwinyi I Msellem
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Alanna Schwartz
- Department of Medicine, University of California San Francisco, CA, USA
| | - Ali Abass
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Delér Shakely
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Medicine, Kungälv Hospital, Kungälv, Sweden
| | - Jackie Cook
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Achuyt Bhattarai
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Max Petzold
- Health Metrics at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, CA, USA
| | - Abdullah S Ali
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Gabrielle Fröberg
- Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Mårtensson
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden; Centre for Clinical Research Sörmland, Uppsala University, Sweden
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15
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Feng XY, Xia ZG, Vong S, Yang WZ, Zhou SS. Surveillance and response to drive the national malaria elimination program. ADVANCES IN PARASITOLOGY 2015; 86:81-108. [PMID: 25476882 DOI: 10.1016/b978-0-12-800869-0.00004-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The national action plan for malaria elimination in China (2010-2020) was issued by the Chinese Ministry of Health along with other 13 ministries and commissions in 2010. The ultimate goal of the national action plan was to eliminate local transmission of malaria by the end of 2020. Surveillance and response are the most important components driving the whole process of the national malaria elimination programme (NMEP), under the technical guidance used in NMEP. This chapter introduces the evolution of the surveillance from the control to the elimination stages and the current structure of national surveillance system in China. When the NMEP launched, both routine surveillance and sentinel surveillance played critical role in monitoring the process of NMEP. In addition, the current response strategy of NMEP was also reviewed, including the generally developed "1-3-7 Strategy". More effective and sensitive risk assessment tools were introduced, which cannot only predict the trends of malaria, but also are important for the design and adjustment of the surveillance and response systems in the malaria elimination stage. Therefore, this review presents the landscape of malaria surveillance and response in China as well as their contribution to the NMEP, with a focus on activities for early detection of malaria cases, timely control of malaria foci and epidemics, and risk prediction. Furthermore, challenges and recommendations for accelerating NMEP through surveillance are put forward.
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Affiliation(s)
- Xin-Yu Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Key Laboratory of Parasite and Vector Biology, MOH; WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People's Republic of China
| | - Zhi-Gui Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Key Laboratory of Parasite and Vector Biology, MOH; WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People's Republic of China
| | - Sirenda Vong
- World Health Organization, China Representative Office, Beijing, People's Republic of China
| | - Wei-Zhong Yang
- Chinese Preventive Medicine Association, Beijing, People's Republic of China; Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Shui-Sen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Key Laboratory of Parasite and Vector Biology, MOH; WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People's Republic of China
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16
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Amplification of pfmdr1, pfcrt, pvmdr1, and K13 propeller polymorphisms associated with Plasmodium falciparum and Plasmodium vivax isolates from the China-Myanmar border. Antimicrob Agents Chemother 2015; 59:2554-9. [PMID: 25691632 DOI: 10.1128/aac.04843-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/05/2015] [Indexed: 02/02/2023] Open
Abstract
Malaria in the China-Myanmar border region is still severe; local transmission of both falciparum and vivax malaria persists, and there is a risk of geographically expanding antimalarial resistance. In this research, the pfmdr1, pfcrt, pvmdr1, and K13-propeller genotypes were determined in 26 Plasmodium falciparum and 64 Plasmodium vivax isolates from Yingjiang county of Yunnan province. The pfmdr1 (11.5%), pfcrt (34.6%), and pvmdr1 (3.1%) mutations were prevalent at the China-Myanmar border. The indigenous samples exhibited prevalences of 14.3%, 28.6%, and 14.3% for pfmdr1 N86Y, pfcrt K76T, and pfcrt M74I, respectively, whereas the samples from Myanmar showed prevalences of 10.5%, 21.1%, and 5.3%, respectively. The most prevalent genotypes of pfmdr1 and pfcrt were Y86Y184 and M74N75T76, respectively. No pvmdr1 mutation occurred in the indigenous samples but was observed in two cases coming from Myanmar. In addition, we are the first to report on 10 patients (38.5%) with five different K13 point mutations. The F446I allele is predominant (19.2%), and its prevalence was 28.6% in the indigenous samples of Yingjiang county and 15.8% in samples from Myanmar. The present data might be helpful for enrichment of the molecular surveillance of antimalarial resistance and useful for developing and updating guidance for the use of antimalarials in this region.
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17
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Zingani E, Inoue S, Muungo LTM. The current status of infrastructure for monitoring the efficacy of antimalarial therapeutics in Zambia. MALARIAWORLD JOURNAL 2014; 5:9. [PMID: 38764800 PMCID: PMC11100366 DOI: 10.5281/zenodo.10887816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Background Sub-Saharan countries have experienced centuries of high morbidity and mortality due to malaria. In addition to insecticide-treated mosquito nets and indoor residual spraying, modern antimalarial medicines have been developed to reduce disease prevalence, although the emergence of drug-resistant strains has compromised their efficacy. The purpose of this study was to evaluate the current status of malaria diagnosis and treatment, and to monitor the therapeutic efficacy of antimalarial drugs. Materials and Methods A descriptive cross-sectional survey was conducted from 2011 to 2013 at 10 district hospitals in Zambia designated as malaria sentinel sites as well as at the National Malaria Control Centre. District medical officers at each site completed interview questionnaires. Results Although basic infrastructure necessary for monitoring antimalarial drug resistance (such as laboratory, dispensary, admission ward, database unit, administration offices, bed space, examination and emergency rooms) was present at all sites, there was a shortage of licensed healthcare personnel. At some sites, antimalarial drugs were prescribed for malaria-like symptoms without diagnostic confirmation by blood smear. There was no regular monitoring of antimalarial drug resistance: only one trial was conducted among all sites in the previous 24 months. Conclusion A lack of antimalarial drug resistance monitoring might be associated with personnel and funding shortages. Additional financial support would be necessary to avoid the development and spread of drug-resistant malaria in Zambia.
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Affiliation(s)
- Ellah Zingani
- Department of Pharmacy, University of Zambia, School of Medicine, P.O. Box 50110, Lusaka, Zambia
| | - Satoshi Inoue
- Department of Biological Science and Nursing, Yokohama City University, School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Lungwani Tyson M. Muungo
- Department of Pharmacy, University of Zambia, School of Medicine, P.O. Box 50110, Lusaka, Zambia
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18
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Wang RB, Zhang J, Zhang QF. Malaria baseline survey in four special regions of northern Myanmar near China: a cross-sectional study. Malar J 2014; 13:302. [PMID: 25098412 PMCID: PMC4132201 DOI: 10.1186/1475-2875-13-302] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/31/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Epidemiological data in the border area of the northern Myanmar near China are either of little accuracy or sparse of information, due to the poor public health system in these areas, and malaria cases may be severely underestimated. This study aimed to investigate malaria prevalence and health facilities for malaria services, and to provide the baseline information for malaria control in these areas. METHODS A cluster, randomized, cross-sectional survey was conducted in four special regions of northern Myanmar, near China: 5,585 people were selected for a malaria prevalence survey and 1,618 households were selected for a mosquito net-owning survey. Meanwhile, a total of 97 health facilities were surveyed on their malaria services. The data were analysed and descriptive statistics were used. RESULTS A total of 761 people were found positive through microscopy test, including 290 people for Plasmodium falciparum, 460 for Plasmodium vivax, two for Plasmodium malariae, and nine for mixed infection. The average prevalence of malaria infection was 13.6% (95% CI: 12.7-14.6%). There were significant differences of prevalence of malaria infection among the different regions (P < 0.01); 38.1% (95% CI: 28.3-48.0%) of health facilities had malaria microscope examination service, and 35.1% (95% CI: 25.4-44.7%) of these had malaria treatment services, 23.7% (95% CI: 15.1-32.3%) had malaria outreach services. 28.3% (95% CI: 26.1-30.6%) of households owned one or more long-lasting insecticidal bed nets (LLINs). CONCLUSION The prevalence of malaria infection was high in the four special regions of northern Myanmar, near China. Malaria services in health facilities in these areas were weak. ITNs/LLINs owning rate was also low. The cross-border cooperation mechanism should be further strengthened to share the epidemical data about malaria, support technical assistance, and conduct joint malaria control or elimination activities.
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Affiliation(s)
- Ru-bo Wang
- 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, Shanghai 200025, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
| | - Jun Zhang
- Yunnan Office of Health Poverty Action (HPA), Kunming 650041, People’s Republic of China
| | - Qing-feng Zhang
- 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, Shanghai 200025, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, People’s Republic of China
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19
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Muhamad P, Chaijaroenkul W, Phompradit P, Rueangweerayut R, Tippawangkosol P, Na-Bangchang K. Polymorphic patterns of pfcrt and pfmdr1 in Plasmodium falciparum isolates along the Thai-Myanmar border. Asian Pac J Trop Biomed 2014; 3:931-5. [PMID: 24093782 DOI: 10.1016/s2221-1691(13)60181-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 10/21/2013] [Accepted: 11/20/2013] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVE To investigate the distribution and patterns of pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum (P. falciparum) isolates collected from the malaria endemic area of Thailand along Thai-Myanmar border. METHODS Dried blood spot samples were collected from 172 falciparum malaria patients prior received treatment. The samples were extracted using chelex to obtain parasite DNA. PCR-RFLP was employed to detect pfcrt mutation at codons 76, 220, 271, 326, 356 and 371, and the pfmdr1 mutation at codon 86. Pfmdr1 gene copy number was determined by SYBR Green I real-time PCR. RESULTS Mutant alleles of pfcrt and wild type allele of pfmdr1 were found in almost all samples. Pfmdr1 gene copy number in isolates collected from all areas ranged from 1.0 to 5.0 copies and proportion of isolates carrying>1 gene copies was 38.1%. The distribution and patterns of pfcrt and pfmdr1 mutations were similar in P. falciparum isolates from all areas. However, significant differences in both number of pfmdr1 copies and prevalence of isolates carrying>1 gene copies were observed among isolates collected from different areas. The median pfmdr1 copy number in P. falciparum collected from Kanchanaburi and Mae Hongson were 2.5 and 2.0, respectively and more than half of the isolates carried>1 gene copies. CONCLUSIONS The observation of pfmdr1 wild type and increasing of gene copy number may suggest declining of artesunate-mefloquine treatment efficacy in P. falciparum isolates in this border area.
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Affiliation(s)
- Phunuch Muhamad
- Chulabhorn International College of Medicine, Thammasat University, Patumthani, Thailand
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Haque U, Overgaard HJ, Clements ACA, Norris DE, Islam N, Karim J, Roy S, Haque W, Kabir M, Smith DL, Glass GE. Malaria burden and control in Bangladesh and prospects for elimination: an epidemiological and economic assessment. LANCET GLOBAL HEALTH 2014; 2:e98-105. [PMID: 25104666 DOI: 10.1016/s2214-109x(13)70176-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Malaria is endemic in 13 of 64 districts in Bangladesh. About 14 million people are at risk. Some evidence suggests that the prevalence of malaria in Bangladesh has decreased since the the Global Fund to Fight AIDS, Tuberculosis and Malaria started to support the National Malaria Control Program (NMCP) in 2007. We did an epidemiological and economic assessment of malaria control in Bangladesh. METHODS We obtained annually reported, district-level aggregated malaria case data and information about disbursed funds from the NMCP. We used a Poisson regression model to examine the associations between total malaria, severe malaria, malaria-attributable mortality, and insecticide-treated net coverage. We identified and mapped malaria hotspots using the Getis-Ord Gi* statistic. We estimated the cost-effectiveness of the NMCP by estimating the cost per confirmed case, cost per treated case, and cost per person of insecticide-treated net coverage. FINDINGS During the study period (from Jan 1, 2008, to Dec 31, 2012) there were 285,731 confirmed malaria cases. Malaria decreased from 6.2 cases per 1000 population in 2008, to 2.1 cases per 1000 population in 2012. Prevalence of all malaria decreased by 65% (95% CI 65-66), severe malaria decreased by 79% (78-80), and malaria-associated mortality decreased by 91% (83-95). By 2012, there was one insecticide-treated net for every 2.6 individuals (SD 0.20). Districts with more than 0.5 insecticide-treated nets per person had a decrease in prevalence of 21% (95% CI 19-23) for all malaria, 25% (17-32) for severe malaria, and 76% (35-91) for malaria-associated mortality among all age groups. Malaria hotspots remained in the highly endemic districts in the Chittagong Hill Tracts. The cost per diagnosed case was US$0.39 (SD 0.02) and per treated case was $0.51 (0.27); $0.05 (0.04) was invested per person per year for health education and $0.68 (0.30) was spent per person per year for insecticide-treated net coverage. INTERPRETATION Malaria elimination is an achievable prospect in Bangladesh and failure to push for elimination nearly ensures a resurgence of disease. Consistent financing is needed to avoid resurgence and maintain elimination goals. FUNDING None.
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Affiliation(s)
- Ubydul Haque
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Hans J Overgaard
- Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Archie C A Clements
- University of Queensland, Infectious Disease Epidemiology Unit, School of Population Health, Herston, QLD, Australia
| | - Douglas E Norris
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Nazrul Islam
- Ministry of Health and Family Welfare, Malaria and Parasitic Disease Control, Director General of Health Services, Mohakhali, Dhaka, Bangladesh
| | - Jahirul Karim
- Ministry of Health and Family Welfare, Malaria and Parasitic Disease Control, Director General of Health Services, Mohakhali, Dhaka, Bangladesh
| | - Shyamal Roy
- Ministry of Health and Family Welfare, Malaria and Parasitic Disease Control, Director General of Health Services, Mohakhali, Dhaka, Bangladesh
| | - Waziul Haque
- Oslo and Akershus University College of Applied Sciences, Oslo, Norway
| | - Moktadir Kabir
- BRAC Health, Nutrition and Population Programme, BRAC, Dhaka, Bangladesh
| | - David L Smith
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Gregory E Glass
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; Southern Research Institute, Frederick, MD, USA
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Starzengruber P, Fuehrer HP, Ley B, Thriemer K, Swoboda P, Habler VE, Jung M, Graninger W, Khan WA, Haque R, Noedl H. High prevalence of asymptomatic malaria in south-eastern Bangladesh. Malar J 2014; 13:16. [PMID: 24406220 PMCID: PMC3896725 DOI: 10.1186/1475-2875-13-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/22/2013] [Indexed: 12/23/2022] Open
Abstract
Background The WHO has reported that RDT and microscopy-confirmed malaria cases have declined in recent years. However, it is still unclear if this reflects a real decrease in incidence in Bangladesh, as particularly the hilly and forested areas of the Chittagong Hill Tract (CHT) Districts report more than 80% of all cases and deaths. surveillance and epidemiological data on malaria from the CHT are limited; existing data report Plasmodium falciparum and Plasmodium vivax as the dominant species. Methods A cross-sectional survey was conducted in the District of Bandarban, the southernmost of the three Hill Tracts Districts, to collect district-wide malaria prevalence data from one of the regions with the highest malaria endemicity in Bangladesh. A multistage cluster sampling technique was used to collect blood samples from febrile and afebrile participants and malaria microscopy and standardized nested PCR for diagnosis were performed. Demographic data, vital signs and splenomegaly were recorded. Results Malaria prevalence across all subdistricts in the monsoon season was 30.7% (95% CI: 28.3-33.2) and 14.2% (95% CI: 12.5-16.2) by PCR and microscopy, respectively. Plasmodium falciparum mono-infections accounted for 58.9%, P. vivax mono-infections for 13.6%, Plasmodium malariae for 1.8%, and Plasmodium ovale for 1.4% of all positive cases. In 24.4% of all cases mixed infections were identified by PCR. The proportion of asymptomatic infections among PCR-confirmed cases was 77.0%, oligosymptomatic and symptomatic cases accounted for only 19.8 and 3.2%, respectively. Significantly (p < 0.01) more asymptomatic cases were recorded among participants older than 15 years as compared to younger participants, whereas prevalence and parasite density were significantly (p < 0.01) higher in patients younger than 15 years. Spleen rate and malaria prevalence in two to nine year olds were 18.6 and 34.6%, respectively. No significant difference in malaria prevalence and parasite density was observed between dry and rainy season. Conclusions A large proportion of asymptomatic plasmodial infections was found which likely act as a reservoir of transmission. This has major implications for ongoing malaria control programmes that are based on the treatment of symptomatic patients. These findings highlight the need for new intervention strategies targeting asymptomatic carriers.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Harald Noedl
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Kinderspitalgasse 15, Vienna 1090, Austria.
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Li N, Parker DM, Yang Z, Fan Q, Zhou G, Ai G, Duan J, Lee MC, Yan G, Matthews SA, Cui L, Wang Y. Risk factors associated with slide positivity among febrile patients in a conflict zone of north-eastern Myanmar along the China-Myanmar border. Malar J 2013; 12:361. [PMID: 24112638 PMCID: PMC3852943 DOI: 10.1186/1475-2875-12-361] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 09/21/2013] [Indexed: 12/02/2022] Open
Abstract
Background Malaria within the Greater Mekong sub-region is extremely heterogeneous. While China and Thailand have been relatively successful in controlling malaria, Myanmar continues to see high prevalence. Coupled with the recent emergence of artemisinin-resistant malaria along the Thai-Myanmar border, this makes Myanmar an important focus of malaria within the overall region. However, accurate epidemiological data from Myanmar have been lacking, in part because of ongoing and emerging conflicts between the government and various ethnic groups. Here the results are reported from a risk analysis of malaria slide positivity in a conflict zone along the China-Myanmar border. Methods Surveys were conducted in 13 clinics and hospitals around Laiza City, Myanmar between April 2011 and October 2012. Demographic, occupational and educational information, as well as malaria infection history, were collected. Logistic models were used to assess risk factors for slide positivity. Results Age patterns in Plasmodium vivax infections were younger than those with Plasmodium falciparum. Furthermore, males were more likely than females to have falciparum infections. Patients who reported having been infected with malaria during the previous year were much more likely to have a current vivax infection. During the second year of the study, falciparum infections among soldiers increased signficiantly. Conclusions These results fill some knowledge gaps with regard to risk factors associated with malaria slide positivity in this conflict region of north-eastern Myanmar. Since epidemiological studies in this region have been rare or non-existent, studies such as the current are crucial for understanding the dynamic nature of malaria in this extremely heterogeneous epidemiological landscape.
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Affiliation(s)
- Nana Li
- Department of Tropical Disease, Institute of Tropical Medicine, Third Military Medical University, Chongqing, China.
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