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Nyunt MH, Hlaing T, Oo HW, Tin-Oo LLK, Phway HP, Wang B, Zaw NN, Han SS, Tun T, San KK, Kyaw MP, Han ET. Molecular assessment of artemisinin resistance markers, polymorphisms in the k13 propeller, and a multidrug-resistance gene in the eastern and western border areas of Myanmar. Clin Infect Dis 2014; 60:1208-15. [PMID: 25537878 DOI: 10.1093/cid/ciu1160] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND As K13 propeller mutations have been recently reported to serve as molecular markers, assessment of K13 propeller polymorphisms in multidrug-resistant gene in isolates from Myanmar, especially the eastern and western border areas, is crucial if we are to understand the spread of artemisinin resistance. METHODS A 3-day surveillance study was conducted in the eastern and western border areas in Myanmar, and K13 propeller and Plasmodium falciparum multidrug resistance-associated protein 1 (pfmrp1) mutations were analyzed. RESULTS Among the 1761 suspected malaria cases screened, a total of 42 uncomplicated falciparum cases from the eastern border and 49 from the western border were subjected to 3 days of surveillance after artemether-lumefantrine treatment. No parasitemic case showing positivity on day 3 was noted from the western border, but 26.2% (11/42) of cases were positive in the eastern border. Although we found no marked difference in the prevalence of the pfmrp1 mutation in the eastern and western borders (36% vs 31%, respectively), K13 mutations were more frequent in the eastern border area (where the 3-day persistent cases were detected; 48% vs 14%). C580Y, M476I, A481V, N458Y, R539T, and R516Y accounted for 68.9% of all K13 mutations significantly associated with day 3 parasitaemia. CONCLUSIONS The K13 mutations were significantly associated with day 3 parasitaemia, emphasizing the importance of K13 surveillance. The low prevalence of K13 mutations and the absence of day 3 parasitaemic cases indicate that artemisinin resistance may not have spread to the western Myanmar border region. Although analysis of multiple K13 mutations is challenging, it should be done at various sentinel sites in Myanmar.
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Affiliation(s)
- Myat Htut Nyunt
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Thaung Hlaing
- Department of Health, Nay Pyi Taw, Republic of the Union of Myanmar
| | - Htet Wai Oo
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Lu-Lu Kyaw Tin-Oo
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Hnin Phyu Phway
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Bo Wang
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Ni Ni Zaw
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Soe Soe Han
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Thurein Tun
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Kyaw Kyaw San
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Myat Phone Kyaw
- Department of Medical Research (Lower Myanmar), Yangon, Republic of the Union of Myanmar
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
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Brown TS, Jacob CG, Silva JC, Takala-Harrison S, Djimdé A, Dondorp AM, Fukuda M, Noedl H, Nyunt MM, Kyaw MP, Mayxay M, Hien TT, Plowe CV, Cummings MP. Plasmodium falciparum field isolates from areas of repeated emergence of drug resistant malaria show no evidence of hypermutator phenotype. Infect Genet Evol 2014; 30:318-322. [PMID: 25514047 DOI: 10.1016/j.meegid.2014.12.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/04/2014] [Accepted: 12/07/2014] [Indexed: 11/30/2022]
Abstract
Multiple transcontinental waves of drug resistance in Plasmodium falciparum have originated in Southeast Asia before spreading westward, first into the rest of Asia and then to sub-Saharan Africa. In vitro studies have suggested that hypermutator P. falciparum parasites may exist in Southeast Asia and that an increased rate of acquisition of new mutations in these parasites may explain the repeated emergence of drug resistance in Southeast Asia. This study is the first to test the hypermutator hypothesis using field isolates. Using genome-wide SNP data from human P. falciparum infections in Southeast Asia and West Africa and a test for relative rate differences we found no evidence of increased relative substitution rates in P. falciparum isolates from Southeast Asia. Instead, we found significantly increased substitution rates in Mali and Bangladesh populations relative to those in populations from Southeast Asia. Additionally we found no association between increased relative substitution rates and parasite clearance following treatment with artemisinin derivatives.
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Affiliation(s)
- Tyler S Brown
- Johns Hopkins University School of Medicine, Baltimore, MD, USA; Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christopher G Jacob
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joana C Silva
- Institute for Genome Sciences and Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shannon Takala-Harrison
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Abdoulaye Djimdé
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Pharmacy, University of Science, Techniques and Technology of Bamako, Bamako, Mali
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Center for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
| | - Mark Fukuda
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Harald Noedl
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria and Malaria Research Initiative Bandarban, Bandarban, Bangladesh
| | - Myaing Myaing Nyunt
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Myat Phone Kyaw
- Department of Medical Research (Lower Myanmar), Yangon, Myanmar
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao Democratic People's Republic; Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao Democratic People's Republic
| | - Tran Tinh Hien
- Centre for Tropical Medicine Oxford University Clinical Research Unit Vietnam (OUCRU), Ho Chi Minh City, Viet Nam
| | - Christopher V Plowe
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michael P Cummings
- Laboratory of Molecular Evolution, Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, USA.
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Wai KT, Kyaw MP, Oo T, Zaw P, Nyunt MH, Thida M, Kyaw TT. Spatial distribution, work patterns, and perception towards malaria interventions among temporary mobile/migrant workers in artemisinin resistance containment zone. BMC Public Health 2014; 14:463. [PMID: 24884534 PMCID: PMC4032392 DOI: 10.1186/1471-2458-14-463] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 05/12/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Mobile populations are at a high risk of malaria infection and suspected to carry and spread resistant parasites. The Myanmar National Malaria Control Programme focuses on preventive interventions and vector control measures for the temporary mobile/migrant workers in Myanmar Artemisinin Resistance Containment Zones. METHODS A prospective cross-sectional study was conducted in 2012 in Kawthaung and Bokepyin townships of Tanintharyi Region, Myanmar, covering 192 mobile/migrant aggregates. The objectives were to identify the spatial distribution of the mobile/migrant populations, and to assess knowledge, attitudes, perceptions, and practices concerning malaria prevention and control, and their preferred methods of interventions. The structure of the 192 migrant aggregates was investigated using a migrant mapping tool. Individual and household information was collected by structured interviews of 408 respondents from 39 aggregates, supplemented by 12 in-depth interviews of health care providers, authorities, volunteers, and employers. Data were analyzed by triangulating quantitative and qualitative data. RESULTS The primary reasons for the limitation in access to formal health services for suspected malaria within 24 hours were identified to be scattered distribution of migrant aggregates, variable working hours and the lack of transportation. Only 19.6% of respondents reported working at night from dusk to dawn. Among study populations, 73% reported a perceived risk of contracting malaria and 60% reported to know how to confirm a suspected case of malaria. Moreover, only 15% was able to cite correct antimalarial drugs, and less than 10% believed that non-compliance with antimalarial treatment may be related to the risk of drug resistance. About 50% of study population reported to seeking health care from the public sector, and to sleep under ITNs/LLINs the night before the survey. There was a gap in willingness to buy ITNs/LLINs and affordability (88.5% vs. 60.2%) which may affect their sustained and consistent use. Only 32.4% across all aggregates realized the importance of community participation in effective malaria prevention and control. CONCLUSIONS Community-based innovative approaches through strong collaboration and coordination of multi-stakeholders are desirable for relaying information on ITNs/LLINs, rapid diagnostic test, and artemisinin combination therapy and drug resistance successfully across the social and economic diversity of mobile/migrant aggregates in Myanmar.
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Affiliation(s)
- Khin Thet Wai
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - Myat Phone Kyaw
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - Tin Oo
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - PeThet Zaw
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - Myat Htut Nyunt
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - Moe Thida
- Department of Medical Research (Lower Myanmar), No. 5 Ziwaka Road, 11191 Yangon, Myanmar
| | - Thar Tun Kyaw
- Department of Health, National Malaria Control Programme, Nay Pyi Taw, Myanmar
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Miao M, Wang Z, Yang Z, Yuan L, Parker DM, Putaporntip C, Jongwutiwes S, Xangsayarath P, Pongvongsa T, Moji H, Dinh Tuong T, Abe T, Nakazawa S, Kyaw MP, Yan G, Sirichaisinthop J, Sattabongkot J, Mu J, Su XZ, Kaneko O, Cui L. Genetic diversity and lack of artemisinin selection signature on the Plasmodium falciparum ATP6 in the Greater Mekong Subregion. PLoS One 2013; 8:e59192. [PMID: 23555629 PMCID: PMC3608609 DOI: 10.1371/journal.pone.0059192] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/12/2013] [Indexed: 11/30/2022] Open
Abstract
The recent detection of clinical Artemisinin (ART) resistance manifested as delayed parasite clearance in the Cambodia-Thailand border area raises a serious concern. The mechanism of ART resistance is not clear; but the P. falciparum sarco/endoplasmic reticulum Ca2+-ATPase (PfSERCA or PfATP6) has been speculated to be the target of ARTs and thus a potential marker for ART resistance. Here we amplified and sequenced pfatp6 gene (∼3.6 Kb) in 213 samples collected after 2005 from the Greater Mekong Subregion, where ART drugs have been used extensively in the past. A total of 24 single nucleotide polymorphisms (SNPs), including 8 newly found in this study and 13 nonsynonymous, were identified. However, these mutations were either uncommon or also present in other geographical regions with limited ART use. None of the mutations were suggestive of directional selection by ARTs. We further analyzed pfatp6 from a worldwide collection of 862 P. falciparum isolates in 19 populations from Asia, Africa, South America and Oceania, which include samples from regions prior to and after deployments ART drugs. A total of 71 SNPs were identified, resulting in 106 nucleotide haplotypes. Similarly, many of the mutations were continent-specific and present at frequencies below 5%. The most predominant and perhaps the ancestral haplotype occurred in 441 samples and was present in 16 populations from Asia, Africa, and Oceania. The 3D7 haplotype found in 54 samples was the second most common haplotype and present in nine populations from all four continents. Assessment of the selection strength on pfatp6 in the 19 parasite populations found that pfatp6 in most of these populations was under purifying selection with an average dN/dS ratio of 0.333. Molecular evolution analyses did not detect significant departures from neutrality in pfatp6 for most populations, challenging the suitability of this gene as a marker for monitoring ART resistance.
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Affiliation(s)
- Miao Miao
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Zenglei Wang
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Zhaoqing Yang
- Parasitology Department, Kunming Medical College, Kunming, Yunnan, China
| | - Lili Yuan
- Parasitology Department, Kunming Medical College, Kunming, Yunnan, China
| | - Daniel M. Parker
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Chaturong Putaporntip
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Chulalongkorn University, Bangkok, Thailand
| | - Somchai Jongwutiwes
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Chulalongkorn University, Bangkok, Thailand
| | - Phonepadith Xangsayarath
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program, Nagasaki University, Japan
| | - Tiengkham Pongvongsa
- Station of Malariology, Parasitology and Entomology, North Phonesavang Village, Kaysone District, Savannakhet Province, Laos
| | - Hazuhiko Moji
- Research Institute for Humanity and Nature, Kyoto, Japan
| | - Trinh Dinh Tuong
- Department of Epidemiology, National Institute of Malariology, Parasitology, and Entomology, Hanoi, Vietnam
| | - Tomoko Abe
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program, Nagasaki University, Japan
| | - Shusuke Nakazawa
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program, Nagasaki University, Japan
| | - Myat Phone Kyaw
- Parasitology Research Division, Department of Medical Research-Lower Myanmar, Yangon, Myanmar
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
| | | | | | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xin-zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN) and the Global Center of Excellence program, Nagasaki University, Japan
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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55
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Cui L, Yan G, Sattabongkot J, Cao Y, Chen B, Chen X, Fan Q, Fang Q, Jongwutiwes S, Parker D, Sirichaisinthop J, Kyaw MP, Su XZ, Yang H, Yang Z, Wang B, Xu J, Zheng B, Zhong D, Zhou G. Malaria in the Greater Mekong Subregion: heterogeneity and complexity. Acta Trop 2012. [PMID: 21382335 DOI: 10.1016/j.actatropica.2011.02.016.malaria] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
Abstract
The Greater Mekong Subregion (GMS), comprised of six countries including Cambodia, China's Yunnan Province, Lao PDR, Myanmar (Burma), Thailand and Vietnam, is one of the most threatening foci of malaria. Since the initiation of the WHO's Mekong Malaria Program a decade ago, malaria situation in the GMS has greatly improved, reflected in the continuous decline in annual malaria incidence and deaths. However, as many nations are moving towards malaria elimination, the GMS nations still face great challenges. Malaria epidemiology in this region exhibits enormous geographical heterogeneity with Myanmar and Cambodia remaining high-burden countries. Within each country, malaria distribution is also patchy, exemplified by 'border malaria' and 'forest malaria' with high transmission occurring along international borders and in forests or forest fringes, respectively. 'Border malaria' is extremely difficult to monitor, and frequent malaria introductions by migratory human populations constitute a major threat to neighboring, malaria-eliminating countries. Therefore, coordination between neighboring countries is essential for malaria elimination from the entire region. In addition to these operational difficulties, malaria control in the GMS also encounters several technological challenges. Contemporary malaria control measures rely heavily on effective chemotherapy and insecticide control of vector mosquitoes. However, the spread of multidrug resistance and potential emergence of artemisinin resistance in Plasmodium falciparum make resistance management a high priority in the GMS. This situation is further worsened by the circulation of counterfeit and substandard artemisinin-related drugs. In most endemic areas of the GMS, P. falciparum and Plasmodium vivax coexist, and in recent malaria control history, P. vivax has demonstrated remarkable resilience to control measures. Deployment of the only registered drug (primaquine) for the radical cure of vivax malaria is severely undermined due to high prevalence of glucose-6-phosphate dehydrogenase deficiency in target human populations. In the GMS, the dramatically different ecologies, diverse vector systems, and insecticide resistance render traditional mosquito control less efficient. Here we attempt to review the changing malaria epidemiology in the GMS, analyze the vector systems and patterns of malaria transmission, and identify the major challenges the malaria control community faces on its way to malaria elimination.
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Affiliation(s)
- Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, 16801, USA.
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56
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Cui L, Yan G, Sattabongkot J, Cao Y, Chen B, Chen X, Fan Q, Fang Q, Jongwutiwes S, Parker D, Sirichaisinthop J, Kyaw MP, Su XZ, Yang H, Yang Z, Wang B, Xu J, Zheng B, Zhong D, Zhou G. Malaria in the Greater Mekong Subregion: heterogeneity and complexity. Acta Trop 2012; 121:227-39. [PMID: 21382335 DOI: 10.1016/j.actatropica.2011.02.016] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 02/18/2011] [Accepted: 02/26/2011] [Indexed: 10/18/2022]
Abstract
The Greater Mekong Subregion (GMS), comprised of six countries including Cambodia, China's Yunnan Province, Lao PDR, Myanmar (Burma), Thailand and Vietnam, is one of the most threatening foci of malaria. Since the initiation of the WHO's Mekong Malaria Program a decade ago, malaria situation in the GMS has greatly improved, reflected in the continuous decline in annual malaria incidence and deaths. However, as many nations are moving towards malaria elimination, the GMS nations still face great challenges. Malaria epidemiology in this region exhibits enormous geographical heterogeneity with Myanmar and Cambodia remaining high-burden countries. Within each country, malaria distribution is also patchy, exemplified by 'border malaria' and 'forest malaria' with high transmission occurring along international borders and in forests or forest fringes, respectively. 'Border malaria' is extremely difficult to monitor, and frequent malaria introductions by migratory human populations constitute a major threat to neighboring, malaria-eliminating countries. Therefore, coordination between neighboring countries is essential for malaria elimination from the entire region. In addition to these operational difficulties, malaria control in the GMS also encounters several technological challenges. Contemporary malaria control measures rely heavily on effective chemotherapy and insecticide control of vector mosquitoes. However, the spread of multidrug resistance and potential emergence of artemisinin resistance in Plasmodium falciparum make resistance management a high priority in the GMS. This situation is further worsened by the circulation of counterfeit and substandard artemisinin-related drugs. In most endemic areas of the GMS, P. falciparum and Plasmodium vivax coexist, and in recent malaria control history, P. vivax has demonstrated remarkable resilience to control measures. Deployment of the only registered drug (primaquine) for the radical cure of vivax malaria is severely undermined due to high prevalence of glucose-6-phosphate dehydrogenase deficiency in target human populations. In the GMS, the dramatically different ecologies, diverse vector systems, and insecticide resistance render traditional mosquito control less efficient. Here we attempt to review the changing malaria epidemiology in the GMS, analyze the vector systems and patterns of malaria transmission, and identify the major challenges the malaria control community faces on its way to malaria elimination.
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57
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Baker J, Ho MF, Pelecanos A, Gatton M, Chen N, Abdullah S, Albertini A, Ariey F, Barnwell J, Bell D, Cunningham J, Djalle D, Echeverry DF, Gamboa D, Hii J, Kyaw MP, Luchavez J, Membi C, Menard D, Murillo C, Nhem S, Ogutu B, Onyor P, Oyibo W, Wang SQ, McCarthy J, Cheng Q. Global sequence variation in the histidine-rich proteins 2 and 3 of Plasmodium falciparum: implications for the performance of malaria rapid diagnostic tests. Malar J 2010; 9:129. [PMID: 20470441 PMCID: PMC2893195 DOI: 10.1186/1475-2875-9-129] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 05/17/2010] [Indexed: 11/20/2022] Open
Abstract
Background Accurate diagnosis is essential for prompt and appropriate treatment of malaria. While rapid diagnostic tests (RDTs) offer great potential to improve malaria diagnosis, the sensitivity of RDTs has been reported to be highly variable. One possible factor contributing to variable test performance is the diversity of parasite antigens. This is of particular concern for Plasmodium falciparum histidine-rich protein 2 (PfHRP2)-detecting RDTs since PfHRP2 has been reported to be highly variable in isolates of the Asia-Pacific region. Methods The pfhrp2 exon 2 fragment from 458 isolates of P. falciparum collected from 38 countries was amplified and sequenced. For a subset of 80 isolates, the exon 2 fragment of histidine-rich protein 3 (pfhrp3) was also amplified and sequenced. DNA sequence and statistical analysis of the variation observed in these genes was conducted. The potential impact of the pfhrp2 variation on RDT detection rates was examined by analysing the relationship between sequence characteristics of this gene and the results of the WHO product testing of malaria RDTs: Round 1 (2008), for 34 PfHRP2-detecting RDTs. Results Sequence analysis revealed extensive variations in the number and arrangement of various repeats encoded by the genes in parasite populations world-wide. However, no statistically robust correlation between gene structure and RDT detection rate for P. falciparum parasites at 200 parasites per microlitre was identified. Conclusions The results suggest that despite extreme sequence variation, diversity of PfHRP2 does not appear to be a major cause of RDT sensitivity variation.
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Affiliation(s)
- Joanne Baker
- Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia.
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58
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Htut Y, Aye KH, Han KT, Kyaw MP, Shimono K, Okada S. Feasibility and limitations of acridine orange fluorescence technique using a Malaria Diagnosis Microscope in Myanmar. Acta Med Okayama 2002; 56:219-22. [PMID: 12530504 DOI: 10.18926/amo/31709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
We studied parasite detectability in thick films by an acridine orange fluorescence technique (AO) to test its applicability and the use of a Malaria Diagnosis Microscope (MDM)-ESL in the detection of parasites, compared to the conventional Giemsa staining method. This study was conducted on 1,390 clinically suspected malaria cases of Thaton township, Myanmar. We found sensitivities of 82.8% for Plasmodium falciparum (P. falciparum) and 100% for Plasmodium vivax (P. vivax) and specificities of 97.1% for P. falciparum and 98.6% for P. vivax. AO had a higher sensitivity than Giemsa-stained films at low levels of parasitemia (< 1,000/microl). AO showed lower sensitivity and higher specificity than the Giemsa method at parasite levels of more than 1,000/microl. The results of using the AO method, achieved by both novice and experienced observers, showed no significant difference and required less practice to perform the test as well as to identify the parasite. The acridine orange fluorescence technique using a malaria diagnosis microscope MDM-ESL series is simple, rapid and cost effective. The microscope is conveniently operable using standard AC power or a 12-V DC car battery, and it is easily convertible to a conventional biological microscope. With the exception of species differentiation, which is not possible with this method, this method would be appropriate for both clinical and epidemiological studies.
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Affiliation(s)
- Ye Htut
- Parasitology Research Division, Department of Medical Research (Lower Myanmar), No. 5, Ziwaka Road, Yangon 11191, Myanmar
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59
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Lwin M, Aung S, Kyaw MP, Aung H, Sint N, Win Y, Oo H, Thein H, Tun SM. A simplified in vivo drug sensitivity test for malaria in the field. Southeast Asian J Trop Med Public Health 1997; 28:247-53. [PMID: 9444001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The study was intended to develop a simple and reliable in vivo field test for monitoring of sensitivity of P.falciparum to antimalarials. The test is to be used as a built in sustainable monitoring system and applied at regular frequencies to provide guidance in developing a country-wide antimalarial drug policy. The study was conducted as a hospital based study in Mon State in Mudon, Kamawet and Pa-auk hospitals. The criteria matched malaria patients were treated with standard dosages of chloroquine, sulfadoxine-pyrimethamine and mefloquine and blood films were taken on days 0, 2, 3, 4, 7, 14 and 28. The assessment of the in vivo drug response of P.falciparum on days 2, 3 and 4 were compared with WHO standard 28 days and 7 day tests. The following successful tests were carried out for 7 days with different antimalarials: 171 tests with chloroquine and sulfadoxine-pyrimethamine and 167 tests with mefloquine. Tests were also carried out for 28 days: 59 tests with chloroquine, 77 tests with sulfadoxine-pyrimethamine and 78 tests with mefloquine. The results found that 3 day tests, taking blood films on days 0 and 3, can be reliably used as an adjunct to 28-day tests. Since the test is simple and can be used extensively and sustainably throughout the country and the results are applicable to be used for epidemiological purposes, the method is suggested for use as a built-in monitoring method for the malaria control program.
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Affiliation(s)
- M Lwin
- Department of Medical Research, Ministry of Health, Yangon, Myanmar
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60
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Lwin M, Lin H, Linn N, Kyaw MP, Ohn M, Maung NS, Soe K, Oo T. The use of personal protective measures in control of malaria in a defined community. Southeast Asian J Trop Med Public Health 1997; 28:254-8. [PMID: 9444002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Malaria is one of the main health problems in the non-immune immigrant workers and army personnel of the malaria endemic areas in Myanmar. Due to changes in the vector bionomics and multiresistant strains of P. falciparum, chemoprophylaxis alone is not an effective means of control of malaria in them. So it is envisaged that the combined used of personal protective measures (deltamethrin impregnated bed-nets, scalves and hand-bands) and the chemoprophylaxis will be an effective means of control of malaria in the define group of people. The study also intended to find out the side effects of the deltamethrin and feasibility and acceptability of methods by the users. The study was conducted in Theini Township, Northern Shan State, from March to November 1993. The study population consisted of all ages of both sexes 554 and 440 persons in the test and control groups respectively. At the initial phase of the study, malaria infected persons from both the groups were treated. The experimental group received personal protective measures with impregnation of bed-nets using 25 mg ai/m2 of deltamethrin at 4 monthly intervals and the scarves and hand-bands at twice the concentration of the insecticides at monthly intervals. Chemoprophylaxis was given to both the groups at weekly intervals using age adjusted dosage of Pyrixine tablet (sulfadoxine-pyrimethamine). The parasitological, entomological, and epidemiological indices were collected at two month intervals in both the groups. The study clearly showed the impact of personal protective measures and chemoprophylaxis on malaria infection in the studied subjects. During the study period, the out patient malaria cases of the test group was 6% to 11.2% and that of the control group was 12% to 21.6% in Theini Hospital. The reinfection rate of the test group (0.9 to 4.7%) was also significantly lower than the control group (6.1 to 14.3%) from July to November. Acceptance of the treated bed-nets, scarves and hand-bands was high and good compliance was found in the follow up. The results of the study clearly showed that malaria can be controlled effectively in the defined group of persons for a malaria transmission season by using chemoprophylaxis and personal protective measures.
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Affiliation(s)
- M Lwin
- Disease Control Unit, Department of Health, Ministry of Defence, Yangon, Myanmar
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