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Cáceres Carrera L, Santamaría AM, Castillo AM, Romero L, Urriola E, Torres-Cosme R, Calzada JE. Detection through the use of RT-MqPCR of asymptomatic reservoirs of malaria in samples of patients from the indigenous Comarca of Guna Yala, Panama: Essential method to achieve the elimination of malaria. PLoS One 2024; 19:e0305558. [PMID: 39046959 PMCID: PMC11268588 DOI: 10.1371/journal.pone.0305558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 06/02/2024] [Indexed: 07/27/2024] Open
Abstract
BACKGROUND Plasmodium vivax is the main causative agent of malaria in Panama. However, the prevalence of asymptomatic infections in the different endemic regions remains unknown. Understanding the epidemiological behavior of asymptomatic infections is essential for the elimination of malaria. This study aimed to determine the prevalence of asymptomatic malarial infections in one of the main endemic regions of Panama using multiplex real-time reverse transcription RT-MqPCR. METHODS A cross-sectional study was conducted in three communities in the Guna Yala Comarca. A total of 551 thick blood smears and their respective samples on filter paper were collected from volunteers of different ages and sexes from June 20 to 25, 2016. Infections by the Plasmodium spp. were diagnosed using microscopy and RT-MqPCR. All statistical analyses were performed using the R software. RESULTS The average prevalence of asymptomatic infections by P. vivax in the three communities detected by RT-MqPCR was 9.3%, with Ukupa having the highest prevalence (13.4%), followed by Aidirgandi (11.1%) and Irgandi (3.3%). A total of 74 samples were diagnosed as asymptomatic infections using RT-MqPCR. Light microscopy (LM) detected that 17.6% (13/74) of the asymptomatic samples and 82.4% (61/74) were diagnosed as false negatives. A 100% correlation was observed between samples diagnosed using LM and RT-MqPCR. A total of 52.7% (39/74) of the asymptomatic patients were female and 85.1% (63/74) were registered between the ages of 1 and 21 years. Factors associated with asymptomatic infection were community (aOR = 0.38 (95% CI 0.17-0.83), p < 0.001) and age aOR = 0.98 (95% CI 0.97-1.00), p < 0.05); F = 5.38; p < 0.05). CONCLUSIONS This study provides novel evidence of the considerable prevalence of asymptomatic P. vivax infections in the endemic region of Kuna Yala, representing a new challenge that requires immediate attention from the National Malaria Program. The results of this study provide essential information for the health authorities responsible for developing new policies. Furthermore, it will allow program administrators to reorient and design effective malaria control strategies that consider asymptomatic infections as a fundamental part of malaria control and move towards fulfilling their commitment to eliminate it.
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Affiliation(s)
- Lorenzo Cáceres Carrera
- Departmento de Entomología Médica del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
| | - Ana María Santamaría
- Departmento de Parasitología del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
| | - Anakena Margarita Castillo
- Departmento de Entomología Médica del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
| | - Luis Romero
- Laboratorio Central de Referencia en Salud Pública del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
| | - Eduardo Urriola
- Facultad de Ciencias Biomédicas, Universidad Latina de Panamá, Ciudad de Panamá, Panamá
| | - Rolando Torres-Cosme
- Departmento de Entomología Médica del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
| | - José Eduardo Calzada
- Departmento de Parasitología del Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá
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Malla P, Wang Z, Brashear A, Yang Z, Lo E, Baird K, Wang C, Cui L. Effectiveness of an Unsupervised Primaquine Regimen for Preventing Plasmodium vivax Malaria Relapses in Northeast Myanmar: A Single-Arm Nonrandomized Observational Study. J Infect Dis 2024; 229:1557-1564. [PMID: 38041857 PMCID: PMC11095535 DOI: 10.1093/infdis/jiad552] [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: 05/21/2023] [Revised: 11/16/2023] [Accepted: 11/29/2023] [Indexed: 12/04/2023] Open
Abstract
BACKGROUND Plasmodium vivax presents a significant challenge for malaria elimination in the Greater Mekong Subregion. We evaluated the effectiveness of primaquine for reducing relapses of vivax malaria. METHODS Patients with uncomplicated P vivax malaria from eastern Myanmar received chloroquine (25-mg base/kg given in 3 days) plus unsupervised PQ (0.25 mg/kg/d for 14 days) without screening for glucose-6-phosphate dehydrogenase deficiency and were followed for a year. RESULTS A total of 556 patients were enrolled to receive the chloroquine/primaquine treatment from February 2012 to August 2013. During the follow-up, 38 recurrences were detected, presenting a cumulative recurrence rate of 9.1% (95% CI, 4.1%-14.1%). Genotyping at the pvmsp1 and pvmsp3α loci by amplicon deep sequencing and model prediction indicated that 13 of the 27 recurrences with genotyping data were likely due to relapses. Notably, all confirmed relapses occurred within the first 6 months. CONCLUSIONS The unsupervised standard dose of primaquine was highly effective as a radical cure for P vivax malaria in eastern Myanmar. The high presumed effectiveness might have benefited from the health messages delivered during the enrollment and follow-up activities. Six-month follow-ups in the Greater Mekong Subregion are sufficient for detecting most relapses.
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Affiliation(s)
- Pallavi Malla
- Department of Internal Medicine, Morsani College of Medicine
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa
| | - Zenglei Wang
- MHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Beijing Union Medical College
| | - Awtum Brashear
- Department of Internal Medicine, Morsani College of Medicine
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, China
| | - Eugenia Lo
- Department of Microbiology and Immunology, College of Medicine, Drexel University
| | - Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine
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Zhao X, Hu Y, Zhao Y, Wang L, Wu Z, Soe MT, Kyaw MP, Cui L, Zhu X, Cao Y. Genetic diversity in the transmission-blocking vaccine candidate Plasmodium vivax gametocyte protein Pvs230 from the China-Myanmar border area and central Myanmar. Parasit Vectors 2022; 15:371. [PMID: 36253843 PMCID: PMC9574792 DOI: 10.1186/s13071-022-05523-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sexual stage surface antigens are potential targets of transmission-blocking vaccines (TBVs). The gametocyte and gamete surface antigen P230, a leading TBV candidate, is critical for red blood cell binding during exflagellation and subsequent oocyst development. Here, the genetic diversity of Pvs230 was studied in Plasmodium vivax parasite isolates from the China-Myanmar border (CMB) and central Myanmar. METHODS Plasmodium vivax isolates were collected in clinics from malaria-endemic areas of the CMB (143 samples) and Myanmar (23 samples). The interspecies variable part (IVP, nucleotides 1-807) and interspecies conserved part (ICP, 808-2862) of Pvs230 were amplified by PCR and sequenced. Molecular evolution studies were conducted to evaluate the genetic diversity, signature of selection, population differentiation, haplotype network, and population structure of the study parasite populations and publicly available Pvs230 sequences from six global P. vivax populations. RESULTS Limited genetic diversity was observed for the CMB (π = 0.002) and Myanmar (π = 0.001) isolates. Most amino acid substitutions were located in the IVP and cysteine-rich domain of Pvs230. Evidence of positive selection was observed for IVP and purifying selection for ICP. Codon-based tests identified specific codons under natural selection in both IVP and ICP. The fixation index (FST) showed low genetic differentiation between East and Southeast Asian populations, with FST ranging from 0.018 to 0.119. The highest FST value (FST = 0.503) was detected between the Turkey and Papua New Guinea populations. A total of 92 haplotypes were identified in global isolates, with the major haplotypes 2 and 9 being the most abundant and circulating in East and Southeast Asia populations. Several detected non-synonymous substitutions were mapped in the predicted structure and B-cell epitopes of Pvs230. CONCLUSIONS We detected low levels of genetic diversity of Pvs230 in global P. vivax populations. Geographically specific haplotypes were identified for Pvs230. Some mutations are located within a potential B-cell epitope region and need to be considered in future TBV designs.
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Affiliation(s)
- Xin Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yubing Hu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.,Central Laboratory of the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Lin Wang
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Zifang Wu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | | | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.
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Cui L, Sattabongkot J, Aung PL, Brashear A, Cao Y, Kaewkungwal J, Khamsiriwatchara A, Kyaw MP, Lawpoolsri S, Menezes L, Miao J, Nguitragool W, Parker D, Phuanukoonnon S, Roobsoong W, Siddiqui F, Soe MT, Sriwichai P, Yang Z, Zhao Y, Zhong D. Multidisciplinary Investigations of Sustained Malaria Transmission in the Greater Mekong Subregion. Am J Trop Med Hyg 2022; 107:138-151. [PMID: 36228909 DOI: 10.4269/ajtmh.21-1267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/28/2022] [Indexed: 11/07/2022] Open
Abstract
In the course of malaria elimination in the Greater Mekong Subregion (GMS), malaria epidemiology has experienced drastic spatiotemporal changes with residual transmission concentrated along international borders and the rising predominance of Plasmodium vivax. The emergence of Plasmodium falciparum parasites resistant to artemisinin and partner drugs renders artemisinin-based combination therapies less effective while the potential spread of multidrug-resistant parasites elicits concern. Vector behavioral changes and insecticide resistance have reduced the effectiveness of core vector control measures. In recognition of these problems, the Southeast Asian International Center of Excellence for Malaria Research (ICEMR) has been conducting multidisciplinary research to determine how human migration, antimalarial drug resistance, vector behavior, and insecticide resistance sustain malaria transmission at international borders. These efforts allow us to comprehensively understand the ecology of border malaria transmission and develop population genomics tools to identify and track parasite introduction. In addition to employing in vivo, in vitro, and molecular approaches to monitor the emergence and spread of drug-resistant parasites, we also use genomic and genetic methods to reveal novel mechanisms of antimalarial drug resistance of parasites. We also use omics and population genetics approaches to study insecticide resistance in malaria vectors and identify changes in mosquito community structure, vectorial potential, and seasonal dynamics. Collectively, the scientific findings from the ICEMR research activities offer a systematic view of the factors sustaining residual malaria transmission and identify potential solutions to these problems to accelerate malaria elimination in the GMS.
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Affiliation(s)
- Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | | | | | - Awtum Brashear
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, China
| | | | | | | | | | - Lynette Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Mahidol University, Bangkok, Thailand
| | - Daniel Parker
- Department of Epidemiology, University of California at Irvine, Irvine, California
| | | | | | - Faiza Siddiqui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | - Patchara Sriwichai
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Yan Zhao
- Department of Immunology, China Medical University, Shenyang, China
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, California
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5
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Aung PL, Soe MT, Oo TL, Aung KT, Lin KK, Thi A, Menezes L, Parker DM, Cui L, Kyaw MP. Spatiotemporal dynamics of malaria in Banmauk Township, Sagaing region of Northern Myanmar: characteristics, trends, and risk factors. BMC Infect Dis 2022; 22:653. [PMID: 35902825 PMCID: PMC9331130 DOI: 10.1186/s12879-022-07634-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 07/19/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND While national malaria incidence has been declining in Myanmar, some subregions within the nation continue to have high burdens of malaria morbidity and mortality. This study assessed the malaria situation in one of these regions, Banmauk Township, located near the Myanmar-India border. Our goal was to provide a detailed description of the malaria epidemiology in this township and to provide some evidence-based recommendations to formulate a strategy for reaching the national malaria elimination plan. Banmauk consistently has one of the highest malaria burdens in Myanmar. METHODS With the implementation of strengthened malaria control and surveillance activities after the endorsement of a national malaria elimination plan in 2015, detailed incidence data were obtained for 2016-2018 for Banmauk Township. The data include patient demographics, parasite species, disease severity, and disease outcome. Data were analyzed to identify characteristics, trends, distribution, and risk factors. RESULTS During 2016-2018, 2,402 malaria cases were reported, with Plasmodium falciparum accounting for 83.4% of infections. Both P. falciparum and P. vivax were transmitted more frequently during the rainy season (May-October). Despite intensified control, the annual parasite incidence rate (API) in 2017 (11.0) almost doubled that in 2016 (6.5). In total, 2.5% (59/2042) of the cases, of which 54 P. falciparum and 5 P. vivax, were complicated cases, resulting in 5 deaths. Malaria morbidity was high in children < 15 years and accounted for 33.4% of all cases and about 47% of the complicated cases. Older age groups and males living with poor transportation conditions were more likely to test positive especially in rainy and cold seasons. Despite the clear seasonality of malaria, severe cases were found among young children even more common in the dry season, when malaria incidence was low. CONCLUSIONS Despite the declining trend, the malaria burden remained high in Banmauk Township. Our study also documented severe cases and deaths from both falciparum and vivax malaria. P. falciparum remained the predominant parasite species, demanding increased efforts to achieve the goal of elimination of P. falciparum by 2025. As P. falciparum cases decreased, the proportion of cases attributable to P. vivax increased. In order to eliminate malaria, it will likely be important to increasingly target this species as well.
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Affiliation(s)
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | - Thit Lwin Oo
- Myanmar Health Network Organization, Yangon, Myanmar
| | - Kyaw Thu Aung
- Township Health Department, Banmauk Township, Sagaing, Myanmar
| | - Kyaw Kyaw Lin
- Township Health Department, Banmauk Township, Sagaing, Myanmar
| | - Aung Thi
- Department of Public Health, Ministry of Health, NayPyiTaw, Myanmar
| | - Lynette Menezes
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Daniel M Parker
- Department of Population Health and Disease Prevention, University of California, Irvine, CA, USA.
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA.
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6
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Cui YB, Shen HM, Chen SB, Kassegne K, Shi TQ, Xu B, Chen JH, Wu JH, Wang Y. Genetic Diversity and Selection of Plasmodium vivax Apical Membrane Antigen-1 in China-Myanmar Border of Yunnan Province, China, 2009-2016. Front Cell Infect Microbiol 2022; 11:742189. [PMID: 35071030 PMCID: PMC8766981 DOI: 10.3389/fcimb.2021.742189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/09/2021] [Indexed: 11/26/2022] Open
Abstract
Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is an important vaccine candidate for vivax malaria. However, antigenic variation within PvAMA-1 is a major obstacle to the design of a global protective malaria vaccine. In this study, we analyzed the genetic polymorphism and selection of the PvAMA-1 gene from 152 P. vivax isolates from imported cases to China, collected in the China–Myanmar border (CMB) area in Yunnan Province (YP) during 2009–2011 (n = 71) and 2014–2016 (n = 81), in comparison with PvAMA-1 gene information from Myanmar (n = 73), collected from public data. The overall nucleotide diversity of the PvAMA-1 gene from the 152 YP isolates was 0.007 with 76 haplotypes identified (Hd = 0.958). Results from the population structure suggested three groups among the YP and Myanmar isolates with optimized clusters value of K = 7. In addition, YP (2014–2016) isolates generally lacked some K components that were commonly found in YP (2009–2011) and Myanmar. Meanwhile, PvAMA-1 domain I is found to be the dominant target of positive diversifying selection and most mutation loci were found in this domain. The mutation frequencies of D107N/A, R112K/T, K120R, E145A, E277K, and R438H in PvAMA-1 were more than 70% in the YP isolates. In conclusion, high genetic diversity and positive selection were found in the PvAMA-1 gene from YP isolates, which are significant findings for the design and development of PvAMA-1-based malaria vaccine.
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Affiliation(s)
- Yan-Bing Cui
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Kokouvi Kassegne
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tian-Qi Shi
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Bin Xu
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China.,School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Hong Wu
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, China.,Department of Parasitology, Provincial Key Laboratory of Modern Pathogen Biology, Guizhou Medical University, Guiyang, China
| | - Yue Wang
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
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Yang H, Wang J, Liu H, Zhao Y, Lakshmi S, Li X, Nie R, Li C, Wang H, Cao Y, Menezes L, Cui L. Efficacy and Safety of a Naphthoquine-Azithromycin Coformulation for Malaria Prophylaxis in Southeast Asia: A Phase 3, Double-blind, Randomized, Placebo-controlled Trial. Clin Infect Dis 2021; 73:e2470-e2476. [PMID: 32687174 DOI: 10.1093/cid/ciaa1018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A prophylactic antimalarial drug that is both effective for protection and improves compliance is in high demand. METHODS We conducted a randomized, placebo-controlled, double-blinded phase 3 trial to evaluate the 1:1 fixed-dose combination of naphthoquine-azithromycin (NQAZ) for safety and protection against Plasmodium infections in villages along the China-Myanmar border. A total of 631 residents, 5-65 years of age, were randomized into the drug group (n = 319) and the placebo group (n = 312) to receive NZAQ and placebo, respectively, as a single-dose monthly treatment. Follow-ups were conducted weekly to monitor for adverse events and malaria infections. RESULTS Of the 531 subjects completing the trial, there were 46 and 3 blood smear-positive Plasmodium infections in the placebo and treatment groups, respectively. For the intent-to-treat analysis, the single-dose monthly NQAZ treatment had 93.62% protective efficacy (95% confidence interval [CI]: 91.72%-95.52%). For the per-protocol analysis, NQAZ treatment provided a 93.04% protective efficacy (95% CI: 90.98%-95.1%). Three smear-positive cases in the NQAZ group were all due to acute falciparum malaria. In comparison, NQAZ treatment provided 100% protection against the relapsing malaria Plasmodium vivax and Plasmodium ovale. The treatment group had 5.6% of participants experiencing transient elevation of liver aminotransferases compared with 2.2% in the placebo group (P > .05). CONCLUSIONS Monthly prophylaxis with NQAZ tablets was well tolerated and highly effective for preventing Plasmodium infections. It may prove useful for eliminating P. vivax in areas with a high prevalence of glucose-6-phosphate dehydrogenase deficiency in the population. CLINICAL TRIALS REGISTRATION ChiCTR1800020140.
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Affiliation(s)
- Henglin Yang
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Jingyan Wang
- Institute of Microbiology and Epidemiology, Chinese Academy of Military Medical Sciences, Beijing, China
| | - Hui Liu
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Seetha Lakshmi
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Xingliang Li
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Renhua Nie
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Chunfu Li
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Hengye Wang
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Center of Malaria Research, Pu'er, Yunnan, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Lynette Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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8
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Cheng B, Htoo SN, Mhote NPP, Davison CM. Association between biological sex and insecticide-treated net use among household members in ethnic minority and internally displaced populations in eastern Myanmar. PLoS One 2021; 16:e0252896. [PMID: 34143807 PMCID: PMC8213136 DOI: 10.1371/journal.pone.0252896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
Malaria prevalence in Myanmar is highest among remote and ethnic minority populations living near forest fringes along the country’s international borders. Insecticide-treated nets (ITNs) are a key intervention used to prevent malaria transmission, but insufficient ITN availability and low use can hinder effectiveness. This study assessed age and sex disparities in ITN possession, access, and use among household members of ethnic minority and internally displaced populations in eastern Myanmar. Cross-sectional data from the 2013 Eastern Burma Retrospective Mortality Survey were used to describe prevalence of ITN possession, access, and use. The association between a household member’s biological sex and their ITN use was assessed using multilevel log binomial regression. Age and household ITN supply were tested as potential effect modifiers. Of 37927 household members, 89.8% (95% CI: 89.5, 90.1) of people lived in households with at least one ITN. Approximately half belonged to households with sufficient ITN supply and used an ITN. Pregnant women and children under five had the highest proportion of ITN use regardless of sufficient household ITN status. Female adults aged 15 to 49 years old (Risk ratio or RR: 1.4, 95% CI: 1.29, 1.52) were more likely to use ITNs. This relationship did not differ by sufficient household ITN status. The findings suggest that among ethnic minority populations in areas where ITN use is indicated, many households do not have adequate ITN supply, and many individuals are not using ITNs. Children under five and pregnant women appear to be prioritized for ITN use and overall, women are slightly more likely to use ITNs than men. This study’s findings can support efforts ensuring that all household members belonging to ethnic minority and displaced populations in Eastern Myanmar benefit from sufficient ITN access and use for malaria prevention.
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Affiliation(s)
- Breagh Cheng
- Department of Public Health Sciences, Queen’s University, Kingston, Ontario, Canada
| | | | | | - Colleen M. Davison
- Department of Public Health Sciences, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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Li Y, Hu Y, Zhao Y, Wang Q, Ngassa Mbenda HG, Kittichai V, Lawpoolsri S, Sattabongkot J, Menezes L, Liu X, Cui L, Cao Y. Dynamics of Plasmodium vivax populations in border areas of the Greater Mekong sub-region during malaria elimination. Malar J 2020; 19:145. [PMID: 32268906 PMCID: PMC7140319 DOI: 10.1186/s12936-020-03221-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 04/03/2020] [Indexed: 12/18/2022] Open
Abstract
Background Countries within the Greater Mekong Sub-region (GMS) of Southeast Asia have committed to eliminating malaria by 2030. Although the malaria situation has greatly improved, malaria transmission remains at international border regions. In some areas, Plasmodium vivax has become the predominant parasite. To gain a better understanding of transmission dynamics, knowledge on the changes of P. vivax populations after the scale-up of control interventions will guide more effective targeted control efforts. Methods This study investigated genetic diversity and population structures in 206 P. vivax clinical samples collected at two time points in two international border areas: the China-Myanmar border (CMB) (n = 50 in 2004 and n = 52 in 2016) and Thailand-Myanmar border (TMB) (n = 50 in 2012 and n = 54 in 2015). Parasites were genotyped using 10 microsatellite markers. Results Despite intensified control efforts, genetic diversity remained high (HE = 0.66–0.86) and was not significantly different among the four populations (P > 0.05). Specifically, HE slightly decreased from 0.76 in 2004 to 0.66 in 2016 at the CMB and increased from 0.80 in 2012 to 0.86 in 2015 at the TMB. The proportions of polyclonal infections varied significantly among the four populations (P < 0.05), and showed substantial decreases from 48.0% in 2004 to 23.7 at the CMB and from 40.0% in 2012 to 30.7% in 2015 at the TMB, with corresponding decreases in the multiplicity of infection. Consistent with the continuous decline of malaria incidence in the GMS over time, there were also increases in multilocus linkage disequilibrium, suggesting more fragmented and increasingly inbred parasite populations. There were considerable genetic differentiation and sub-division among the four tested populations. Temporal genetic differentiation was observed at each site (FST = 0.081 at the CMB and FST = 0.133 at the TMB). Various degrees of clustering were evident between the older parasite samples collected in 2004 at the CMB and the 2016 CMB and 2012 TMB populations, suggesting some of these parasites had shared ancestry. In contrast, the 2015 TMB population was genetically distinctive, which may reflect a process of population replacement. Whereas the effective population size (Ne) at the CMB showed a decrease from 4979 in 2004 to 3052 in 2016 with the infinite allele model, the Ne at the TMB experienced an increase from 6289 to 10,259. Conclusions With enhanced control efforts on malaria, P. vivax at the TMB and CMB showed considerable spatial and temporal differentiation, but the presence of large P. vivax reservoirs still sustained genetic diversity and transmission. These findings provide new insights into P. vivax transmission dynamics and population structure in these border areas of the GMS. Coordinated and integrated control efforts on both sides of international borders are essential to reach the goal of regional malaria elimination.
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Affiliation(s)
- Yuling Li
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.,Emergency Department, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, Liaoning, China
| | - Yubing Hu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Huguette Gaelle Ngassa Mbenda
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Veerayuth Kittichai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Saranath Lawpoolsri
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lynette Menezes
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Xiaoming Liu
- Center for Global Health and Infectious Disease Research, College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA. .,Center for Global Health and Infectious Disease Research, College of Public Health, University of South Florida, 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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10
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Zeng W, Malla P, Xu X, Pi L, Zhao L, He X, He Y, Menezes LJ, Cui L, Yang Z. Associations among Soil-Transmitted Helminths, G6PD Deficiency and Asymptomatic Malaria Parasitemia, and Anemia in Schoolchildren from a Conflict Zone of Northeast Myanmar. Am J Trop Med Hyg 2020; 102:851-856. [PMID: 32043453 DOI: 10.4269/ajtmh.19-0828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In tropical areas of developing countries, the interactions among parasitic diseases such as soil-transmitted helminths (STHs) and malaria, and glucose-6-phosphate dehydrogenase deficiency (G6PDd), are complex. Here, we investigated their interactions and impact on anemia in school students residing in a conflict zone of northeast Myanmar. A cross-sectional survey was conducted between July and December 2015 in two schools located along the China-Myanmar border. Stool samples from the schoolchildren were analyzed for STH infections, whereas finger-prick blood samples were analyzed for G6PDd, hemoglobin concentrations, and Plasmodium infections. Among 988 enrolled children, Plasmodium vivax, Plasmodium falciparum, hookworm, Ascaris lumbricoides, and Trichuris trichiura infections occurred in 3.3%, 0.8%, 31.5%, 1.2%, and 0.3%, respectively. Glucose-6-phosphate dehydrogenase deficiency was present in 16.9% of the children, and there was a very high prevalence of anemia (73%). Anthropometric measures performed on all children showed that 50% of the children were stunted and 25% wasted. Moderate to severe anemia was associated with STH infections, stunting, and wasting. In addition, children had increasing odds of anemia with increasing burden of infections. This study revealed a high prevalence of G6PDd, STHs, and anemia in schools located in a conflict zone. In areas where malnutrition and STH infections are rampant, testing for both glucose-6-phosphate dehydrogenase and anemia should be considered before treating vivax malaria with 8-aminoquinolines.
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Affiliation(s)
- Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Pallavi Malla
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Xin Xu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Liang Pi
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Luyi Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Xi He
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Yongshu He
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, China
| | - Lynette J Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
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11
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Yi H, Li H, Liang L, Wu Y, Zhang L, Qiu W, Jiang W, Yang F, Li Q, Yang Z, Wang C, Cui L, He Y. The glucose-6-phosphate dehydrogenase Mahidol variant protects against uncomplicated Plasmodium vivax infection and reduces disease severity in a Kachin population from northeast Myanmar. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2019; 75:103980. [PMID: 31351234 PMCID: PMC6832843 DOI: 10.1016/j.meegid.2019.103980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 07/08/2019] [Accepted: 07/24/2019] [Indexed: 01/19/2023]
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common red cell disorders in the world. The aim of this study was to investigate whether the G6PD Mahidol variant and haplotype 1311 T/93C, which are prevalent in the Kachin ethnic population along the China-Myanmar border area, offer protection against Plasmodium vivax infection. Malaria was monitored in nine villages near the Laiza township, Kachin State, Myanmar, where 258 cases of uncomplicated P. vivax were identified in 2013-2017. From the same villages, 250 unrelated, malaria-free participants were recruited to serve as the control cohort. Quantitative enzyme activity analysis in 100 healthy individuals identified that both male hemizygotes and female heterozygotes of the G6PD Mahidol variant had on average ~40% lower enzyme activity relative to the wild-type individuals. Compared with the overall prevalence of 25.2% in the control cohort, the G6PD Mahidol variant had a significantly lower prevalence (7.0%) among the 258 vivax patients (P < .0001, χ2 test). Logistic regression analysis of G6PD genotypes stratified by sex showed that the individuals with the Mahidol 487A allele had dramatically reduced odds of having acute vivax malaria (adjusted odds ratio = 0.213 for male 487A hemizygotes, P < .0001, and 0.248 for female 487GA heterozygotes, P < .001). Furthermore, both 487A hemizygous male and 487GA heterozygous female patients had significantly lower asexual parasitemias than the wild-type patients, suggesting a potential effect on alleviating disease severity. In contrast, the silent mutation haplotype 1311 T/93C was highly prevalent (49.6%) in the study population, but it was not associated with altered G6PD enzymatic activities nor did it seem to provide protection against vivax infection or disease severity. Taken together, this study provided evidence that the Mahidol G > A mutation offers protection against P. vivax infection and potentially reduces disease severity in a Kachin population.
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Affiliation(s)
- Haoan Yi
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Hong Li
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Luxin Liang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Yanrui Wu
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Lu Zhang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Wanfang Qiu
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Weiyang Jiang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Fang Yang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Qing Li
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China
| | - Chengqi Wang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA.
| | - Yongshu He
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China.
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12
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Geng J, Malla P, Zhang J, Xu S, Li C, Zhao Y, Wang Q, Kyaw MP, Cao Y, Yang Z, Cui L. Increasing trends of malaria in a border area of the Greater Mekong Subregion. Malar J 2019; 18:309. [PMID: 31514740 PMCID: PMC6739967 DOI: 10.1186/s12936-019-2924-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/17/2019] [Indexed: 11/27/2022] Open
Abstract
Background Intensive malaria transmission along international borders is a significant impediment to malaria elimination in the Greater Mekong Subregion (GMS) of Southeast Asia. Passive case detection (PCD) was used to study the dynamics and trends of malaria transmission at the China–Myanmar border to provide epidemiologic information for improved malaria control. Methods PCD was conducted in one hospital and 12 clinics near the Laiza town in northeast Myanmar from 2011 to 2016. Clinical malaria was diagnosed by microscopy and demographic information was captured using a structured questionnaire at the time of the patient’s presentation for care. Results Over the study period, 6175 (19.7%) malaria cases were confirmed by microscopy from 31,326 suspected cases. The four human malaria parasite species were all identified, with Plasmodium vivax and Plasmodium falciparum accounting for 5607 (90.8%) and 481 (7.8%) of the confirmed cases, respectively. In contrast to the steady decline of malaria in the general GMS, the study site had an upward trend of malaria incidence with vivax malaria outbreaks in 2013 and 2016. Adult males, children under the age of 15, and those with occupations such as farming, being a soldier or student, had significantly higher risks of clinical malaria compared to having fevers from other aetiologies. A self-reported history of clinical malaria was also associated with a higher risk of confirmed malaria. Conclusions The China–Myanmar border area has experienced an overall upward trend of malaria incidence in recent years with P. vivax becoming the predominant species. Evidence-based control strategies need to focus on high-risk populations.
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Affiliation(s)
- Jinting Geng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Pallavi Malla
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Shiling Xu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Cuiying Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | | | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China.
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA.
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13
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Randomized, Double-Blind, Placebo-Controlled Studies to Assess Safety and Prophylactic Efficacy of Naphthoquine-Azithromycin Combination for Malaria Prophylaxis in Southeast Asia. Antimicrob Agents Chemother 2018; 62:AAC.00793-18. [PMID: 29987144 DOI: 10.1128/aac.00793-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/05/2018] [Indexed: 01/01/2023] Open
Abstract
New prophylactic drugs against malaria infections are urgently needed. We conducted randomized, double-blind, placebo-controlled, phase 2 trials of a new antimalarial drug combination, naphthoquine-azithromycin (NQAZ), to determine its safety and protective efficacy in a low-endemicity area of Southeast Asia. In the first trial, 127 healthy volunteers were randomized to receive two single doses of either 400 mg of NQAZ (200 mg of each drug), 800 mg of NQAZ (400 mg of each drug), or placebo on day 0 and day 30. Weekly follow-ups were performed for 2 months, and physical and clinical laboratory exams were done during the second and eighth week. Both drug regimens were well tolerated, without any serious adverse events. Four adverse events (transient and slight elevations of serum transaminase concentrations) were found only in the two drug-treated groups and thus might be drug-related. In the second trial, 353 volunteer villagers were randomized into the same three groups as in the first trial, and malaria infections were followed for a month. For the intention-to-treat analysis, both regimens offered greater than 90% prophylactic efficacies against all malaria infections. When the analysis was done according to parasite species, 400 mg and 800 mg NQAZ provided 81.63 and 90.59% prophylactic efficacies, respectively, against Plasmodium falciparum infections, whereas both offered 100% prophylactic efficacy against Plasmodium vivax and Plasmodium ovale These trials showed that NQAZ had a good safety profile, and monthly single doses of 400 mg or 800 mg for adults offered excellent prophylaxis against malaria infections, especially the two relapsing species.
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14
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Zhao Y, Zeng J, Zhao Y, Liu Q, He Y, Zhang J, Yang Z, Fan Q, Wang Q, Cui L, Cao Y. Risk factors for asymptomatic malaria infections from seasonal cross-sectional surveys along the China-Myanmar border. Malar J 2018; 17:247. [PMID: 29973194 PMCID: PMC6032786 DOI: 10.1186/s12936-018-2398-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Border malaria, a shared phenomenon in the Greater Mekong Sub-region of Southeast Asia, is a major obstacle for regional malaria elimination. Along the China-Myanmar border, an additional problem arose as a result of the settlement of internally displaced people (IDP) in the border region. Since asymptomatic malaria significantly impacts transmission dynamics, assessment of the prevalence, dynamics and risk factors of asymptomatic malaria infections is necessary. METHODS Cross-sectional surveys were carried out in 3 seasons (March and April, July and November) and 2 sites (villages and IDP camps) in 2015. A total of 1680 finger-prick blood samples were collected and used for parasite detection by microscopy and nested RT-PCR (nRT-PCR). Logistic regression models were used to explore the risk factors associated with asymptomatic malaria at individual and household levels. RESULTS The prevalence of asymptomatic Plasmodium infections was 23.3% by nRT-PCR, significantly higher than that detected by microscopy (1.5%). The proportions of Plasmodium vivax, Plasmodium falciparum and mixed-species infections were 89.6, 8.1 and 2.3%, respectively. Asymptomatic infections showed obvious seasonality with higher prevalence in the rainy season. Logistic regression analysis identified males and school children (≤ 15 years) as the high-risk populations. Vector-based interventions, including bed net and indoor residual spray, were found to have significant impacts on asymptomatic Plasmodium infections, with non-users of these measures carrying much higher risks of infection. In addition, individuals living in poorly constructed households or farther away from clinics were more prone to asymptomatic infections. CONCLUSIONS Sub-microscopic Plasmodium infections were highly prevalent in the border human populations from IDP camps and surrounding villages. Both individual- and household-level risk factors were identified, which provides useful information for identifying the high-priority populations to implement targeted malaria control.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jie Zeng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yonghong Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yang He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China. .,Department of Entomology, Pennsylvania State University, University Park, State College, PA, 16802, USA.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
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15
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Liu H, Xu JW, Xu QZ, Zeng YR. Retrospective analysis of risk factors of slide positivity among febrile patients in the Salween river valley of Shan Special Region II, northern Myanmar. BMC Public Health 2018; 18:560. [PMID: 29703185 PMCID: PMC5924485 DOI: 10.1186/s12889-018-5469-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 04/17/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In Myanmar, epidemiological conditions have been unclear due to a lack of accurate data. In 2014 and 2016, malaria outbreaks occurred in the Shan Special Region II (SSR2). It was reported that these outbreaks were caused by malaria patients from the Salween River Valley (SRV), but further research is needed to confirm these reports. To examine the risks of malaria infection in the SSR2 section of the SRV, this paper offers a retrospective analysis based on the data we collected in 2009. METHODS A multivariate logistic model was utilized to analyze risk factors associated with the slide positivity of 2009. Results of the investigation in 2009 were compared with updated data. RESULTS The number of slide positivity was 91 (24.7%, 95% confidence interval [CI], 20.3-29.4%) among 369 people who had fever 2 weeks ago of the survey, including 74 (20.1%; 95%CI, 16.1-24.5%) cases of P. falciparum, 13 (3.5%; 95%CI, 1.9-5.9%) of P.vivax and 4 (1.1%, 95%CI, 0.3-2.8%) of P. malariae. The adjusted odds ratio (OR) was 99.8 (95% CI, 24.7-887.7) for patients' age < 15 years, 6.61 (95%CI, 3.57-10.49) for people living at an altitude of < 800 m, 6.35 (95%CI, 2.45-23.27) for people lacking knowledge on malaria transmission and knowledge on symptoms, 2.10 (95%CI, 1.22-5.11) for people taking no measures against mosquito bites and 5.55 (95%CI, 2.65-13.05) for people delaying treatment. Compared with annual parasitic incidences 13.80 per 10,000 person-years (422/305733) in 2014, 2.36 per 10,000 person-years (73/309004) in 2015 and 5.25 per 10,000 person-years (164/312310) in 2015, malaria burden is reduced. CONCLUSION Age, lower altitude, a lack of knowledge about malaria transmission and symptoms, inaction of measures against mosquito bites and delayed treatment-seeking were independent risk factors for slide positivity. These results indicate that malaria transmission was likely within housing settlements in the SRV, and that the transmission rates within the SRV are higher than in other areas. In order to eliminate malaria, it is important for people to obtain qualified treatment to contain artemisinin resistance. TRIAL REGISTRATION Trial registration number: ChiCTR-COC-17012522 . Retrospectively registered 31 August 2017.
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Affiliation(s)
- Hui Liu
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Collaborative Innovation Center for Public Health and Disease Prevention and Control, Puer, 665000, China
| | - Jian-Wei Xu
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Collaborative Innovation Center for Public Health and Disease Prevention and Control, Puer, 665000, China.
| | - Qi-Zhang Xu
- People's Hospital of Taikang County, Taikang, 475400, Henan Province, China
| | - Yi-Rou Zeng
- Mengmao County Hospital, Mengmao, Shan Special Region II, Myanmar
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16
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Xu X, Zhou G, Wang Y, Hu Y, Ruan Y, Fan Q, Yang Z, Yan G, Cui L. Microgeographic Heterogeneity of Border Malaria During Elimination Phase, Yunnan Province, China, 2011-2013. Emerg Infect Dis 2018; 22:1363-70. [PMID: 27433877 PMCID: PMC4982164 DOI: 10.3201/eid2208.150390] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Malaria was concentrated in a few townships along the China–Myanmar border. To identify township-level high-risk foci of malaria transmission in Yunnan Province, China, along the international border, we retrospectively reviewed data collected in hospitals and clinics of 58 townships in 4 counties during 2011–2013. We analyzed spatiotemporal distribution, especially hot spots of confirmed malaria, using geographic information systems and Getis-Ord Gi*(d) cluster analysis. Malaria incidence, transmission seasonality, and Plasmodium vivax:P. falciparum ratio remained almost unchanged from 2011 to 2013, but heterogeneity in distribution increased. The number of townships with confirmed malaria decreased significantly during the 3 years; incidence became increasingly concentrated within a few townships. High-/low-incidence clusters of P. falciparum shifted in location and size every year, whereas the locations of high-incidence P. vivax townships remained unchanged. All high-incidence clusters were located along the China–Myanmar border. Because of increasing heterogeneity in malaria distribution, microgeographic analysis of malaria transmission hot spots provided useful information for designing targeted malaria intervention during the elimination phase.
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17
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Zaw MT, Thant M, Hlaing TM, Aung NZ, Thu M, Phumchuea K, Phusri K, Saeseu T, Yorsaeng R, Nguitragool W, Felger I, Kaewkungwal J, Cui L, Sattabongkot J. Asymptomatic and sub-microscopic malaria infection in Kayah State, eastern Myanmar. Malar J 2017; 16:138. [PMID: 28376883 PMCID: PMC5381021 DOI: 10.1186/s12936-017-1789-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background Myanmar has the heaviest burden of
malaria in the Greater Mekong Sub-region. Asymptomatic Plasmodium spp. infections are common in this region and may represent an important reservoir of transmission that must be targeted for malaria elimination. Methods A mass blood survey was conducted among 485 individuals from six villages in Kayah State, an area of endemic but low transmission malaria in eastern Myanmar. Malaria infection was screened by rapid diagnostic test (RDT), light microscopy and real-time polymerase chain reaction (PCR), and its association with demographic factors was explored. Results The prevalence of asymptomatic Plasmodium spp. infection was 2.3% (11/485) by real-time PCR. Plasmodium vivax accounted for 72.7% (8/11) and Plasmodium falciparum for 27.3% (3/11) of infections. Men were at greater risk of infection by Plasmodium spp. than women. Individuals who worked as farmers or wood and bamboo cutters had an increased risk of infection. Conclusion A combination of RDT, light microscopy and PCR diagnostics were used to identify asymptomatic malaria infection, providing additional information on asymptomatic cases in addition to the routine statistics on symptomatic cases, so as to determine the true burden of disease in the area. Such information and risk factors can improve malaria risk stratification and guide decision-makers towards better design and delivery of targeted interventions in small villages, representative of Kayah State.
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Affiliation(s)
- Myo Thiha Zaw
- Defence Services Medical Research Centre (DSMRC), Nay Pyi Taw, Myanmar.,Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Myo Thant
- Defence Services Medical Research Centre (DSMRC), Nay Pyi Taw, Myanmar
| | - Tin Maung Hlaing
- Defence Services Medical Research Centre (DSMRC), Nay Pyi Taw, Myanmar
| | - Naing Zin Aung
- Defence Services Medical Research Centre (DSMRC), Nay Pyi Taw, Myanmar.,Loikaw Military Hospital, Loikaw, Kayah, Myanmar
| | - Min Thu
- Loikaw Military Hospital, Loikaw, Kayah, Myanmar
| | - Kanit Phumchuea
- Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanokwan Phusri
- Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Teerawat Saeseu
- Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ritthideach Yorsaeng
- Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ingrid Felger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland
| | - Jaranit Kaewkungwal
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, PA, 16801, USA.
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit (MVRU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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18
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Howes RE, Battle KE, Mendis KN, Smith DL, Cibulskis RE, Baird JK, Hay SI. Global Epidemiology of Plasmodium vivax. Am J Trop Med Hyg 2016; 95:15-34. [PMID: 27402513 PMCID: PMC5198891 DOI: 10.4269/ajtmh.16-0141] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/19/2016] [Indexed: 01/09/2023] Open
Abstract
Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded.
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Affiliation(s)
- Rosalind E. Howes
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Katherine E. Battle
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kamini N. Mendis
- Global Malaria Program, World Health Organization, Geneva, Switzerland
| | - David L. Smith
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - J. Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon I. Hay
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
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19
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Zhu X, Zhao P, Wang S, Liu F, Liu J, Wang J, Yang Z, Yan G, Fan Q, Cao Y, Cui L. Analysis of Pvama1 genes from China-Myanmar border reveals little regional genetic differentiation of Plasmodium vivax populations. Parasit Vectors 2016; 9:614. [PMID: 27899135 PMCID: PMC5129220 DOI: 10.1186/s13071-016-1899-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 11/21/2016] [Indexed: 12/22/2022] Open
Abstract
Background With the premise of diminishing parasite genetic diversity following the reduction of malaria incidence, the analysis of polymorphic antigenic markers may provide important information about the impact of malaria control on local parasite populations. Here we evaluated the genetic diversity of Plasmodium vivax apical membrane antigen 1 (Pvama1) gene in a parasite population from the China-Myanmar border and compared it with global P. vivax populations. Methods We performed evolutionary analysis to examine the genetic diversity, natural selection, and population differentiation of 73 Pvama1 sequences acquired from the China-Myanmar border as well as 615 publically available Pvama1 sequences from seven global P. vivax populations. Results A total of 308 Pvama1 haplotypes were identified among the global P. vivax isolates. The overall nucleotide diversity of Pvama1 gene among the 73 China-Myanmar border parasite isolates was 0.008 with 41 haplotypes being identified (Hd = 0.958). Domain I (DI) harbored the majority (26/33) of the polymorphic sites. The McDonald Kreitman test showed a significant positive selection across the ectodomain and the DI of Pvama1. The fixation index (FST) estimation between the China-Myanmar border, Thailand (0.01) and Myanmar (0.10) showed only slight geographical genetic differentiation. Notably, the Sal-I haplotype was not detected in any of the analyzed global isolates, whereas the Belem strain was restricted to the Thai population. The detected mutations are mapped outside the overlapped region of the predicted B-cell epitopes and intrinsically unstructured/disordered regions. Conclusions This study revealed high levels of genetic diversity of Pvama1 in the P. vivax parasite population from the China-Myanmar border with DI displaying stronger diversifying selection than other domains. There were low levels of population subdivision among parasite populations from the Greater Mekong Subregion. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1899-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Pan Zhao
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Si Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Jun Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Jian Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China. .,Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA.
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20
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Li P, Zhao Z, Xing H, Li W, Zhu X, Cao Y, Yang Z, Sattabongkot J, Yan G, Fan Q, Cui L. Plasmodium malariae and Plasmodium ovale infections in the China-Myanmar border area. Malar J 2016; 15:557. [PMID: 27846879 PMCID: PMC5111346 DOI: 10.1186/s12936-016-1605-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/07/2016] [Indexed: 01/28/2023] Open
Abstract
Background The Greater Mekong Subregion is aiming to achieve regional malaria elimination by 2030. Though a shift in malaria parasite species predominance by Plasmodium vivax has been recently documented, the transmission of the two minor Plasmodium species, Plasmodium malariae and Plasmodium ovale spp., is poorly characterized in the region. This study aims to determine the prevalence of these minor species in the China–Myanmar border area and their genetic diversity. Methods Epidemiology study was conducted during passive case detection in hospitals and clinics in Myanmar and four counties in China along the China–Myanmar border. Cross-sectional surveys were conducted in villages and camps for internally displaced persons to determine the prevalence of malaria infections. Malaria infections were diagnosed initially by microscopy and later in the laboratory using nested PCR for the SSU rRNA genes. Plasmodium malariae and P. ovale infections were confirmed by sequencing the PCR products. The P. ovale subtypes were determined by sequencing the Pocytb, Pocox1 and Pog3p genes. Parasite populations were evaluated by PCR amplification and sequencing of the MSP-1 genes. Antifolate sensitivity was assessed by sequencing the dhfr-ts and dhps genes from the P. malariae and P. ovale isolates. Results Analysis of 2701 blood samples collected from the China–Myanmar border by nested PCR targeting the parasite SSU rRNA genes identified 561 malaria cases, including 161 Plasmodium falciparum, 327 P. vivax, 66 P. falciparum/P. vivax mixed infections, 4 P. malariae and 3 P. ovale spp. P. vivax and P. falciparum accounted for >60 and ~30% of all malaria cases, respectively. In comparison, the prevalence of P. malariae and P. ovale spp. was very low and only made up ~1% of all PCR-positive cases. Nevertheless, these two species were often misidentified as P. vivax infections or completely missed by microscopy even among symptomatic patients. Phylogenetic analysis of the SSU rRNA, Pocytb, Pocox1 and Pog3p genes confirmed that the three P. ovale spp. isolates belonged to the subtype P. ovale curtisi. Low-level genetic diversity was detected in the MSP-1, dhfr and dhps genes of these minor parasite species, potentially stemming from the low prevalence of these parasites preventing their mixing. Whereas most of the dhfr and dhps positions equivalent to those conferring antifolate resistance in P. falciparum and P. vivax were wild type, a new mutation S113C corresponding to the S108 position in pfdhfr was identified in two P. ovale curtisi isolates. Conclusions The four human malaria parasite species all occurred sympatrically at the China–Myanmar border. While P. vivax has become the predominant species, the two minor parasite species also occurred at very low prevalence but were often misidentified or missed by conventional microscopy. These minor parasite species displayed low levels of polymorphisms in the msp-1, dhfr and dhps genes. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1605-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Hua Xing
- Dalian University of Technology, Dalian, Liaoning, China
| | - Wenli Li
- Dalian University of Technology, Dalian, Liaoning, China
| | - Xiaotong Zhu
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Zhaoqing Yang
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
| | | | - Guiyun Yan
- University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China.
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, USA.
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21
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Deng S, Ruan Y, Bai Y, Hu Y, Deng Z, He Y, Ruan R, Wu Y, Yang Z, Cui L. Genetic diversity of the Pvk12 gene in Plasmodium vivax from the China-Myanmar border area. Malar J 2016; 15:528. [PMID: 27809837 PMCID: PMC5096284 DOI: 10.1186/s12936-016-1592-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/28/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Plasmodium falciparum resistance to artemisinin emerged in the Greater Mekong Sub-region has been associated with mutations in the propeller domain of the kelch gene Pfk13. METHODS Here the polymorphisms in Pvk12 gene, the orthologue of Pfk13 in Plasmodium vivax, were determined by PCR and sequencing in 262 clinical isolates collected in recent years (2012-2015) from the China-Myanmar border area. RESULTS Sequencing of full-length Pvk12 genes from these isolates identified three synonymous mutations (N172N, S360S, S697S) and one non-synonymous mutation M124I, all of which were at very low prevalence (2.0-3.1%). Moreover, these mutations were non-overlapping between the two study sites on both sides of the border. Molecular evolutionary analysis detected signature of purifying selection on Pvk12. CONCLUSIONS There is no direct evidence that Pvk12 is involved in artemisinin resistance in P. vivax, but it remains a potential candidate requiring further investigation. Continuous monitoring of potential drug resistance in this parasite is needed in order to facilitate the regional malaria elimination campaign.
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Affiliation(s)
- Shuang Deng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, 650500, Yunnan Province, China.,Department of Pathology, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Yonghua Ruan
- Department of Pathology, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Yao Bai
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, 650500, Yunnan Province, China.,Department of Pharmacology, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Yue Hu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, 650500, Yunnan Province, China.,Department of Pathology, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Zeshuai Deng
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Yongshu He
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Rui Ruan
- Department of Orthopedics, The First Affiliated Hospital, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Yanrui Wu
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, 650500, Yunnan Province, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, 650500, Yunnan Province, China.
| | - Liwang Cui
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, 650500, Yunnan Province, China.
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22
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Zhou G, Lo E, Zhong D, Wang X, Wang Y, Malla S, Lee MC, Yang Z, Cui L, Yan G. Impact of interventions on malaria in internally displaced persons along the China-Myanmar border: 2011-2014. Malar J 2016; 15:471. [PMID: 27628040 PMCID: PMC5024476 DOI: 10.1186/s12936-016-1512-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 09/02/2016] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Internally displaced persons (IDP) represent vulnerable populations whose public health conditions merit special attention. In the China-Myanmar border area, human movement and resettlements of IDP can influence malaria transmission. Comparison of disease incidence and vector densities between IDP camps and surrounding local villages allows for better understanding of current epidemiology and to evaluate the effectiveness of interventions in the region. METHODS Malaria and vector surveillance was conducted in three IDP camps and three local villages neighbouring the camps along the China-Myanmar border in Myanmar. Clinical malaria cases were collected from seven hospitals/clinics from April 2011 to December 2014. Malaria vector population dynamics were monitored using CDC light traps. The use of malaria preventive measures and information on aid agencies and their activities was obtained through questionnaire surveys. RESULTS Malaria was confirmed in 1832 patients. Of these cases, 85.4 % were Plasmodium vivax and 11.4 % were Plasmodium falciparum malaria. Annual malaria incidence rates were 38.8 and 127.0 cases/1000 person year in IDP camps and local villages, respectively. Older children of 5-14 years had the highest incidence rate in the camps regardless of gender, while male adults had significantly higher incidence rates than females in local villages and females child-bearing age had significantly lower risk to malaria in IDP camps compare to local villages. Seasonal malaria outbreaks were observed both in the IDP camps and in the local villages from May to August 2013. The proportion of P. vivax remained unchanged in local villages but increased by approximately tenfold in IDP camps from 2011 to 2014. Anopheles vector density was tenfold higher in local villages compared to IDP camps (2.0:0.2 females/trap/night). Over 99 % of households in both communities owned bed nets. While long-lasting insecticidal nets accounted for 61 % of nets used in IDPs, nearly all residents of local villages owned regular nets without insecticide-impregnation. There were more active aid agencies in the camps than in local villages. CONCLUSION Malaria in IDP camps was significantly lower than the surrounding villages through effective control management. The observation of P. vivax outbreaks in the study area highlights the need for increased control efforts. Expansion of malaria intervention strategies in IDP camps to local surrounding villages is critical to malaria control in the border area.
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Affiliation(s)
- Guofa Zhou
- University of California, Irvine, CA USA
| | - Eugenia Lo
- University of California, Irvine, CA USA
| | | | - Xiaoming Wang
- University of California, Irvine, CA USA
- Southern Medical University, Guangzhou, China
| | - Ying Wang
- Third Military Medical University, Chongqing, China
| | | | | | | | - Liwang Cui
- Pennsylvania State University, University Park, PA USA
| | - Guiyun Yan
- University of California, Irvine, CA USA
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23
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Seasonal dynamics and microgeographical spatial heterogeneity of malaria along the China-Myanmar border. Acta Trop 2016; 157:12-19. [PMID: 26812008 DOI: 10.1016/j.actatropica.2016.01.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 12/29/2015] [Accepted: 01/21/2016] [Indexed: 02/04/2023]
Abstract
Malaria transmission is heterogeneous in the Greater Mekong Subregion with most of the cases occurring along international borders. Knowledge of transmission hotspots is essential for targeted malaria control and elimination in this region. This study aimed to determine the dynamics of malaria transmission and possible existence of transmission hotspots on a microgeographical scale along the China-Myanmar border. Microscopically confirmed clinical malaria cases were recorded in five border villages through a recently established surveillance system between January 2011 and December 2014. A total of 424 clinical cases with confirmed spatial and temporal information were analyzed, of which 330 (77.8%) were Plasmodium vivax and 88 (20.8%) were Plasmodium falciparum, respectively. The P. vivax and P. falciparum case ratio increased dramatically from 2.2 in 2011 to 4.7 in 2014, demonstrating that P. vivax malaria has become the predominant parasite species. Clinical infections showed a strong bimodal seasonality. There were significant differences in monthly average incidence rates among the study villages with rates in a village in China being 3-8 folds lower than those in nearby villages in Myanmar. Spatial analysis revealed the presence of clinical malaria hotspots in four villages. This information on malaria seasonal dynamics and transmission hotspots should be harnessed for planning targeted control.
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24
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Zhou G, Yewhalaw D, Lo E, Zhong D, Wang X, Degefa T, Zemene E, Lee MC, Kebede E, Tushune K, Yan G. Analysis of asymptomatic and clinical malaria in urban and suburban settings of southwestern Ethiopia in the context of sustaining malaria control and approaching elimination. Malar J 2016; 15:250. [PMID: 27129785 PMCID: PMC4851815 DOI: 10.1186/s12936-016-1298-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/15/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Malaria intervention in Ethiopia has been strengthened significantly in the past decade. The Ethiopian government recently stratified the country based upon annual parasite incidence into malaria free, low, moderate and high transmission strata. Districts with low transmission were targeted for indigenous transmission elimination. Surveillance on malaria disease incidence is needed for planning control and elimination efforts. METHODS Clinical malaria was monitored prospectively in health facilities in Jimma town, Oromia Region, southwestern Ethiopia from July 2014 to June 2015. Seasonal cross-sectional parasite prevalence surveys in local communities were conducted in 2014 and 2015 in eight kebeles. Case report forms were administered to obtain sociodemographic and epidemiological information from patients. RESULTS A total of 1434 suspected malaria cases were examined from the health facilities and 428 confirmed malaria cases were found. Among them, 327 (76.4 %) cases were Plasmodium vivax, 97 (22.7 %) were Plasmodium falciparum, and 4 (0.9 %) were mixed infection of P. vivax and P. falciparum. The annual malaria incidence rate was 1.7 cases per 1000 people at risk. Parasite prevalence in the community was less than 3 %. Household ownership of insecticide-treated nets (ITNs) was 47.3 % (1173/2479) and ITN usage was 37.9 %. All ITNs were long-lasting insecticidal nets, and repellent use was not found in the study area. Being male and traveling were the significant risk factors for P. falciparum malaria. For P. vivax malaria, risk factors included occupation and history of malaria illness during the preceding 30 days. CONCLUSION Epidemiological evidence suggested low clinical malaria incidence and prevalence in Jimma town. More aggressive measures may be needed to further suppress vivax transmission. Strategies should be planned targeting sustained control and elimination.
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Affiliation(s)
- Guofa Zhou
- />Program in Public Health, University of California, Irvine, CA 92617 USA
| | - Delenasaw Yewhalaw
- />Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
- />Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Eugenia Lo
- />Program in Public Health, University of California, Irvine, CA 92617 USA
| | - Daibin Zhong
- />Program in Public Health, University of California, Irvine, CA 92617 USA
| | - Xiaoming Wang
- />Program in Public Health, University of California, Irvine, CA 92617 USA
| | - Teshome Degefa
- />Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Endalew Zemene
- />Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Ming-chieh Lee
- />Program in Public Health, University of California, Irvine, CA 92617 USA
| | - Estifanos Kebede
- />Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Kora Tushune
- />Department of Health Management, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Guiyun Yan
- />Program in Public Health, University of California, Irvine, CA 92617 USA
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25
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Liu H, Feng G, Zeng W, Li X, Bai Y, Deng S, Ruan Y, Morris J, Li S, Yang Z, Cui L. A more appropriate white blood cell count for estimating malaria parasite density in Plasmodium vivax patients in northeastern Myanmar. Acta Trop 2016; 156:152-6. [PMID: 26802490 DOI: 10.1016/j.actatropica.2016.01.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 10/22/2022]
Abstract
The conventional method of estimating parasite densities employ an assumption of 8000 white blood cells (WBCs)/μl. However, due to leucopenia in malaria patients, this number appears to overestimate parasite densities. In this study, we assessed the accuracy of parasite density estimated using this assumed WBC count in eastern Myanmar, where Plasmodium vivax has become increasingly prevalent. From 256 patients with uncomplicated P. vivax malaria, we estimated parasite density and counted WBCs by using an automated blood cell counter. It was found that WBC counts were not significantly different between patients of different gender, axillary temperature, and body mass index levels, whereas they were significantly different between age groups of patients and the time points of measurement. The median parasite densities calculated with the actual WBC counts (1903/μl) and the assumed WBC count of 8000/μl (2570/μl) were significantly different. We demonstrated that using the assumed WBC count of 8000 cells/μl to estimate parasite densities of P. vivax malaria patients in this area would lead to an overestimation. For P. vivax patients aged five years and older, an assumed WBC count of 5500/μl best estimated parasite densities. This study provides more realistic assumed WBC counts for estimating parasite densities in P. vivax patients from low-endemicity areas of Southeast Asia.
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26
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Wang Q, Zhao Z, Zhang X, Li X, Zhu M, Li P, Yang Z, Wang Y, Yan G, Shang H, Cao Y, Fan Q, Cui L. Naturally Acquired Antibody Responses to Plasmodium vivax and Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) C-Terminal 19 kDa Domains in an Area of Unstable Malaria Transmission in Southeast Asia. PLoS One 2016; 11:e0151900. [PMID: 26999435 PMCID: PMC4801383 DOI: 10.1371/journal.pone.0151900] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 02/29/2016] [Indexed: 12/24/2022] Open
Abstract
Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals. In addition, 93 and 67 healthy individuals from the same endemic region or from non-endemic region, respectively, were used as controls. Acute malaria infections were identified by microscopy. Anti-recombinant PfMSP119 and PvMSP119 antibody levels were measured by ELISA. Antibody responses to respective MSP119 were detected in 50.9% and 78.2% patients with acute P. vivax and P. falciparum infections, respectively. There were cross-reacting antibodies in Plasmodium patients against these two recombinant proteins, though we could not exclude the possibility of submicroscopic mixed-species infections. IgG1, IgG3 and IgG4 were the major subclasses. Interestingly, 43.2% of the healthy endemic population also had antibodies against PfMSP119, whereas only 3.9% of this population had antibodies against PvMSP119. Higher antibody levels were correlated with age and parasite density, but not with season, gender or malaria history. Both total IgG and individual IgG subclasses underwent substantial declines during the convalescent period in three months. This study demonstrated that individuals in a hypoendemic area with coexistence of P. vivax and P. falciparum can mount rapid antibody responses against both PfMSP119 and PvMSP119. The significantly higher proportion of responders to PfMSP119 in the healthy endemic population indicates higher prevalence of P. falciparum in the recent past. Specific antibodies against PvMSP119 could serve as a marker of recent exposure to P. vivax in epidemiological studies.
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MESH Headings
- Acute Disease
- Adolescent
- Amino Acid Sequence
- Antibodies, Protozoan/immunology
- Antibody Formation/immunology
- Asia, Southeastern/epidemiology
- Child
- Child, Preschool
- Demography
- Follow-Up Studies
- Humans
- Immunoglobulin G/immunology
- Infant
- Logistic Models
- Malaria, Falciparum/blood
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/transmission
- Malaria, Vivax/blood
- Malaria, Vivax/immunology
- Malaria, Vivax/parasitology
- Malaria, Vivax/transmission
- Merozoite Surface Protein 1/chemistry
- Merozoite Surface Protein 1/immunology
- Molecular Weight
- Plasmodium falciparum/immunology
- Plasmodium vivax/immunology
- Protein Structure, Tertiary
- Recombinant Proteins/immunology
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Affiliation(s)
- Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Xuexing Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Xuelian Li
- Department of Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Min Zhu
- School of Humanities and Social Science, China Medical University, Shenyang, Liaoning, China
| | - Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Ying Wang
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, CA, United States of America
| | - Hong Shang
- Department of Laboratory Medicine, the First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
- * E-mail: (YC); (QF); (LC)
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
- * E-mail: (YC); (QF); (LC)
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA, 16802, United States of America
- * E-mail: (YC); (QF); (LC)
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Zhu X, Zhao Z, Feng Y, Li P, Liu F, Liu J, Yang Z, Yan G, Fan Q, Cao Y, Cui L. Genetic diversity of the Plasmodium falciparum apical membrane antigen I gene in parasite population from the China-Myanmar border area. INFECTION GENETICS AND EVOLUTION 2016; 39:155-162. [PMID: 26825252 DOI: 10.1016/j.meegid.2016.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/20/2016] [Accepted: 01/23/2016] [Indexed: 11/28/2022]
Abstract
To investigate the genetic diversity of the Plasmodium falciparum apical membrane antigen 1 (PfAMA1) gene in Southeast Asia, we determined PfAMA1 sequences from 135 field isolates collected from the China-Myanmar border area and compared them with 956 publically available PfAMA1 sequences from seven global P. falciparum populations. This analysis revealed high genetic diversity of PfAMA1 in global P. falciparum populations with a total of 229 haplotypes identified. The genetic diversity of PfAMA1 gene from the China-Myanmar border is not evenly distributed in the different domains of this gene. Sequence diversity in PfAMA1 from the China-Myanmar border is lower than that observed in Thai, African and Oceanian populations, but higher than that in the South American population. This appeared to correlate well with the levels of endemicity of different malaria-endemic regions, where hyperendemic regions favor genetic cross of the parasite isolates and generation of higher genetic diversity. Neutrality tests show significant departure from neutrality in the entire ectodomain and Domain I of PfAMA1 in the China-Myanmar border parasite population. We found evidence supporting a substantial continent-wise genetic structure among P. falciparum populations, with the highest genetic differentiation detected between the China-Myanmar border and the South American populations. Whereas no alleles were unique to a specific region, there were considerable geographical differences in major alleles and their frequencies, highlighting further necessity to include more PfAMA1 alleles in vaccine designs.
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Affiliation(s)
- Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yonghui Feng
- Department of Laboratory Medicine, The First Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Jun Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China; Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA.
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Effects of a malaria elimination program: a retrospective study of 623 cases from 2008 to 2013 in a Chinese county hospital near the China--Myanmar border. Emerg Microbes Infect 2016; 5:e6. [PMID: 26785944 PMCID: PMC4735059 DOI: 10.1038/emi.2016.6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/18/2015] [Accepted: 10/21/2015] [Indexed: 01/11/2023]
Abstract
The southwestern region of China, along the Myanmar border, has accounted for the highest number of cases of imported malaria since China shifted from a malaria control program to an elimination strategy in 2010. We conducted a retrospective study, in which 623 medical charts were analyzed to provide an epidemiological characterization of malaria cases that were diagnosed and treated at the People's Hospital of Tengchong County (PHTC), located in southwestern China, from 2008 to 2013. Our aim was to understand the characteristics of malaria in this region, which is a high-endemic region with imported cases. The majority of patients were male (91.7%), and the average age was 32.4 years. Most of the patients (86.4%) had visited Myanmar; labor was the purpose of travel for 63.9% of the patients. Plasmodium vivax and Plasmodium falciparum were responsible for 53.8% and 34.9% of the infections, respectively. The number of hospitalized patients rose gradually from 2008 to 2010 and reached its peak in 2010 (191). After 2010, the number of hospitalized cases fell rapidly from 191 (2010) to 45 (2013), and the proportion of patients who lived in the forest and the number infected with P. falciparum also fell. In conclusion, the number of hospitalized patients in the southwestern region of China, Tengchong county, decreased after China implemented a malaria elimination strategy in 2010. However, migrant workers returning from Myanmar remained important contributors to cases of imported malaria. The management of imported malaria should be targeted by the malaria elimination program in China.
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Wang Y, Zhong D, Cui L, Lee MC, Yang Z, Yan G, Zhou G. Population dynamics and community structure of Anopheles mosquitoes along the China-Myanmar border. Parasit Vectors 2015; 8:445. [PMID: 26338527 PMCID: PMC4559305 DOI: 10.1186/s13071-015-1057-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 08/26/2015] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Understanding the ecology of malaria vectors such as species composition and population dynamics is essential for developing cost-effective strategies to control mosquito vector populations. METHODS Adult mosquitoes (n = 79,567) were collected in five villages along the China-Myanmar border from April 2012 to September 2014 using the CDC light trap without bait method. Mosquito community structure, Anopheles species composition and diversity were analyzed. RESULTS Twenty species of Anopheles mosquitoes were identified, with An. minimus s.l. accounting for 85% of the total collections. Mosquito densities varied from 0.05 females per trap per night (f/t/n) to 3.00 f/t/n, with strong seasonality in all sites and densities peaked from June to August. An. minimus s.l. was predominant (accounting for 54-91% of total captures) in four villages, An. maculatus s.l. was predominant (71%) in the high elevation village of Dao Nong, and An. culicifacies accounted for 15% of total captures in the peri-urban area of Simsa Lawk. All 20 species have been captured in the Mung Seng Yang village, 18 and 15 species in Ja Htu Kawng and Na Bang respectively, and nine species in both Simsa Lawk and Dao Nong. Species richness peaked from April to August. Species diversity, species dominance index, and species evenness fluctuated substantially from time to time with no clear seasonality, and varied greatly amongst villages. CONCLUSIONS Mosquitoes were abundant in the China-Myanmar bordering agricultural area with clear seasonality. Species composition and density were strongly affected by natural environments. The targeted intervention strategy should be developed and implemented so as to achieve cost-effectiveness for malaria control and elimination along the border areas.
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Affiliation(s)
- Ying Wang
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China.
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA, USA.
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, USA.
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA, USA.
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China.
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA, USA.
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA, USA.
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Wang Y, Yang Z, Yuan L, Zhou G, Parker D, Lee MC, Yan G, Fan Q, Xiao Y, Cao Y, Cui L. Clinical Efficacy of Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria at the China-Myanmar Border. Am J Trop Med Hyg 2015; 93:577-83. [PMID: 26283743 DOI: 10.4269/ajtmh.15-0029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/28/2015] [Indexed: 11/07/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) are currently used as the first-line therapy for uncomplicated Plasmodium falciparum malaria. However, the recent emergence and/or spread of artemisinin resistance in parts of Greater Mekong Subregion (GMS) of southeast Asia requires close monitoring of the therapeutic efficacy of ACTs. This study was conducted from March 2012 to December 2013 in four clinics and seven villages along the China-Myanmar border. A total of 109 patients with uncomplicated falciparum malaria were treated with dihydroartemisinin-piperaquine (DP) and followed up on days 1, 2, 3, 7, 14, 21, 28, and 42 after treatment. A total of 71 patients (22 children and 49 adults) completed the 42-day follow-up. DP remained highly efficacious for treatment of uncomplicated falciparum malaria with an overall 42-day cure rate of 100%. The day 3 parasite-positive rate was 7.04% (5/71). Within 14 days of treatment, a total of 13 (18.31%) patients had detectable gametocytes and a large proportion of these were persistent from the first three days of treatment. The presence of gametocytes in patients through 14 days after DP treatment suggests that the incorporation of a single dose of primaquine for clearing gametocytemia should be considered for blocking parasite transmission.
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Affiliation(s)
- Ying Wang
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Zhaoqing Yang
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Lili Yuan
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Guofa Zhou
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Daniel Parker
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Ming-Chieh Lee
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Guiyun Yan
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Qi Fan
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Yuping Xiao
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Yaming Cao
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
| | - Liwang Cui
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China; Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Program in Public Health, University of California at Irvine, Irvine, California; Dalian Institute of Biotechnology, Dalian, Liaoning, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China; Department of Entomology, Pennsylvania State University, University Park, Pennsylvania
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Li Q, Yang F, Liu R, Luo L, Yang Y, Zhang L, Liu H, Zhang W, Fan Z, Yang Z, Cui L, He Y. Prevalence and Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency at the China-Myanmar Border. PLoS One 2015; 10:e0134593. [PMID: 26226515 PMCID: PMC4520570 DOI: 10.1371/journal.pone.0134593] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/12/2015] [Indexed: 01/03/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary disease that predisposes red blood cells to oxidative damage. G6PD deficiency is particularly prevalent in historically malaria-endemic areas. Use of primaquine for malaria treatment may result in severe hemolysis in G6PD deficient patients. In this study, we systematically evaluated the prevalence of G6PD deficiency in the Kachin (Jingpo) ethnic group along the China-Myanmar border and determined the underlying G6PD genotypes. We surveyed G6PD deficiency in 1770 adult individuals (671 males and 1099 females) of the Kachin ethnicity using a G6PD fluorescent spot test. The overall prevalence of G6PD deficiency in the study population was 29.6% (523/1770), among which 27.9% and 30.6% were males and females, respectively. From these G6PD deficient samples, 198 unrelated individuals (147 females and 51 males) were selected for genotyping at 11 known G6PD single nucleotide polymorphisms (SNPs) in Southeast Asia (ten in exons and one in intron 11) using a multiplex SNaPshot assay. Mutations with known association to a deficient phenotype were detected in 43.9% (87/198) of cases, intronic and synonymous mutations were detected alone in 34.8% (69/198) cases and no mutation were found in 21.2% (42/198) cases. Five non-synonymous mutations, Mahidol 487G>A, Kaiping 1388G>A, Canton 1376G>T, Chinese 4 392G>T, and Viangchan 871G>A were detected. Of the 87 cases with known deficient mutations, the Mahidol variant was the most common (89.7%; 78/87), followed by the Kaiping (8.0%; 7/87) and the Viangchan (2.2%; 2/87) variants. The Canton and Chinese 4 variants were found in 1.1% of these 87 cases. Among them, two females carried the Mahidol/Viangchan and Mahidol/Kaiping double mutations, respectively. Interestingly, the silent SNPs 1311C>T and IVS11nt93T>C both occurred in the same 95 subjects with frequencies at 56.4% and 23.5% in tested females and males, respectively (P<0.05). It is noteworthy that 24 subjects carrying the Mahidol mutation and two carrying the Kaiping mutation also carried the 1311C>T/IVS11nt93T>C SNPs. Further studies are needed to determine the enzyme levels of the G6PD deficient people and presence of additional G6PD mutations in the study population.
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Affiliation(s)
- Qing Li
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Fang Yang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Rong Liu
- The First Affiliated Hospital, Kunming Medical University, Kunming, Yunnan Province, China
| | - Lan Luo
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Yuling Yang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Lu Zhang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Huaie Liu
- The First Affiliated Hospital, Kunming Medical University, Kunming, Yunnan Province, China
| | - Wen Zhang
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Zhixiang Fan
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (LC); (YH)
| | - Yongshu He
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province, China
- * E-mail: (LC); (YH)
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Liu H, Xu JW, Guo XR, Havumaki J, Lin YX, Yu GC, Zhou DL. Coverage, use and maintenance of bed nets and related influence factors in Kachin Special Region II, northeastern Myanmar. Malar J 2015; 14:212. [PMID: 25990715 PMCID: PMC4457094 DOI: 10.1186/s12936-015-0727-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Myanmar is one of the 31 highest burden malaria countries worldwide. Scaling up the appropriate use of insecticide-treated nets (ITNs) is a national policy for malaria prevention and control. However, the data on use, influencing factors and maintenance of bed nets is still lack among the population in Kachin Special Region II (KR2), Northeastern Myanmar. METHODS The study combined a quantitative household questionnaire survey and qualitative direct observation of households. A Chi-squared test was used to compare the percentages of ownership, coverage, and rates of use of bed nets. Additionally, multivariate logistic regression analysis (MVLRA) was used to analyse factors that influence the use of bed nets. Finally, covariance compared the mean calibrated hole indexes (MCHI) across potential influence variables. RESULTS The bed net to person ratio was 1:1.96 (i.e., more than one net for every two people). The long-lasting insecticidal net (LLIN) to person ratio was 1: 2.52. Also, the percentage of households that owned at least one bed net was 99.7% (666/688). Some 3262 (97.3%) residents slept under bed nets the prior night, 2551 (76.1%) of which slept under ITNs/LLINs the prior night (SUITNPN). The poorest families, those with thatched roofing, those who use agriculture as their main source of family income, household heads who knew that mosquitoes transmit malaria and those who used bed nets to prevent malaria, were significantly more likely to be in the SUITNPN group. However, residents in lowlands, and foothills were significantly less likely to be SUITNPNs. Finally, head of household attitude towards fixing bed nets influenced MCHI (F=8.09, P=0.0046). CONCLUSIONS The coverage and usage rates of bed nets were high, especially among children, and pregnant women. Family wealth index, geographical zones, household roofing, source of family income, household head's knowledge of malaria transmission and of using bed nets as tools for malaria prevention are all independent factors which influence use of ITNs/LLINs in KR2. Maintaining high coverage, and use rate of bed nets should be a priority for the war-torn population of KR2 to ensure equity and human rights.
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Affiliation(s)
- Hui Liu
- Yunnan Institute of Parasitic Diseases; Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Collaborative Innovation Centre for Public Health and Disease Prevention and Control, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Puer, 665000, China.
| | - Jian-wei Xu
- Yunnan Institute of Parasitic Diseases; Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Collaborative Innovation Centre for Public Health and Disease Prevention and Control, Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Puer, 665000, China.
| | - Xiang-rui Guo
- Yangjiang County Centre for Disease Control and Prevention, Yangjiang, 679300, China.
| | - Joshua Havumaki
- Foundation for Innovative New Diagnostics, 1216 Cointrin, Geneva, Switzerland.
| | - Ying-xue Lin
- Yangjiang County Centre for Disease Control and Prevention, Yangjiang, 679300, China.
| | - Guo-cui Yu
- Yangjiang County Centre for Disease Control and Prevention, Yangjiang, 679300, China.
| | - Dai-li Zhou
- Yangjiang County Centre for Disease Control and Prevention, Yangjiang, 679300, China.
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Lo E, Zhou G, Oo W, Lee MC, Baum E, Felgner PL, Yang Z, Cui L, Yan G. Molecular inference of sources and spreading patterns of Plasmodium falciparum malaria parasites in internally displaced persons settlements in Myanmar-China border area. INFECTION GENETICS AND EVOLUTION 2015; 33:189-96. [PMID: 25952567 DOI: 10.1016/j.meegid.2015.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/29/2015] [Accepted: 05/02/2015] [Indexed: 10/23/2022]
Abstract
In Myanmar, civil unrest and establishment of internally displaced persons (IDP) settlement along the Myanmar-China border have impacted malaria transmission. The growing IDP populations raise deep concerns about health impact on local communities. Microsatellite markers were used to examine the source and spreading patterns of Plasmodium falciparum between IDP settlement and surrounding villages in Myanmar along the China border. Genotypic structure of P. falciparum was compared over the past three years from the same area and the demographic history was inferred to determine the source of recent infections. In addition, we examined if border migration is a factor of P. falciparum infections in China by determining gene flow patterns across borders. Compared to local community, the IDP samples showed a reduced and consistently lower genetic diversity over the past three years. A strong signature of genetic bottleneck was detected in the IDP samples. P. falciparum infections from the border regions in China were genetically similar to Myanmar and parasite gene flow was not constrained by geographical distance. Reduced genetic diversity of P. falciparum suggested intense malaria control within the IDP settlement. Human movement was a key factor to the spread of malaria both locally in Myanmar and across the international border.
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Affiliation(s)
- Eugenia Lo
- Program in Public Health, University of California, Irvine, CA, USA
| | - Guofa Zhou
- Program in Public Health, University of California, Irvine, CA, USA
| | - Winny Oo
- Program in Public Health, University of California, Irvine, CA, USA
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, CA, USA
| | - Elisabeth Baum
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA.
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Therapeutic responses of Plasmodium vivax malaria to chloroquine and primaquine treatment in northeastern Myanmar. Antimicrob Agents Chemother 2014; 59:1230-5. [PMID: 25512415 DOI: 10.1128/aac.04270-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chloroquine-primaquine (CQ-PQ) continues to be the frontline therapy for radical cure of Plasmodium vivax malaria. Emergence of CQ-resistant (CQR) P. vivax parasites requires a shift to artemisinin combination therapies (ACTs), which imposes a significant financial, logistical, and safety burden. Monitoring the therapeutic efficacy of CQ is thus important. Here, we evaluated the therapeutic efficacy of CQ-PQ for P. vivax malaria in northeast Myanmar. We recruited 587 patients with P. vivax monoinfection attending local malaria clinics during 2012 to 2013. These patients received three daily doses of CQ at a total dose of 24 mg of base/kg of body weight and an 8-day PQ treatment (0.375 mg/kg/day) commencing at the same time as the first CQ dose. Of the 401 patients who finished the 28-day follow-up, the cumulative incidence of recurrent parasitemia was 5.20% (95% confidence interval [CI], 3.04% to 7.36%). Among 361 (61%) patients finishing a 42-day follow-up, the cumulative incidence of recurrent blood-stage infection reached 7.98% (95% CI, 5.20% to 10.76%). The cumulative risk of gametocyte carriage at days 28 and 42 was 2.21% (95% CI, 0.78% to 3.64%) and 3.93% (95% CI, 1.94% to 5.92%), respectively. Interestingly, for all 15 patients with recurrent gametocytemia, this was associated with concurrent asexual stages. Genotyping of recurrent parasites at the merozoite surface protein 3α gene locus from 12 patients with recurrent parasitemia within 28 days revealed that 10 of these were the same genotype as at day 0, suggesting recrudescence or relapse. Similar studies in 70 patients in the same area in 2007 showed no recurrent parasitemias within 28 days. The sensitivity to chloroquine of P. vivax in northeastern Myanmar may be deteriorating.
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