238 results on '"Duong Socheat"'
Search Results
2. Echinostoma revolutum Infection in Children, Pursat Province, Cambodia
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Woon-Mok Sohn, Jong-Yil Chai, Tai-Soon Yong, Keeseon S. Eom, Cheong-Ha Yoon, Muth Sinuon, Duong Socheat, and Soon-Hyung Lee
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Parasites ,Echinostoma revolutum ,echinostomiasis ,trematode ,prevalence ,children ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
To determine the prevalence of helminthic infections in Pursat Province, Cambodia, we tested fecal specimens from 471 children, 10–14 years of age, in June 2007. The prevalence of infection with echinostome flukes ranged from 7.5% to 22.4% in 4 schools surveyed. Adult worms were identified as Echinostoma revolutum.
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- 2011
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3. Differing patterns of selection and geospatial genetic diversity within two leading Plasmodium vivax candidate vaccine antigens.
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Christian M Parobek, Jeffrey A Bailey, Nicholas J Hathaway, Duong Socheat, William O Rogers, and Jonathan J Juliano
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
Although Plasmodium vivax is a leading cause of malaria around the world, only a handful of vivax antigens are being studied for vaccine development. Here, we investigated genetic signatures of selection and geospatial genetic diversity of two leading vivax vaccine antigens--Plasmodium vivax merozoite surface protein 1 (pvmsp-1) and Plasmodium vivax circumsporozoite protein (pvcsp). Using scalable next-generation sequencing, we deep-sequenced amplicons of the 42 kDa region of pvmsp-1 (n = 44) and the complete gene of pvcsp (n = 47) from Cambodian isolates. These sequences were then compared with global parasite populations obtained from GenBank. Using a combination of statistical and phylogenetic methods to assess for selection and population structure, we found strong evidence of balancing selection in the 42 kDa region of pvmsp-1, which varied significantly over the length of the gene, consistent with immune-mediated selection. In pvcsp, the highly variable central repeat region also showed patterns consistent with immune selection, which were lacking outside the repeat. The patterns of selection seen in both genes differed from their P. falciparum orthologs. In addition, we found that, similar to merozoite antigens from P. falciparum malaria, genetic diversity of pvmsp-1 sequences showed no geographic clustering, while the non-merozoite antigen, pvcsp, showed strong geographic clustering. These findings suggest that while immune selection may act on both vivax vaccine candidate antigens, the geographic distribution of genetic variability differs greatly between these two genes. The selective forces driving this diversification could lead to antigen escape and vaccine failure. Better understanding the geographic distribution of genetic variability in vaccine candidate antigens will be key to designing and implementing efficacious vaccines.
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- 2014
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4. Optimising strategies for Plasmodium falciparum malaria elimination in Cambodia: primaquine, mass drug administration and artemisinin resistance.
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Richard J Maude, Duong Socheat, Chea Nguon, Preap Saroth, Prak Dara, Guoqiao Li, Jianping Song, Shunmay Yeung, Arjen M Dondorp, Nicholas P Day, Nicholas J White, and Lisa J White
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Medicine ,Science - Abstract
Malaria elimination requires a variety of approaches individually optimized for different transmission settings. A recent field study in an area of low seasonal transmission in South West Cambodia demonstrated dramatic reductions in malaria parasite prevalence following both mass drug administration (MDA) and high treatment coverage of symptomatic patients with artemisinin-piperaquine plus primaquine. This study employed multiple combined strategies and it was unclear what contribution each made to the reductions in malaria.A mathematical model fitted to the trial results was used to assess the effects of the various components of these interventions, design optimal elimination strategies, and explore their interactions with artemisinin resistance, which has recently been discovered in Western Cambodia. The modelling indicated that most of the initial reduction of P. falciparum malaria resulted from MDA with artemisinin-piperaquine. The subsequent continued decline and near elimination resulted mainly from high coverage with artemisinin-piperaquine treatment. Both these strategies were more effective with the addition of primaquine. MDA with artemisinin combination therapy (ACT) increased the proportion of artemisinin resistant infections, although much less than treatment of symptomatic cases with ACT, and this increase was slowed by adding primaquine. Artemisinin resistance reduced the effectiveness of interventions using ACT when the prevalence of resistance was very high. The main results were robust to assumptions about primaquine action, and immunity.The key messages of these modelling results for policy makers were: high coverage with ACT treatment can produce a long-term reduction in malaria whereas the impact of MDA is generally only short-term; primaquine enhances the effect of ACT in eliminating malaria and reduces the increase in proportion of artemisinin resistant infections; parasite prevalence is a better surveillance measure for elimination programmes than numbers of symptomatic cases; combinations of interventions are most effective and sustained efforts are crucial for successful elimination.
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- 2012
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5. Plasmodium falciparum gametocyte carriage is associated with subsequent Plasmodium vivax relapse after treatment.
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Jessica T Lin, Delia Bethell, Stuart D Tyner, Chanthap Lon, Naman K Shah, David L Saunders, Sabaithip Sriwichai, Phisit Khemawoot, Worachet Kuntawunggin, Bryan L Smith, Harald Noedl, Kurt Schaecher, Duong Socheat, Youry Se, Steven R Meshnick, and Mark M Fukuda
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Medicine ,Science - Abstract
Mixed P. falciparum/P. vivax infections are common in southeast Asia. When patients with P. falciparum malaria are treated and followed for several weeks, a significant proportion will develop P. vivax malaria. In a combined analysis of 243 patients recruited to two malaria treatment trials in western Cambodia, 20/43 (47%) of those with P. falciparum gametocytes on admission developed P. vivax malaria by Day 28 of follow-up. The presence of Pf gametocytes on an initial blood smear was associated with a 3.5-fold greater rate of vivax parasitemia post-treatment (IRR = 3.5, 95% CI 2.0-6.0, p
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- 2011
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6. Pyronaridine-artesunate versus chloroquine in patients with acute Plasmodium vivax malaria: a randomized, double-blind, non-inferiority trial.
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Yi Poravuth, Duong Socheat, Ronnatrai Rueangweerayut, Chirapong Uthaisin, Aung Pyae Phyo, Neena Valecha, B H Krishnamoorthy Rao, Emiliana Tjitra, Asep Purnama, Isabelle Borghini-Fuhrer, Stephan Duparc, Chang-Sik Shin, and Lawrence Fleckenstein
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Medicine ,Science - Abstract
New antimalarials are needed for P. vivax and P. falciparum malaria. This study compared the efficacy and safety of pyronaridine-artesunate with that of chloroquine for the treatment of uncomplicated P. vivax malaria.This phase III randomized, double-blind, non-inferiority trial included five centers across Cambodia, Thailand, India, and Indonesia. In a double-dummy design, patients (aged >3-≤ 60 years) with microscopically confirmed P. vivax mono-infection were randomized (1:1) to receive pyronaridine-artesunate (target dose 7.2:2.4 mg/kg to 13.8:4.6 mg/kg) or chloroquine (standard dose) once daily for three days. Each treatment group included 228 randomized patients. Outcomes for the primary endpoint, Day-14 cure rate in the per-protocol population, were 99.5%, (217/218; 95%CI 97.5, 100) with pyronaridine-artesunate and 100% (209/209; 95%CI 98.3, 100) with chloroquine. Pyronaridine was non-inferior to chloroquine: treatment difference -0.5% (95%CI -2.6, 1.4), i.e., the lower limit of the 2-sided 95%CI for the treatment difference was greater than -10%. Pyronaridine-artesunate cure rates were non-inferior to chloroquine for Days 21, 28, 35 and 42. Parasite clearance time was shorter with pyronaridine-artesunate (median 23.0 h) versus chloroquine (32.0 h; p
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- 2011
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7. Population genetic analysis of Plasmodium falciparum parasites using a customized Illumina GoldenGate genotyping assay.
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Susana Campino, Sarah Auburn, Katja Kivinen, Issaka Zongo, Jean-Bosco Ouedraogo, Valentina Mangano, Abdoulaye Djimde, Ogobara K Doumbo, Steven M Kiara, Alexis Nzila, Steffen Borrmann, Kevin Marsh, Pascal Michon, Ivo Mueller, Peter Siba, Hongying Jiang, Xin-Zhuan Su, Chanaki Amaratunga, Duong Socheat, Rick M Fairhurst, Mallika Imwong, Timothy Anderson, François Nosten, Nicholas J White, Rhian Gwilliam, Panos Deloukas, Bronwyn MacInnis, Christopher I Newbold, Kirk Rockett, Taane G Clark, and Dominic P Kwiatkowski
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Medicine ,Science - Abstract
The diversity in the Plasmodium falciparum genome can be used to explore parasite population dynamics, with practical applications to malaria control. The ability to identify the geographic origin and trace the migratory patterns of parasites with clinically important phenotypes such as drug resistance is particularly relevant. With increasing single-nucleotide polymorphism (SNP) discovery from ongoing Plasmodium genome sequencing projects, a demand for high SNP and sample throughput genotyping platforms for large-scale population genetic studies is required. Low parasitaemias and multiple clone infections present a number of challenges to genotyping P. falciparum. We addressed some of these issues using a custom 384-SNP Illumina GoldenGate assay on P. falciparum DNA from laboratory clones (long-term cultured adapted parasite clones), short-term cultured parasite isolates and clinical (non-cultured isolates) samples from East and West Africa, Southeast Asia and Oceania. Eighty percent of the SNPs (n = 306) produced reliable genotype calls on samples containing as little as 2 ng of total genomic DNA and on whole genome amplified DNA. Analysis of artificial mixtures of laboratory clones demonstrated high genotype calling specificity and moderate sensitivity to call minor frequency alleles. Clear resolution of geographically distinct populations was demonstrated using Principal Components Analysis (PCA), and global patterns of population genetic diversity were consistent with previous reports. These results validate the utility of the platform in performing population genetic studies of P. falciparum.
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- 2011
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8. Artesunate dose escalation for the treatment of uncomplicated malaria in a region of reported artemisinin resistance: a randomized clinical trial.
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Delia Bethell, Youry Se, Chanthap Lon, Stuart Tyner, David Saunders, Sabaithip Sriwichai, Sea Darapiseth, Paktiya Teja-Isavadharm, Phisit Khemawoot, Kurt Schaecher, Wiriya Ruttvisutinunt, Jessica Lin, Worachet Kuntawungin, Panita Gosi, Ans Timmermans, Bryan Smith, Duong Socheat, and Mark M Fukuda
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Medicine ,Science - Abstract
The emergence of artemisinin resistance has raised concerns that the most potent antimalarial drug may be under threat. The currently recommended daily dose of artesunate (AS) is 4 mg/kg, and is administered for 3 days together with a partner antimalarial drug. This study investigated the impact of different AS doses on clinical and parasitological responses in malaria patients from an area of known artemisinin resistance in western Cambodia.Adult patients with uncomplicated P. falciparum malaria were randomized into one of three 7-day AS monotherapy regimens: 2, 4 or 6 mg/kg/day (total dose 14, 28 and 42 mg/kg). Clinical, parasitological, pharmacokinetic and in vitro drug sensitivity data was collected over a 7-day inpatient period and during weekly follow-up to 42 days.143 patients were enrolled (n = 75, 40 and 28 to receive AS 2, 4 and 6 mg/kg/day respectively). Cure rates were high in all treatment groups at 42 days despite almost half the patients remaining parasitemic on Day 3. There was no impact of increasing AS dose on median parasite clearance times, median parasite clearance rates or on the proportion of patients remaining parasitemic on Day 3. However at the lowest dose used (2 mg/kg/d) patients with parasitemia >10,000/µL had longer median (IQR) parasite clearance times than those with parasitemia
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- 2011
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9. Cost of dengue and other febrile illnesses to households in rural Cambodia: a prospective community-based case-control study
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Margolis Harold S, Duong Socheat, Ngan Chantha, Beatty Mark, Wichmann Ole, Huy Rekol, and Vong Sirenda
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Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background The average annual reported dengue incidence in Cambodia is 3.3/1,000 among children < 15 years of age (2002–2007). To estimate the economic burden of dengue, accurate cost-of-illness data are essential. We conducted a prospective, community-based, matched case-control study to assess the cost and impact of an episode of dengue fever and other febrile illness on households in rural Cambodia. Methods In 2006, active fever surveillance was conducted among a cohort of 6,694 children aged ≤ 15 years in 16 villages in Kampong Cham province, Cambodia. Subsequently, a case-control study was performed by individually assigning one non-dengue febrile control from the cohort to each laboratory-confirmed dengue case. Parents of cases and controls were interviewed using a standardized questionnaire to determine household-level, illness-related expenditures for medical and non-medical costs, and estimated income loss (see Additional file 1). The household socio-economic status was determined and its possible association with health seeking behaviour and the ability to pay for the costs of a febrile illness. Additional File 1 2006 cost study survey questionnaire, Cambodia. the questionnaire represents the data collection instrument that was developed and used during the present study. Click here for file Results Between September and November 2006, a total of 60 household heads were interviewed: 30 with dengue-positive and 30 with dengue-negative febrile children. Mean total dengue-related costs did not differ from those of other febrile illnesses (31.5 vs. 27.2 US$, p = 0.44). Hospitalization almost tripled the costs of dengue (from 14.3 to 40.1 US$) and doubled the costs of other febrile illnesses (from 17.0 to 36.2 US$). To finance the cost of a febrile illness, 67% of households incurred an average debt of 23.5 US$ and higher debt was associated with hospitalization compared to outpatient treatment (US$ 23.1 vs. US$ 4.5, p < 0.001). These costs compared to an average one-week expenditure on food of US$ 9.5 per household (range 2.5–21.3). In multivariate analysis, higher socio-economic status (odds ratio [OR] 4.4; 95% confidence interval [CI] 1.4–13.2), duration of fever (OR 2.1; 95%CI 1.3–3.5), and age (OR 0.8; 95%CI 0.7–0.9) were independently associated with hospitalization. Conclusion In Cambodia, dengue and other febrile illnesses pose a financial burden to households. A possible reason for a lower rate of hospitalization among children from poor households could be the burden of higher illness-related costs and debts.
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- 2009
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10. Production and validation of durable, high quality standardized malaria microscopy slides for teaching, testing and quality assurance during an era of declining diagnostic proficiency
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Sismadi Priyanto, Muth Sinuon, Duong Socheat, Jordon Robert G, O'Meara Wendy, Barcus Mazie J, Lederman Edith R, Maguire Jason D, Bangs Michael J, Prescott W Roy, Baird J Kevin, and Wongsrichanalai Chansuda
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Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Sets of Giemsa-stained, blood smear slides with systematically verified composite diagnoses would contribute substantially to development of externally validated quality assurance systems for the microscopic diagnosis of malaria. Methods whole blood from Plasmodium-positive donors in Cambodia and Indonesia and individuals with no history of risk for malaria was collected. Using standard operating procedures, technicians prepared Giemsa-stained thick and thin smears from each donor. One slide from each of the first 35 donations was distributed to each of 28 individuals acknowledged by reputation as having expertise in the microscopic diagnosis of malaria. These reference readers recorded presence or absence of Plasmodium species and parasite density. A composite diagnosis for each donation was determined based on microscopic findings and species-specific small subunit ribosomal RNA (ssrRNA) DNA polymerase chain reaction (PCR) amplification. Results More than 12, 000 slides were generated from 124 donations. Reference readers correctly identified presence of parasites on 85% of slides with densities 350 parasites/μl. Percentages of agreement with composite diagnoses were highest for Plasmodium falciparum (99%), followed by Plasmodium vivax (86%). Conclusion Herein, a standardized method for producing large numbers of consistently high quality, durable Giemsa-stained blood smears and validating composite diagnoses for the purpose of creating a malaria slide repository in support of initiatives to improve training and competency assessment amidst a background of variability in diagnosis is described.
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- 2006
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11. Novel phenotypic assays for the detection of artemisinin-resistant Plasmodium falciparum malaria in Cambodia: in-vitro and ex-vivo drug-response studies
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Witkowski, Benoit, Amaratunga, Chanaki, Khim, Nimol, Sreng, Sokunthea, Chim, Pheaktra, Kim, Saorin, Lim, Pharath, Mao, Sivanna, Sopha, Chantha, Sam, Baramey, Anderson, Jennifer M, Duong, Socheat, Chuor, Char Meng, Taylor, Walter R J, Suon, Seila, Mercereau-Puijalon, Odile, Fairhurst, Rick M, and Menard, Didier
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- 2013
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12. Higher microsatellite diversity in Plasmodium vivax than in sympatric Plasmodium falciparum populations in Pursat, Western Cambodia
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Orjuela-Sánchez, Pamela, Sá, Juliana M., Brandi, Michelle C.C., Rodrigues, Priscila T., Bastos, Melissa S., Amaratunga, Chanaki, Duong, Socheat, Fairhurst, Rick M., and Ferreira, Marcelo U.
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- 2013
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13. Evaluation of real-time PCR for Strongyloides stercoralis and hookworm as diagnostic tool in asymptomatic schoolchildren in Cambodia
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Schär, Fabian, Odermatt, Peter, Khieu, Virak, Panning, Marcus, Duong, Socheat, Muth, Sinuon, Marti, Hanspeter, and Kramme, Stefanie
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- 2013
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14. Artemisinin-resistant Plasmodium falciparum in Pursat province, western Cambodia: a parasite clearance rate study
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Amaratunga, Chanaki, Sreng, Sokunthea, Suon, Seila, Phelps, Erika S, Stepniewska, Kasia, Lim, Pharath, Zhou, Chongjun, Mao, Sivanna, Anderson, Jennifer M, Lindegardh, Niklas, Jiang, Hongying, Song, Jianping, Su, Xin-zhuan, White, Nicholas J, Dondorp, Arjen M, Anderson, Tim JC, Fay, Michael P, Mu, Jianbing, Duong, Socheat, and Fairhurst, Rick M
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- 2012
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15. Residual Antimalarial Concentrations before Treatment in Patients with Malaria from Cambodia: Indication of Drug Pressure
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Hodel, Eva Maria, Genton, Blaise, Zanolari, Boris, Mercier, Thomas, Duong, Socheat, Beck, Hans-Peter, Olliaro, Piero, Decosterd, Laurent Arthur, and Ariey, Frédéric
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- 2010
16. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria
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Aney, Frederic, Witkowski, Benoit, Amaratunga, Chanaki, Beghain, Johann, Langlois, Anne-Claire, Khim, Nimol, Kim, Saorin, Duru, Valentine, Bouchier, Christiane, Ma, Laurence, Lim, Pharath, Leang, Rithea, Duong, Socheat, Sreng, Sokunthea, Suon, Seila, Chuor, Char Meng, Bout, Denis Mey, Menard, Sandie, Rogers, William O., Genton, Blaise, Fandeur, Thierry, Miotto, Olivo, Ringwald, Pascal, Bras, Jacques Le, Berry, Antoine, Barale, Jean-Christophe, Fairhurst, Rick M., Benoit-Vical, Francoise, Mercereau-Puijalon, Odile, and Menard, Didier
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Drug resistance in microorganisms -- Research ,Molecular biology -- Research ,Plasmodium falciparum -- Physiological aspects -- Health aspects ,Microbiological research ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain ('K13-propeller') with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread., The emergence of Plasmodium falciparum resistance to artemisinin derivatives (ART) in Cambodia threatens the world's malaria control and elimination efforts (1,2). The risk of ART-resistant parasites spreading from western Cambodia [...]
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- 2014
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17. Molecular surveillance for multidrug-resistant Plasmodium falciparum, Cambodia
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Shah, Naman K., Alker, Alisa P., Sem, Rithy, Susanti, Agustina Ika, Muth, Sinuon, Maguire, Jason D., Duong, Socheat, Ariey, Frederic, Meshnick, Steven R., and Wongsrichanalai, Chansuda
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Mefloquine -- Dosage and administration ,Mefloquine -- Research ,Plasmodium falciparum -- Health aspects ,Plasmodium falciparum -- Genetic aspects ,Plasmodium falciparum -- Research ,Malaria -- Risk factors ,Malaria -- Diagnosis ,Malaria -- Research ,Genes -- Research - Abstract
We conducted surveillance for multidrug-resistant P/asmodium falciparum in Cambodia during 2004-2006 by assessing molecular changes in pfmdr1. The high prevalence of isolates with multiple pfmdr1 copies found in western Cambodia [...]
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- 2008
18. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria
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Ariey, Frédéric, Witkowski, Benoit, Amaratunga, Chanaki, Beghain, Johann, Langlois, Anne-Claire, Khim, Nimol, Kim, Saorin, Duru, Valentine, Bouchier, Christiane, Ma, Laurence, Lim, Pharath, Leang, Rithea, Duong, Socheat, Sreng, Sokunthea, Suon, Seila, Chuor, Char Meng, Bout, Denis Mey, Ménard, Sandie, Rogers, William O., Genton, Blaise, Fandeur, Thierry, Miotto, Olivo, Ringwald, Pascal, Le Bras, Jacques, Berry, Antoine, Barale, Jean-Christophe, Fairhurst, Rick M., Benoit-Vical, Françoise, Mercereau-Puijalon, Odile, and Ménard, Didier
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- 2014
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19. Schistosoma mekongi in Cambodia and Lao People's Democratic Republic
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Muth, Sinuon, primary, Sayasone, Somphou, additional, Odermatt-Biays, Sophie, additional, Phompida, Samlane, additional, Duong, Socheat, additional, and Odermatt, Peter, additional
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- 2010
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20. Elimination of Lymphatic Filariasis in Southeast Asia
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Sudomo, Mohammad, primary, Chayabejara, Sombat, additional, Duong, Socheat, additional, Hernandez, Leda, additional, Wu, Wei-Ping, additional, and Bergquist, Robert, additional
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- 2010
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21. Increasing Access to Early Malaria Diagnosis and Prompted Treatment in Remote Cambodian Villages
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Kheang, Soy Ty, Duong, Socheat, and Olkkonen, Aida
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- 2011
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22. Plasmodium knowlesi infection in humans, Cambodia, 2007-2010
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Khim, Nimol, Siv, Sovannaroth, Kim, Saorin, Mueller, Tara, Fleischmann, Erna, Singh, Balbir, Divis, Paul Cliff Simon, Steenkeste, Nicolas, Duval, Linda, Bouchier, Christiane, Duong, Socheat, Ariey, Frederic, and Menard, Didier
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Malaria -- Risk factors -- Diagnosis -- Care and treatment -- Research ,Plasmodium falciparum -- Health aspects -- Research ,Polymerase chain reaction -- Usage ,Health - Abstract
In Cambodia, malaria ranks among the leading causes of illness and death. Mostly affecting the ≅ 3 million persons (23% of Cambodia's population) who live near forested areas, malaria remains [...]
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- 2011
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23. Pfcrt genotypes and related microsatellite DNA polymorphisms on Plasmodium falciparum differed among populations in the Greater Mekong Subregion
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Paul T. Brey, Masamine Jimba, Polrat Wilairatana, Noppadon Tangpukdee, Hisami Watanabe, Bouasy Hongvanthong, Duong Socheat, Jun Kobayashi, Junko Yasuoka, Shigeyuki Kano, Moritoshi Iwagami, Le Duc Dao, Hiromu Toma, Shusuke Nakazawa, Muth Sinuon, Viengxay Vanisaveth, and Srivicha Krudsood
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Genotype ,030231 tropical medicine ,Population ,Plasmodium falciparum ,Drug Resistance ,Protozoan Proteins ,Drug resistance ,Biology ,03 medical and health sciences ,Antimalarials ,0302 clinical medicine ,Chloroquine ,parasitic diseases ,medicine ,030212 general & internal medicine ,education ,Asia, Southeastern ,Genetics ,education.field_of_study ,Genetic diversity ,Polymorphism, Genetic ,Membrane Transport Proteins ,DNA, Protozoan ,biology.organism_classification ,medicine.disease ,Infectious Diseases ,Mutation ,Microsatellite ,Parasitology ,Malaria ,medicine.drug ,Microsatellite Repeats - Abstract
Malaria morbidity and mortality have decreased gradually in the Greater Mekong Subregion (GMS). Presently, WHO sets a goal to eliminate malaria by 2030 in the GMS. However, drug-resistant malaria has been reported from several endemic areas. To achieve the goal of elimination, the status of the emergence and spread of drug resistance should be monitored. In this study, the genotype of the Plasmodium falciparum chloroquine (CQ) resistance transporter gene (pfcrt) and 6 microsatellite DNA loci flanking the gene were examined. P. falciparum isolates (n = 136) was collected from malaria patients in Thailand (n = 50, 2002–2005), Vietnam (n = 39, 2004), Laos (n = 15, 2007) and Cambodia (n = 32, 2009). Amino acid sequences at codons 72–76 on the gene were determined. All of the isolates from Thailand were CQ-resistant (CVIET), as were all of the isolates from Cambodia (CVIET, CVIDT). Thirteen of the 15 isolates (87%) from Laos were CQ-resistant (CVIET, CVIDT), whereas the other 2 (13%) were CQ-susceptible (CVMNK). In contrast, 27 of the 39 isolates (69%) from Vietnam were CQ-susceptible (CVMNK), whereas the other 12 (31%) were CQ-resistant (CVIET, CVIDT, CVMDT) or mixed (CVMNK/CVIDT). The mean of expected heterozygosity of the microsatellite loci was 0.444 in the Thai population, 0.482 in the Cambodian population, and 0.734 in the Vietnamese population. Genetic diversity in the Thai population was significantly lower than that in the Vietnamese population. These results suggested that chloroquine selective pressure on P. falciparum populations is heterogeneous in the GMS. Therefore, further examination to understand the mechanisms behind the emergence and spread of drug-resistant malaria are needed.
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- 2017
24. Prevalence of Intestinal Helminths among Inhabitants of Cambodia (2006-2011)
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Hoo Gn Jeoung, Woon Mok Sohn, Duong Socheat, Keeseon S. Eom, Jong-Yil Chai, Eui Hyug Hoang, Bong Kwang Jung, Muth Sinuon, Tai Soon Yong, Soon Hyung Lee, and Cheong Ha Yoon
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Adult ,Male ,Hookworm ,Veterinary medicine ,Adolescent ,prevalence ,Helminthiasis ,Prevalence ,Feces ,Young Adult ,Helminths ,parasitic diseases ,medicine ,Animals ,Humans ,Opisthorchis viverrini ,Enterobius ,Intestinal Diseases, Parasitic ,Child ,Aged ,Aged, 80 and over ,biology ,Middle Aged ,biology.organism_classification ,medicine.disease ,intestinal helminth ,Infectious Diseases ,Trichuris trichiura ,Taenia ,Original Article ,Female ,Topography, Medical ,Parasitology ,Ascaris lumbricoides ,Cambodia - Abstract
In order to investigate the status of intestinal helminthic infections in Cambodia, epidemiological surveys were carried out on a national scale, including 19 provinces. A total of 32,201 fecal samples were collected from schoolchildren and adults between 2006 and 2011 and examined once by the Kato-Katz thick smear technique. The overall egg positive rate of intestinal helminths was 26.2%. The prevalence of hookworms was the highest (9.6%), followed by that of Opisthorchis viverrini/minute intestinal flukes (Ov/MIF) (5.7%), Ascaris lumbricoides (4.6%), and Trichuris trichiura (4.1%). Other types of parasites detected were Enterobius vermicularis (1.1%), Taenia spp. (0.4%), and Hymenolepis spp. (0.2%). The northwestern regions such as the Siem Reap, Oddar Meanchey, and Banteay Meanchey Provinces showed higher prevalences (17.4-22.3%) of hookworms than the other localities. The southwestern areas, including Koh Kong and Preah Sihanouk Provinces showed higher prevalences of A. lumbricoides (17.5-19.2%) and T. trichiura (6.1-21.0%). Meanwhile, the central and southern areas, in particular, Takeo and Kampong Cham Provinces, showed high prevalences of Ov/MIF (23.8-24.0%). The results indicate that a considerably high prevalence of intestinal helminths has been revealed in Cambodia, and thus sustained national parasite control projects are necessary to reduce morbidity due to parasitic infections in Cambodia.
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- 2014
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25. Laboratory Detection of Artemisinin-Resistant Plasmodium falciparum
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Duong Socheat, Rupam Tripura, Debashish Das, Nicholas J. White, Char Meng Chuor, Nicholas P. J. Day, Arjen M. Dondorp, Kesinee Chotivanich, Sasithon Pukrittayakamee, and Poravuth Yi
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Plasmodium falciparum ,030231 tropical medicine ,Drug Resistance ,Artesunate ,Antimalarials ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Parasitic Sensitivity Tests ,In vivo ,parasitic diseases ,Animals ,Medicine ,Parasite hosting ,Pharmacology (medical) ,Malaria, Falciparum ,Artemisinin ,IC50 ,Pharmacology ,0303 health sciences ,biology ,030306 microbiology ,business.industry ,biology.organism_classification ,Molecular biology ,Artemisinins ,In vitro ,3. Good health ,Phenotype ,Infectious Diseases ,chemistry ,Susceptibility ,Immunology ,business ,Clearance rate ,Half-Life ,medicine.drug - Abstract
Conventional 48-h in vitro susceptibility tests have low sensitivity in identifying artemisinin-resistant Plasmodium falciparum , defined phenotypically by low in vivo parasite clearance rates. We hypothesized originally that this discrepancy was explained by a loss of ring-stage susceptibility and so developed a simple field-adapted 24-h trophozoite maturation inhibition (TMI) assay focusing on the ring stage and compared it to the standard 48-h schizont maturation inhibition (WHO) test. In Pailin, western Cambodia, where artemisinin-resistant P. falciparum is prevalent, the TMI test mean (95% confidence interval) 50% inhibitory concentration (IC 50 ) for artesunate was 6.8 (5.2 to 8.3) ng/ml compared with 1.5 (1.2 to 1.8) ng/ml for the standard 48-h WHO test ( P = 0.001). TMI IC 50 s correlated significantly with the in vivo responses to artesunate (parasite clearance time [ r = 0.44, P = 0.001] and parasite clearance half-life [ r = 0.46, P = 0.001]), whereas the standard 48-h test values did not. On continuous culture of two resistant isolates, the artemisinin-resistant phenotype was lost after 6 weeks (IC 50 s fell from 10 and 12 ng/ml to 2.7 and 3 ng/ml, respectively). Slow parasite clearance in falciparum malaria in western Cambodia results from reduced ring-stage susceptibility.
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- 2014
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26. Zoonotic Trematode Metacercariae in Fish from Phnom Penh and Pursat, Cambodia
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Duong Socheat, Keeseon S. Eom, Woon Mok Sohn, Hoo Gn Jeoung, Eui Hyug Hoang, Byoung Kuk Na, Cheong Ha Yoon, Jong-Yil Chai, and Tai Soon Yong
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Pristolepis fasciata ,Zoology ,Centrocestus formosanus ,Anabas testudineus ,Trematode Infections ,Fish Diseases ,Prevalence ,Animals ,Humans ,Metacercariae ,Opisthorchis viverrini ,Haplorchis yokogawai ,Procerovum sp ,biology ,Intermediate host ,zoonotic trematode ,biology.organism_classification ,Fishery ,Infectious Diseases ,Haplorchis pumilio ,Henicorhynchus lineatus ,Freshwater fish ,Original Article ,Parasitology ,Trematoda ,Cambodia - Abstract
A survey was performed to investigate the infection status of freshwater fish with zoonotic trematode metacercariae in Phnom Penh and Pursat Province, Cambodia. All collected fish with ice were transferred to our laboratory and examined using the artificial digestion method. In fish from Phnom Penh, 2 kinds of metacercariae (Opisthorchis viverrini and Haplorchis yokogawai) were detected. O. viverrini metacercariae were positive in 37 (50.0%) of 74 fish in 11 species (average no. metacercariae/fish, 18.6). H. yokogawai metacercariae were detected in 23 (57.5%) of 40 fish in 5 species (average no. metacercariae/fish, 21.0). In fish from Pursat Province, 5 kinds of metacercariae (O. viverrini, H. yokogawai, Haplorchis pumilio, Centrocestus formosanus, and Procerovum sp.) were detected; O. viverrini metacercariae (n=3) in 2 fish species (Henicorhynchus lineatus and Puntioplites falcifer), H. yokogawai metacercariae (n=51) in 1 species (P. falcifer), H. pumilio metacercariae (n=476) in 2 species (H. lineatus and Pristolepis fasciata), C. formosanus metacercariae (n=1) in 1 species (H. lineatus), and Procerovum sp. metacercariae (n=63) in 1 species (Anabas testudineus). From the above results, it has been confirmed that various freshwater fish play the role of a second intermediate host for zoonotic trematodes (O. viverrini, H. yokogawai, H. pumilio, C. formosanus, and Procerovum sp.) in Cambodia.
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- 2014
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27. Intrahost modeling of artemisinin resistance in Plasmodium falciparum
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Lisa J. White, François Nosten, Nicholas J. White, Duong Socheat, Wirichada Pan-Ngum, Arjen M. Dondorp, Sue J. Lee, Kesinee Chotivanich, Richard J. Maude, Sompob Saralamba, Joel Tarning, Nicholas P. J. Day, and Niklas Lindegardh
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Plasmodium falciparum ,Drug Resistance ,Artesunate ,Drug resistance ,Biology ,Models, Biological ,Host-Parasite Interactions ,Antimalarials ,03 medical and health sciences ,chemistry.chemical_compound ,In vivo ,parasitic diseases ,medicine ,Animals ,Humans ,Parasite hosting ,Malaria, Falciparum ,Artemisinin ,030304 developmental biology ,0303 health sciences ,Multidisciplinary ,Dose-Response Relationship, Drug ,030306 microbiology ,Artemisinin resistance ,Biological Sciences ,medicine.disease ,biology.organism_classification ,Artemisinins ,3. Good health ,chemistry ,Immunology ,Linear Models ,Cambodia ,Malaria ,medicine.drug - Abstract
Artemisinin-resistant Plasmodium falciparum malaria has emerged in western Cambodia. Resistance is characterized by prolonged in vivo parasite clearance times (PCTs) following artesunate treatment. The biological basis is unclear. The hypothesis that delayed parasite clearance results from a stage-specific reduction in artemisinin sensitivity of the circulating young asexual parasite ring stages was examined. A mathematical model was developed, describing the intrahost parasite stage-specific pharmacokinetic–pharmacodynamic relationships. Model parameters were estimated using detailed pharmacokinetic and parasite clearance data from 39 patients with uncomplicated falciparum malaria treated with artesunate from Pailin (western Cambodia) where artemisinin resistance was evident and 40 patients from Wang Pha (northwestern Thailand) where efficacy was preserved. The mathematical model reproduced the observed parasite clearance for each patient with an accurate goodness of fit (rmsd: 0.03–0.67 in log 10 scale). The parameter sets that provided the best fits with the observed in vivo data consist of a highly conserved concentration–effect relationship for the trophozoite and schizont parasite stages, but a variable relationship for the ring stages. The model-derived assessment suggests that the efficacy of artesunate on ring stage parasites is reduced significantly in Pailin. This result supports the hypothesis that artemisinin resistance mainly reflects reduced ring-stage susceptibility and predicts that doubling the frequency of dosing will accelerate clearance of artemisinin-resistant parasites.
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- 2016
28. Effect of high-dose or split-dose artesunate on parasite clearance in artemisinin-resistant falciparum malaria
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Poravuth Yi, Sue J. Lee, Khin Maung Lwin, Didier Menard, Kesinee Chotivanich, Duong Socheat, Pascal Ringwald, Nicholas P. J. Day, Debashish Das, Joel Tarning, François Nosten, Kasia Stepniewska, Niklas Lindegardh, Mallika Imwong, Warunee Hanpithakpong, Nicholas J. White, Kamolrat Silamut, Chea Nguon, Aung Pyae Phyo, Arjen M. Dondorp, and Rupam Tripura
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Male ,medicine.medical_treatment ,Administration, Oral ,Antibodies, Protozoan ,Artesunate ,Pharmacology ,Parasitemia ,Parasite Load ,chemistry.chemical_compound ,0302 clinical medicine ,Medicine ,Artemisinin ,Malaria, Falciparum ,Child ,Articles and Commentaries ,0303 health sciences ,education.field_of_study ,biology ,Mefloquine ,Thailand ,Artemisinins ,3. Good health ,Infectious Diseases ,Treatment Outcome ,Female ,Cambodia ,medicine.drug ,Half-Life ,Microbiology (medical) ,Adult ,Combination therapy ,Adolescent ,030231 tropical medicine ,Population ,Plasmodium falciparum ,Dihydroartemisinin ,Electronic Articles ,03 medical and health sciences ,Young Adult ,Antimalarials ,reticulocytopenia ,parasitic diseases ,neutropenia ,Humans ,education ,drug resistance ,030306 microbiology ,business.industry ,medicine.disease ,biology.organism_classification ,Virology ,chemistry ,Immunoglobulin G ,business ,Malaria - Abstract
New treatment strategies are needed for artemisinin-resistant falciparum malaria. This randomized trial shows that neither increasing nor splitting the standard once-daily artesunate dose reverses the markedly reduced parasite clearance rate in patients with artemisinin-resistant falciparum malaria., Background. The emergence of Plasmodium falciparum resistance to artemisinins on the Cambodian and Myanmar-Thai borders poses severe threats to malaria control. We investigated whether increasing or splitting the dose of the short-half-life drug artesunate improves parasite clearance in falciparum malaria in the 2 regions. Methods. In Pailin, western Cambodia (from 2008 to 2010), and Wang Pha, northwestern Thailand (2009–2010), patients with uncomplicated falciparum malaria were randomized to oral artesunate 6 mg/kg/d as a once-daily or twice-daily dose for 7 days, or artesunate 8 mg/kg/d as a once-daily or twice-daily dose for 3 days, followed by mefloquine. Parasite clearance and recrudescence for up to 63 days of follow-up were assessed. Results. A total of 159 patients were enrolled. Overall median (interquartile range [IQR]) parasitemia half-life (half-life) was 6.03 (4.89–7.28) hours in Pailin versus 3.42 (2.20–4.85) hours in Wang Pha (P = .0001). Splitting or increasing the artesunate dose did not shorten half-life in either site. Pharmacokinetic profiles of artesunate and dihydroartemisinin were similar between sites and did not correlate with half-life. Recrudescent infections occurred in 4 of 79 patients in Pailin and 5 of 80 in Wang Pha and was not different between treatment arms (P = .68). Conclusions. Increasing the artesunate treatment dose up to 8 mg/kg/d or splitting the dose does not improve parasite clearance in either artemisinin resistant or more sensitive infections with P. falciparum. Clinical Trials Registration. ISRCTN15351875.
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- 2016
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29. High heritability of malaria parasite clearance rate indicates a genetic basis for artemisinin resistance in western Cambodia
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Jeff T. Williams, Arjen M. Dondorp, Duong Socheat, Tim J. Anderson, Debashish Das, Mallika Imwong, Nicholas J. White, Nicholas P. J. Day, Shalini Nair, Standwell Nkhoma, Kesinee Chotivanich, and Poravuth Yi
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Genotype ,Population ,Plasmodium falciparum ,Drug Resistance ,Biology ,Article ,Antimalarials ,Quantitative Trait, Heritable ,Genetic variation ,parasitic diseases ,medicine ,Immunology and Allergy ,Parasite hosting ,Humans ,Artemisinin ,Malaria, Falciparum ,education ,Genetics ,education.field_of_study ,Genetic Variation ,Heritability ,medicine.disease ,biology.organism_classification ,Twin study ,Artemisinins ,Infectious Diseases ,Cambodia ,Malaria ,medicine.drug ,Microsatellite Repeats - Abstract
In western Cambodia, malaria parasites clear slowly from the blood after treatment with artemisinin derivatives, but it is unclear whether this results from parasite, host, or other factors specific to this population. We measured heritability of clearance rate by evaluating patients infected with identical or nonidentical parasite genotypes, using methods analogous to human twin studies. A substantial proportion (56%-58%) of the variation in clearance rate is explained by parasite genetics. This has 2 important implications: (1) selection with artemisinin derivatives will tend to drive resistance spread and (2) because heritability is high, the genes underlying parasite clearance rate may be identified by genome-wide association.
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- 2016
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30. Artemisinin resistance in Plasmodium falciparum is associated with an altered temporal pattern of transcription
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Nicholas J. White, François Nosten, Poravuth Yi, Ramya Ramadoss, Duong Socheat, Peter R. Preiser, Margaret J. Mackinnon, Sachel Mok, Arjen M. Dondorp, Bruce Russell, Paul N. Newton, Mallika Imwong, Mayfong Mayxay, Kesinee Chotivanich, Nicholas P. J. Day, Joan Sim, Zbynek Bozdech, and Kek-Yee Liong
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Time Factors ,DNA Copy Number Variations ,Genotype ,Transcription, Genetic ,Plasmodium falciparum, in vivo artemisinin-resistance ,lcsh:QH426-470 ,lcsh:Biotechnology ,Plasmodium falciparum ,Drug Resistance ,Protozoan Proteins ,Drug resistance ,comparative genomics ,Antimalarials ,03 medical and health sciences ,comparative transcriptomics ,lcsh:TP248.13-248.65 ,parasitic diseases ,Genetics ,medicine ,Humans ,field isolates ,Trophozoites ,Artemisinin ,030304 developmental biology ,0303 health sciences ,biology ,030306 microbiology ,Gene Expression Profiling ,Genomics ,biology.organism_classification ,medicine.disease ,Phenotype ,Artemisinins ,3. Good health ,Gene expression profiling ,lcsh:Genetics ,DNA microarray ,Malaria ,Research Article ,Biotechnology ,medicine.drug - Abstract
Background Artemisinin resistance in Plasmodium falciparum malaria has emerged in Western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. To identify key features associated with the delayed parasite clearance phenotype, we employed DNA microarrays to profile the physiological gene expression pattern of the resistant isolates. Results In the ring and trophozoite stages, we observed reduced expression of many basic metabolic and cellular pathways which suggests a slower growth and maturation of these parasites during the first half of the asexual intraerythrocytic developmental cycle (IDC). In the schizont stage, there is an increased expression of essentially all functionalities associated with protein metabolism which indicates the prolonged and thus increased capacity of protein synthesis during the second half of the resistant parasite IDC. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of regulatory proteins such as transcription factors or chromatin remodeling associated proteins. In addition, there is a unique and uniform copy number variation pattern in the Cambodian parasites which may represent an underlying genetic background that contributes to the resistance phenotype. Conclusions The decreased metabolic activities in the ring stages are consistent with previous suggestions of higher resilience of the early developmental stages to artemisinin. Moreover, the increased capacity of protein synthesis and protein turnover in the schizont stage may contribute to artemisinin resistance by counteracting the protein damage caused by the oxidative stress and/or protein alkylation effect of this drug. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides insight to the complexities of the molecular basis of pathogens with drug resistance phenotypes in vivo.
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- 2016
31. National Malaria Prevalence in Cambodia: Microscopy Versus Polymerase Chain Reaction Estimates
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Didier Menard, Jan Bruce, Jean Popovici, Duong Socheat, Seshu Babu Vinjamuri, William O. Rogers, Walter R. J. Taylor, Sylvia Meek, Frédéric Ariey, Dysoley Lek, National Center for Parasitology, Entomology and Malaria Control [Phnom Penh, Cambodia] (CNM), National Institute of Public Health [Phnom Penh, Cambodge], Institut Pasteur du Cambodge, Réseau International des Instituts Pasteur (RIIP), Département Parasites et Insectes vecteurs - Department of Parasites and Insect Vectors, Institut Pasteur [Paris], Institut Cochin (IC UM3 (UMR 8104 / U1016)), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Service de parasitologie-mycologie [CHU Cochin], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Cochin [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), World Health Organization Lao People's Democratic Republic Office [Vientiane, Laos], Organisation Mondiale de la Santé / World Health Organization Office (OMS / WHO), London School of Hygiene and Tropical Medicine (LSHTM), Hôpitaux Universitaires de Genève (HUG), Mahidol Oxford Tropical Medicine Research Unit (MORU), University of Oxford [Oxford]-Mahidol University [Bangkok]-Wellcome Trust, US Naval Medical Research Unit n°2, We are grateful to the study participants and for the support of the National Institute of Health Research and Development of Indonesia, and of the Eijkman Institute., Institut Pasteur [Paris] (IP), University of Oxford-Mahidol University [Bangkok]-Wellcome Trust, and Wellcome Trust-Mahidol University [Bangkok]-University of Oxford [Oxford]
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Male ,Plasmodium vivax ,Prevalence ,Plasmodium malariae ,Polymerase Chain Reaction ,law.invention ,0302 clinical medicine ,law ,[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,MESH: Child ,030212 general & internal medicine ,Malaria, Falciparum ,Child ,Dried blood ,Polymerase chain reaction ,MESH: Plasmodium falciparum ,MESH: Plasmodium malariae ,Microscopy ,biology ,MESH: Malaria, Falciparum ,MESH: Infant, Newborn ,Articles ,MESH: Infant ,3. Good health ,MESH: Plasmodium vivax ,Infectious Diseases ,MESH: Young Adult ,Child, Preschool ,Female ,Cambodia ,medicine.medical_specialty ,MESH: Microscopy ,Adolescent ,Plasmodium falciparum ,030231 tropical medicine ,MESH: Malaria ,Young Adult ,03 medical and health sciences ,Virology ,Internal medicine ,parasitic diseases ,Malaria, Vivax ,medicine ,Humans ,MESH: Prevalence ,MESH: Adolescent ,MESH: Humans ,MESH: Cambodia ,MESH: Child, Preschool ,Infant, Newborn ,Infant ,MESH: Malaria, Vivax ,MESH: Polymerase Chain Reaction ,medicine.disease ,biology.organism_classification ,Confidence interval ,MESH: Male ,Malaria ,Parasitology ,MESH: Female - Abstract
International audience; Accurate information regarding malaria prevalence at national level is required to design and assess malaria control/elimination efforts. Although many comparisons of microscopy and polymerase chain reaction (PCR)-based methods have been conducted, there is little published literature covering such comparisons in southeast Asia especially at the national level. Both microscopic examination and PCR detection were performed on blood films and dried blood spots samples collected from 8,067 individuals enrolled in a nationwide, stratified, multistage, cluster sampling malaria prevalence survey conducted in Cambodia in 2007. The overall malaria prevalence and prevalence rates of Plasmodium falciparum, Plasmodium vivax, and Plasmodium malariae infections estimated by microscopy (N = 8,067) were 2.74% (95% confidence interval [CI]: 2.39-3.12%), 1.81% (95% CI: 1.53-2.13%), 1.14% (95% CI: 0.92-1.40%), and 0.01% (95% CI: 0.003-0.07%), respectively. The overall malaria prevalence based on PCR detection (N = 7,718) was almost 2.5-fold higher (6.31%, 95% CI: 5.76-6.89%, P < 0.00001). This difference was significantly more pronounced for P. falciparum (4.40%, 95% CI: 3.95-4.90%, P < 0.00001) compared with P. vivax (1.89%, 95% CI: 1.60-2.22%, P < 0.001) and P. malariae infections (0.22%, 95% CI: 0.13-0.35%, P < 0.0001). The significant proportion of microscopy-negative but PCR-positive individuals (289/7,491, 3.85%) suggest microscopic examination frequently underestimated malaria infections and that active case detection based on microscopy may miss a significant reservoir of infection, especially in low-transmission settings.
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- 2016
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32. High Prevalence of Opisthorchis viverrini Infection in a Riparian Population in Takeo Province, Cambodia
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Hoo Gn Jeoung, Sin Il Kang, Duong Socheat, Eun Hee Shin, Woon Mok Sohn, Eui Hyug Hoang, Jong-Yil Chai, Tai Soon Yong, Muth Sinuon, Dongmin Lee, Keeseon S. Eom, Keon Hoon Lee, Ji Hwa Lee, Jae Ku Cha, Yoon Hee Lee, Hyun Ju Woo, Keunhee Park, and Cheong Ha Yoon
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Adult ,Male ,Rural Population ,Veterinary medicine ,Adolescent ,prevalence ,Population ,Prevalence ,Biology ,Brief Communication ,Opisthorchiasis ,trematode ,Feces ,Young Adult ,Ascariasis ,parasitic diseases ,medicine ,Animals ,Humans ,Helminths ,Opisthorchis viverrini ,Child ,education ,Aged, 80 and over ,education.field_of_study ,Coinfection ,Opisthorchis ,Infant ,Middle Aged ,biology.organism_classification ,medicine.disease ,Infectious Diseases ,Cambodia (Takeo) ,Opisthorchis Viverrini Infection ,Child, Preschool ,Trichuris trichiura ,Female ,Parasitology ,Ascaris lumbricoides ,Cambodia - Abstract
Opisthorchis viverrini infection was found to be highly prevalent in 3 riverside villages (Ang Svay Chek A, B, and C) of the Prey Kabas District, Takeo Province. This area is located in the southern part of Cambodia, where the recovery of adult O. viverrini worms was recently reported. From May 2006 until May 2010, fecal examinations were performed on a total of 1,799 villagers using the Kato-Katz thick smear technique. In the 3 villages, the overall positive rate for helminth eggs ranged from 51.7 to 59.0% (av. 57.4%), and the percentage positive for O. viverrini was 46.4-50.6% (47.5%). Other helminths detected included hookworms (13.2%), echinostomes (2.9%), Trichuris trichiura (1.3%), Ascaris lumbricoides (0.6%), and Taenia spp. (0.06%). The prevalence of O. viverrini eggs appeared to reflect a lower infection in younger individuals (20 years). Men (50.4%) revealed a significantly higher (P=0.02) prevalence than women (44.3%). The Ang Svay Chek villages of the Prey Kabas District, Takeo Province, Cambodia have been confirmed to be a highly endemic area for human O. viverrini infection.
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- 2012
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33. Comparative phylogeography reveals a shared impact of pleistocene environmental change in shaping genetic diversity within nine Anopheles mosquito species across the Indo-Burma biodiversity hotspot
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Pe Than Htun, Thaung Hlaing, Duong Socheat, Damrongpan Thongwat, Simone Nambanya, Samantha M. O’Loughlin, Katy Morgan, Roger K. Butlin, Bin Chen, Pradya Somboon, Robert Verity, Anil Prakash, Mun Yik Fong, Trung Ho Dinh, Catherine Walton, and Yvonne-Marie Linton
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Phylogeography ,Genetic diversity ,Environmental change ,Ecology ,Evolutionary biology ,Threatened species ,Genetics ,Biodiversity ,Allopatric speciation ,Biology ,Ecology, Evolution, Behavior and Systematics ,Biodiversity hotspot ,Coalescent theory - Abstract
South-East Asia is one of the world's richest regions in terms of biodiversity. An understanding of the distribution of diversity and the factors shaping it is lacking, yet essential for identifying conservation priorities for the region's highly threatened biodiversity. Here, we take a large-scale comparative approach, combining data from nine forest-associated Anopheles mosquito species and using statistical phylogeographical methods to disentangle the effects of environmental history, species-specific ecology and random coalescent effects. Spatially explicit modelling of Pleistocene demographic history supports a common influence of environmental events in shaping the genetic diversity of all species examined, despite differences in species' mtDNA gene trees. Populations were periodically restricted to allopatric northeastern and northwestern refugia, most likely due to Pleistocene forest fragmentation. Subsequent southwards post-glacial recolonization is supported by a north-south gradient of decreasing genetic diversity. Repeated allopatric fragmentation and recolonization have led to the formation of deeply divergent geographical lineages within four species and a suture zone where these intraspecific lineages meet along the Thai-Myanmar border. A common environmental influence for this divergence was further indicated by strong support for simultaneous divergence within the same four species, dating to approximately 900 thousand years ago (kya). Differences in the geographical structuring of genetic diversity between species are probably the result of varying species' biology. The findings have important implications for conservation planning; if the refugial regions and suture zone identified here are shared by other forest taxa, the unique and high levels of genetic diversity they house will make these areas conservation priorities.
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- 2011
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34. Treatment coverage survey after a school-based mass distribution of mebendazole
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Duong Socheat, Kim Koporc, Nicholas C. Chesnaye, Els Mathieu, Muth Sinuon, Medical Informatics, APH - Methodology, APH - Health Behaviors & Chronic Diseases, APH - Quality of Care, APH - Aging & Later Life, and ACS - Pulmonary hypertension & thrombosis
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Male ,medicine.medical_specialty ,Pediatrics ,Coverage ,Adolescent ,Sanitation ,Veterinary (miscellaneous) ,Mebendazole ,Helminthiasis ,Deworming ,Household survey ,Environmental health ,Humans ,Medicine ,Anthelmintic ,Child ,Mass drug administration ,Anthelmintics ,Infection Control ,Schools ,School age child ,business.industry ,Soil-transmitted helminths ,Infant ,Treatment Outcome ,Infectious Diseases ,Child, Preschool ,Insect Science ,Tropical medicine ,Female ,Parasitology ,Health Services Research ,School-age children ,Cambodia ,business ,medicine.drug - Abstract
In efforts to reduce the global burden of soil transmitted helminth (STH) infections in school age children (SAC, 6-14 years old), Children Without Worms donates mebendazole to 8 countries with high prevalence of STH infections. Cambodia's national deworming program currently targets SAC through bi-annual school-based distributions of a single dose of mebendazole. A 30-cluster household survey was conducted in the rural province Kampot, to validate mebendazole treatment coverage in SAC and to assess the level of improved water supply and sanitation. Bi-annual primary school-based distributions proved to be an effective strategy in reaching school attending SAC, with treatment coverage rates between 84.1% and 88.8%. However, significantly lower rates (23.3-48.8%) were seen among SAC not enrolled in primary schools. Often members of the most marginalized families of the community, they are particularly at risk of STH infection. Methods to reach these children need to be explored to avoid treatment inequities.
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- 2011
35. Inter-specific gene flow dynamics during the Pleistocene-dated speciation of forest-dependent mosquitoes in Southeast Asia
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P. K. Saikia, Catherine Walton, Vas Dev, Katy Morgan, Pradya Somboon, Yvonne-Marie Linton, and Duong Socheat
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Sympatry ,Species complex ,biology ,Ecology ,Anopheles dirus ,Genetics ,Allopatric speciation ,Vicariance ,Parapatric speciation ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Coalescent theory ,Gene flow - Abstract
Tropical forests have undergone repeated fragmentation and expansion during Pleistocene glacial and interglacial periods, respectively. The effects of this repeated forest fragmentation in driving vicariance in tropical taxa have been well studied. However, relatively little is known about how often this process results in allopatric speciation, since it may be inhibited by recurrent gene flow during repeated secondary contact, or to what extent Pleistocene-dated speciation results from ecological specialization in the face of gene flow. Here, divergence times and gene flow between three closely-related mosquito species of the Anopheles dirus species complex endemic to the forests of Southeast Asia, are inferred using coalescent based Bayesian analysis. An Isolation with Migration model is applied to sequences of two mitochondrial and three nuclear genes, and 11 microsatellites. The divergence of An. scanloni has occurred despite unidirectional nuclear gene flow from this species into An. dirus. The inferred asymmetric gene flow may result from the unique evolutionary adaptation of An. scanloni to limestone karst habitat, and therefore the fitness advantage of this species over An. dirus in regions of sympatry. Mitochondrial introgression has led to the complete replacement of An. dirus haplotypes with those of An. baimaii through a recent (approximately 62 kya) selective sweep. Speciation of An. baimaii and An. dirus is inferred to have involved allopatric divergence throughout much of the Pleistocene. Secondary contact and bidirectional gene flow has occurred only within the last 100 000 years, by which time the process of allopatric speciation seems to have been largely completed.
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- 2010
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36. Cost-effectiveness of a successful schistosomiasis control programme in Cambodia (1995–2006)
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Emanuela Foglia, Umberto Restelli, Davide Croce, Antonio Montresor, Emanuele Porazzi, Muth Sinuon, and Duong Socheat
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Cost effectiveness ,Cost-Benefit Analysis ,Veterinary (miscellaneous) ,Discount points ,Article ,Young Adult ,Schistosomiasis control ,Environmental protection ,parasitic diseases ,medicine ,Animals ,Humans ,Schistosomiasis ,Infection control ,Socioeconomics ,Productivity ,health care economics and organizations ,Cost–benefit analysis ,business.industry ,Public health ,Cost-effectiveness analysis ,Middle Aged ,Infectious Diseases ,Insect Science ,Communicable Disease Control ,Female ,Parasitology ,Cambodia ,business - Abstract
Following preventive chemotherapy covering the entire population in the two endemic regions in Cambodia, the prevalence of schistosomiasis dropped from 77% in 1995 to 0.5% in 2003. The study presented here reports on the running cost of the control programme, and evaluates its cost-effectiveness and cost-benefit. Financial costs were assessed using data taken from the annual reports of the National Center for Malaria Control, the Cambodian institution responsible for the control activities. Other data were collected from interviews with provincial and district staff. The analysis was conducted from the point of views of the Cambodian Ministry of Health and that of the society, and the comparison was undertaken using the "do-nothing" option. The cost to treat an individual for the 9 years period of the implementation phase was 9.22 USD (1.02 per year), the cost for each severe infection avoided was 61.50 USD and 6531 USD for each death avoided. The drug cost corresponds on average to 17.34% of the programme's implementation cost. The cost of bringing one severely infected individual of productive age to complete productivity, was estimated at 114 USD and for 1 USD invested in the programme the return in increased productivity, for the economic system, was estimated to be 3.85 USD. The control programme demonstrated significant economical advantages. However, its costs are too high to be entirely supported by the Cambodian Ministry of Health.
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- 2010
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37. Plasmodium falciparum genome-wide scans for positive selection, recombination hot spots and resistance to antimalarial drugs
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Michael Waisberg, Shengfa Liu, Philip Awadalla, Xin-zhuan Su, Duong Socheat, Rachel A. Myers, Haibo Li, Polrat Wilairatana, Daniel E. Sturdevant, Sreng Sokunthea, Stephen F. Porcella, Xinhua Wang, Thomas E. Wellems, Kesinee Chotivanich, Fengzhen Ou, Guoqiao Li, Nicholas J. White, Stacy Ricklefs, Rick M. Fairhurst, Liwang Cui, May Ho, Suon Seila, Srivicha Krudsood, Jianbing Mu, Jianping Song, Hongying Jiang, and Rachanee Udomsangpetch
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Plasmodium falciparum ,030231 tropical medicine ,malaria ,Single-nucleotide polymorphism ,Genome-wide association study ,Drug resistance ,Biology ,Genome ,Article ,Antimalarials ,Inhibitory Concentration 50 ,03 medical and health sciences ,0302 clinical medicine ,single nucleotide polymorphism (SNP) ,parasitic diseases ,Genetics ,medicine ,Cluster Analysis ,Selection, Genetic ,Oligonucleotide Array Sequence Analysis ,030304 developmental biology ,Recombination, Genetic ,Comparative Genomic Hybridization ,0303 health sciences ,genome-wide association study ,drug resistance ,Geography ,Chromosome Mapping ,population structure ,DNA, Protozoan ,medicine.disease ,biology.organism_classification ,Antiparasitic agent ,recombination ,3. Good health ,SNP genotyping ,Genetic Loci ,Malaria - Abstract
Antimalarial drugs impose strong selective pressure on Plasmodium falciparum parasites and leave signatures of selection in the parasite genome; screening for genes under selection may suggest potential drug or immune targets. Genome-wide association studies (GWAS) of parasite traits have been hampered by the lack of high-throughput genotyping methods, inadequate knowledge of parasite population history and time-consuming adaptations of parasites to in vitro culture. Here we report the first Plasmodium GWAS, which included 189 culture-adapted P. falciparum parasites genotyped using a custom-built Affymetrix molecular inversion probe 3K malaria panel array with a coverage of approximately 1 SNP per 7 kb. Population structure, variation in recombination rate and loci under recent positive selection were detected. Parasite half-maximum inhibitory concentrations for seven antimalarial drugs were obtained and used in GWAS to identify genes associated with drug responses. This study provides valuable tools and insight into the P. falciparum genome.
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- 2010
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38. Spatial genetic structure ofAedes aegyptimosquitoes in mainland Southeast Asia
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Anil Prakash, Catherine Walton, Moh Seng Chang, Pradya Somboon, Sein Min, Willoughby Tun-Lin, Sein Thaung, Babaranda De Silva, Duong Socheat, To Setha, Yvonne Linton, Thaung Hlaing, and Okorie Anyaele
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biology ,Ecology ,Genetic heterogeneity ,Aedes aegypti ,medicine.disease ,biology.organism_classification ,Dengue fever ,Vector (epidemiology) ,Genetic structure ,Genetics ,medicine ,Spatial ecology ,Biological dispersal ,Microsatellite ,General Agricultural and Biological Sciences ,Ecology, Evolution, Behavior and Systematics - Abstract
Aedes aegypti mosquitoes originated in Africa and are thought to have spread recently to Southeast Asia, where they are the major vector of dengue. Thirteen microsatellite loci were used to determine the genetic population structure of A. aegypti at a hierarchy of spatial scales encompassing 36 sites in Myanmar, Cambodia and Thailand, and two sites in Sri Lanka and Nigeria. Low, but significant, genetic structuring was found at all spatial scales (from 5 to >2000 km) and significant FIS values indicated genetic structuring even within 500 m. Spatially dependent genetic-clustering methods revealed that although spatial distance plays a role in shaping larger-scale population structure, it is not the only factor. Genetic heterogeneity in major port cities and genetic similarity of distant locations connected by major roads, suggest that human transportation routes have resulted in passive long-distance migration of A. aegypti. The restricted dispersal on a small spatial scale will make localized control efforts and sterile insect technology effective for dengue control. Conversely, preventing the establishment of insecticide resistance genes or spreading refractory genes in a genetic modification strategy would be challenging. These effects on vector control will depend on the relative strength of the opposing effects of passive dispersal.
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- 2010
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39. Pupal sampling forAedes aegypti(L.) surveillance and potential stratification of dengue high-risk areas in Cambodia
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To Setha, Joshua Nealon, Duong Socheat, and Chang M. Seng
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Aedes ,education.field_of_study ,biology ,Population ,Public Health, Environmental and Occupational Health ,Outbreak ,Aedes aegypti ,biology.organism_classification ,medicine.disease ,Population density ,Dengue fever ,Infectious Diseases ,Geography ,Vector (epidemiology) ,Environmental health ,medicine ,Parasitology ,Rural area ,education - Abstract
Summary Objectives To identify and describe the distribution of dengue vectors and factors affecting this distribution in Cambodia, with a view to practicing rational, evidence-based dengue outbreak prevention activities. Methods Entomological survey with a questionnaire component in 100 randomly selected households in each of 13 clusters of high or low human population density of seven Cambodian provinces. Entomological and other indices were calculated, and statistical methods used to describe factors of potential outbreak risk. Results Aedes aegypti was the principle dengue vector in all clusters, making up 95.5% (20 555 of 21 325) of the Aedes pupae population. The majority of pupae were recovered either from large concrete water storage jars (16 230; 76.1%) or concrete water storage tanks (2819; 13.2%). There were small but significantly higher levels of dengue vector infestation in rural than urban areas. The mean pupae density over the survey was 16.4/house, which ranged between clusters from 5.2/house to 56.9/house. The ‘pupae-per-person’ index was 2.4 and 3.6 in urban and rural areas, respectively, and was independent of mean human population density or household water container distribution. Conclusions High populations of household-associated dengue vectors were present in all surveyed clusters. The highly skewed distribution of pupae in a limited number of key containers suggests adoption and further development of community-based control measures targeting these containers holds most potential chance of controlling dengue outbreaks in Cambodia.
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- 2009
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40. Importance of protection of antimalarial combination therapies
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Duong, Socheat, Lim, Pharath, Fandeur, Thierry, and Tsuyuoka, Reiko
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- 2004
41. Cost-effectiveness of annual targeted larviciding campaigns in Cambodia against the dengue vector Aedes aegypti
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Jose A. Suaya, Duong Socheat, Stefan Hoyer, Moh-Seng Chang, Donald S. Shepard, Ngan Chantha, Michael B. Nathan, and Mariana Caram
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medicine.medical_specialty ,education.field_of_study ,biology ,Cost effectiveness ,Population ,Public Health, Environmental and Occupational Health ,Annual average ,Aedes aegypti ,biology.organism_classification ,medicine.disease ,Medical care ,Dengue fever ,Infectious Diseases ,Geography ,Societal perspective ,Tropical medicine ,medicine ,Parasitology ,education ,Humanities - Abstract
Summary Objective To assess the cost-effectiveness (CE) of annual targeted larviciding campaigns from 2001 to 2005 against the dengue vector Aedes aegypti in two urban areas of Cambodia with a population of 2.9 million people. Methods The intervention under analysis consisted of annual larviciding campaigns targeting medium to large water storage containers in households and other premises. The CE compared the intervention against the hypothetical alternative of no intervention. The CE was calculated as the ratio of disability adjusted life years (DALYs) saved to the net cost of the intervention (in 2005 US dollars) by year. A sensitivity analysis explored the range of study parameters. Results The intervention reduced the number of dengue cases and deaths by 53%. It averted an annual average of 2980 dengue hospitalizations, 11 921 dengue ambulatory cases and 23 dengue deaths, resulting in a saving of 997 DALYs per year. The gross cost of the intervention was US$ 567 800 per year, or US$ 0.20 per person covered. As the intervention averted considerable medical care, the annual net cost of the intervention was US$ 312 214 (US$ 0.11 per person covered) from a public sector perspective and US$ 37 137 (US$ 0.01 per person covered) from a societal perspective. The resulting CE ratios were: US$ 313/DALY gained from the public perspective and US$ 37/DALY gained from the societal perspective. Even under the most conservative assumption, the intervention remained cost effective from both perspectives. Conclusions Annual, targeted larviciding campaigns appear to have been effective and cost-effective medium-term interventions to reduce the epidemiologic and economic burden of dengue in urban areas of Cambodia. Objectif Evaluer la rentabilite des campagnes annuelles utilisant des larvicides contre Aedes aegypti le vecteur de la dengue de 2001 a 2005 dans deux regions urbaines du Cambodge avec une population de 2,9 millions d’habitants. Methodes L’intervention analysee consistait en des campagnes annuelles utilisant des larvicides sur des moyens et grands recipients d’eau dans les menages et autres premisses. La mesure de la rentabilite a compare l’intervention par rapport a l’alternative hypothetique de non intervention. La rentabilite a ete calculee comme etant le rapport entre les annees de vie sauvees ajustees par l’incapacite (DALY) et le cout net de l’intervention par annee (valeur du dollars USA de 2005). Une analyse de sensibilite a explore la gamme des parametres d’etude. Resultats L’intervention a reduit le nombre de cas et de deces de la dengue de 53%. Elle a evite en moyenne 2980 hospitalisations, 11 921 cas ambulatoires et 23 deces par la dengue, avec pour resultat une economie de 997 DALY par an. Le cout brut de l’intervention etait de 567 800 dollars US par an soit 0,20 dollars US par personne couvert. Puisque l’intervention a evite un nombre considerable de soins medicaux, le cout net de l’intervention etait de 312 214 dollars US (0,11 dollars US par personne couvert) pour une perspective de secteur publique et de 37 137 dollars US (0,01 dollars US par personne couvert) pour une perspective sociale. Les rapports rentabilite resultantes etaient: 313 dollars US/DALY selon la perspective publique et de 37 dollars US/DALY selon la perspective sociale. Meme avec l’assomption la plus conservatrice, l’intervention est demeuree rentable selon les deux perspectives. Conclusions Les campagnes annuelles utilisant des larvicides semblent avoir ete des interventions efficaces et rentables a moyen terme pour reduire la charge epidemiologique et economique de la dengue dans des regions urbaines du Cambodge. Objetivo Evaluar la costo-efectividad de las campanas anuales de aplicacion de larvicidas contra el vector del dengue Aedes aegypti desde el 2001 y hasta el 2005 en dos areas urbanas de Cambodia con una poblacion de 2.9 millones de personas. Metodos La intervencion analizada consistia en campanas anuales de aplicacion de larvicidas sobre contenedores medianos a grandes utilizados para el almacenamiento de agua en hogares y otros lugares. La costo-efectividad (CE) comparo la intervencion frente a la alternativa hipotetica de no intervencion. La CE se calculo como los anos de vida ajustados por discapacidad (DALYs) ganados al costo neto de la intervencion (en dolares americanos del 2005) por ano. Un analisis de sensibilidad exploro el rango de los parametros del estudio. Resultados La intervencion redujo el numero de casos de dengue y de muertes en un 53%. Previno un promedio de 2980 hospitalizaciones por dengue, 11 921 casos ambulatorios de dengue, y 23 muertes por dengue, resultando en una ganancia de DALYs por ano. El coste bruto de la intervencion fue de US$ 567 800 por ano, o US$ 0.20 por persona cubierta. Puesto que la intervencion previno un cuidado medico considerable, el coste neto de la intervencion fue de US$ 312 214 (US$ 0.11 por persona cubierta) desde una perspectiva del sector publico y US$ 37 137 (US$ 0.01 por persona cubierta) desde una perspectiva social. Las proporciones de coste-efectividad resultantes fueron: US$ 313/DALY ganados desde una perspectiva publica y US$ 37/DALY ganados desde una perspectiva social. Aun bajo las asunciones mas conservadoras, la intervencion era costo efectiva desde ambas perspectivas. Conclusiones Las campanas anuales y dirigidas con larvicidas parecen haber sido efectivas, siendo intervenciones costo efectivas a medio plazo para reducir la carga epidemiologica y economica del dengue en areas urbanas de Cambodia.
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- 2007
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42. A randomized open study to assess the efficacy and tolerability of dihydroartemisinin-piperaquine for the treatment of uncomplicated falciparum malaria in Cambodia
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Duong Socheat, Elizabeth A. Ashley, M. Van Herp, A. Brockman, Bart Janssens, S. Uong, S. Nong, W. Van Damme, S. Chan, and L. Goubert
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Gynecology ,medicine.medical_specialty ,biology ,business.industry ,Mefloquine ,Public Health, Environmental and Occupational Health ,Plasmodium falciparum ,medicine.disease ,biology.organism_classification ,Surgery ,Open study ,chemistry.chemical_compound ,Infectious Diseases ,Dihydroartemisinin/piperaquine ,chemistry ,Tolerability ,Artesunate ,Tropical medicine ,medicine ,Parasitology ,business ,Malaria ,medicine.drug - Abstract
Summary Objectives To compare the efficacy and tolerability of dihydroartemisinin–piperaquine (DHA–PQP) with that of a 3-day regimen of mefloquine and artesunate (MAS3) for the treatment of uncomplicated falciparum malaria in Cambodia. Method Randomized open-label non-inferiority study over 64 days. Results Four hundred and sixty-four patients were included in the study. The polymerase chain reaction genotyping-adjusted cure rates on day 63 were 97.5% (95% confidence interval, CI, 93.8–99.3) for DHA–PQP and 97.5% (95% CI, 93.8–99.3) for MAS3, P = 1. There were no serious adverse events, but significantly more episodes of vomiting (P = 0.03), dizziness (P = 0.002), palpitations (P = 0.04), and sleep disorders (P = 0.03) reported in the MAS3 treatment group, consistent with the side-effect profile of mefloquine. Conclusions DHA–PQP was as efficacious as MAS3, but much better tolerated, making it more appropriate for use in a routine programme setting. This highly efficacious, safe and more affordable fixed-dose combination could become the treatment of choice for Plasmodium falciparum malaria in Cambodia. Objectifs Comparer l'efficacite et la tolerance du dihydroartemisinine-piperaquine (DHA–PQP) a celles d'un regime a base de mefloquine de trois jours (MAS3) pour le traitement de la malaria falciparum non compliquee au Cambodge. Methode Etude Randomisee ouverte de non inferiorite sur 64 jours. Resultats 464 patients ont ete inclus dans l’etude. Les taux guerison au jour 63 ajustes par les resultats du genotypage par la reaction en chaine de la polymerase etaient de 97,5% (IC95%: 93.8–99.3) pour le DHA–PQP et de 97,5% (IC95%: 93,8–99,3) pour le MAS3, P = 1. Il n'y avait aucun effet adverse serieux, mais de facon significative, des episodes de vomissement (P = 0,03), des vertiges (P = 0,002), des palpitations (P = 0,04), et des troubles de sommeil (P = 0.03) ont ete rapportes dans le groupe du traitement au MAS3, ce qui etait consistant avec les profiles d'effets secondaires du mefloquine. Conclusion le DHA–PQP etait aussi efficace que le MAS3, mais bien mieux tolere, le rendant ainsi plus approprie pour l'usage en routine dans le cadre d'un programme. Cette combinaison a dose fixe de grande efficacite, sure et plus accessible pourrait devenir le traitement de choix pour la malaria aPlasmodium falciparum au Cambodge. Objetivos Comparar la eficacia y la tolerabilidad de la dihidroartemisinina-piperaquina (DHA–PQP) con la de un regimen de 3 dias de mefloquina (MAS3), para el tratamiento de la malaria no complicada por falciparum en Cambodia Metodo Estudio aleatorizado, abierto, de no-inferioridad, durante 64 dias. Resultados Se incluyeron 464 pacientes en el estudio. Las tasas de curacion en el dia 63, ajustadas por genotipaje mediante PCR, fueron del 97.5% (95% IC: 93.8–99.3) para DHA–PQP y del 97.5% (95%IC: 93.8–99.3) para MAS3, P = 1. No se observaron eventos adversos serios, pero si se reporto un numero significativo de episodios de vomitos (P = 0.03), mareos (P = 0.002), palpitaciones (P = 0.04), y desordenes del sue,no (P = 0.03) entre el grupo de tratamiento con MAS3, algo consistente con el perfil de efectos secundarios de la mefloquina. Conclusiones La DHA–PQP fue tan eficaz como la MAS3, ademas de ser mejor tolerada, siendo mas apropiada para el uso dentro del marco de un programa de rutina. Esta combinacion de dosis fija, altamente eficaz, segura y mas asequible, podria convertirse en el tratamiento de eleccion para malaria por Plasmodium falciparum en Cambodia.
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- 2007
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43. Control of Schistosoma mekongi in Cambodia: results of eight years of control activities in the two endemic provinces
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Hajime Matsuda, Antonio Montresor, Hiroshi Ohmae, Muth Sinuon, Peter Odermatt, Reiko Tsuyuoka, Kevin Palmer, and Duong Socheat
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Adult ,Pediatrics ,medicine.medical_specialty ,Adolescent ,Endemic Diseases ,Mebendazole ,Helminthiasis ,Hepatosplenomegaly ,Schistosomiasis ,Article ,Praziquantel ,Schistosomicides ,Soil ,parasitic diseases ,Epidemiology ,Prevalence ,medicine ,Humans ,Child ,Aged ,biology ,business.industry ,Public Health, Environmental and Occupational Health ,General Medicine ,Middle Aged ,biology.organism_classification ,medicine.disease ,Surgery ,Infectious Diseases ,Child, Preschool ,Schistosoma mekongi ,Parasitology ,medicine.symptom ,Ascaris lumbricoides ,Cambodia ,business ,medicine.drug - Abstract
Summary In Cambodia, schistosomiasis is transmitted in the provinces of Kratie and Stung Treng where approximately 80 000 individuals are estimated to be at risk of infection. The baseline prevalence of infection was estimated to be between 73% and 88%, and cases of severe morbidity (hepatosplenomegaly, puberty retardation) and mortality were very common. In 1994, the Ministry of Health of Cambodia started schistosomiasis control applying universal chemotherapy with praziquantel (40 mg/kg). The coverage of the programme was between 62% and 86% for 8 years. This simple control measure resulted in the control of the disease: no cases were reported in 2004 and only three cases were reported in 2005. In addition, there are no longer reports of cases of severe morbidity due to schistosomiasis. Since the beginning of the control programme, a single dose of mebendazole (500 mg) has been combined with praziquantel during the mass chemotherapy; as a result the prevalence of Ascaris lumbricoides and hookworms dropped from 74.5% to 10% and from 86% to 40% respectively. The experience in Cambodia demonstrates that, with political commitment, control of parasitic diseases is achievable even in a situation of minimal resources. The programme represents a successful model for other developing countries.
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- 2007
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44. Efficacy of artemether?lumefantrine for the treatment of uncomplicated falciparum malaria in northwest Cambodia
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Sophoan Narann Top, Pascal Ringwald, Anna Annerberg, Pharath Lim, Niklas Lindegardh, Eva Christophel, Reiko Tsuyuoka, Duong Socheat, Mey Bouth Denis, Thierry Fandeur, and Poravuth Yi
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Adult ,Male ,medicine.medical_specialty ,Artemether/lumefantrine ,Adolescent ,Plasmodium falciparum ,Artesunate ,Lumefantrine ,Treatment failure ,Antimalarials ,chemistry.chemical_compound ,Parasitic Sensitivity Tests ,Animals ,Humans ,Medicine ,Treatment Failure ,Artemether ,Malaria, Falciparum ,Child ,Gynecology ,Fluorenes ,business.industry ,Artemether, Lumefantrine Drug Combination ,Significant difference ,Public Health, Environmental and Occupational Health ,medicine.disease ,Artemisinins ,Surgery ,Mefloquine ,Drug Combinations ,Treatment Outcome ,Infectious Diseases ,chemistry ,Ethanolamines ,Acute Disease ,Dietary Supplements ,Tropical medicine ,Plasma concentration ,Drug Therapy, Combination ,Female ,Parasitology ,business ,Sesquiterpenes ,Malaria ,medicine.drug - Abstract
Summary Objective To determine the efficacy of artemether–lumefantrine malaria treatment, as an alternative to artesunate + mefloquine, which is becoming ineffective in some areas of the Thai–Cambodian border. Methods Two studies were conducted to monitor the efficacy of artemether–lumefantrine in Sampov Lun referral hospital, Battambang Province, in 2002 and 2003, and one study was conducted to assess the efficacy of mefloquine + artesunate in 2003 for comparison. The studies were performed according to the WHO standardized protocol with a follow-up of 28 days. The therapeutic efficacy tests were complemented with in vitro tests and in 2003, with the measurement of lumefantrine plasma concentration at day 7 for the patients treated with artemether–lumefantrine. Results A total of 190 patients were included: 55 were treated with artemether–lumefantrine in 2002 (AL2002), 80 with artemether–lumefantrine and food supplementation in 2003 (AL2003) and 55 with artesunate + mefloquine in 2003 (AM2003). With the per-protocol analysis, the cure rate was 71.1% in study AL2002, 86.5% in study AL2003 and 92.4% in study AM2003. All the data were PCR corrected. The artemether–lumefantrine cure rate was unexpectedly low in 2002, but it increased with food supplementation in 2003. There was a significant difference (P = 0.02) in lumefantrine plasma concentrations between adequate clinical and parasitological responses and treatment failure cases. In vitro susceptibility to lumefantrine was reduced for isolates sampled from patients presenting with treatment failure, but the difference was not statistically different from isolates sampled from patients who were successfully treated. Conclusion Treatment failure cases of artemether–lumefantrine are most probably because of low levels of lumefantrine blood concentration. Further investigations are necessary to determine whether resistance of Plasmodium falciparum isolates to lumefantrine is present in the region. Objectif Determiner l'efficacite de l'artemether–lumefantrine pour le traitement paludisme en tant qu'alternative a l'artesunate + mefloquine qui devient de plus en plus inefficace dans certaines zones dans la frontiere Thailando–Cambodgienne. Methodes Deux etudes ont ete menees pour mesurer l'efficacite de l'artemether–lumefantrine dans l'hopital de reference de Sampov Lun dans la province de Battambang en 2002 et 2003 et, dans un but de comparaison, une etude a aussi ete menee pour evaluer l'efficacite de l'artesunate + mefloquine en 2003. Les etudes ont ete menees selon les protocoles standardises de l'OMS avec un suivi de 28 jours. Les tests d'efficacite therapeutique ont ete complementes par des tests in vitro et, en 2003 par la mesure de la concentration plasmatique de lumefantrine au jour 7 pour les patients traites a l'artemether–lumefantrine. Resultats Au total 190 patients ont ete inclus dans l’etude parmi lesquels 55 ont ete traites a l'artemether–lumefantrine en 2002 (AL2002), 80 a l'artemether–lumefantrine en plus d'un complement de nourriture en 2003 (AL2003) et 55 a l'artesunate + mefloquine en 2003 (AM2003). L'analyse suivant un protocole standard a revele un taux de guerison de 71,1% pour AL2002, 86,5% pour AL2003 et 92,4% pour AM2003. Toutes les donnees ont ete ajustees avec les resultats de la PCR. Le taux de guerison pour l'artemether–lumefantrine s'est avere bas de facon inattendue en 2002 mais il a augmente avec le complement de nourriture en 2003. Il y avait une difference significative (p = 0,02) pour les concentrations plasmatiques de lumefantrine entre d'une part les reponses cliniques et parasitologiques adequates et d'autre part les cas d’echec therapeutique. La susceptibilite in vitro pour la lumefantrine etait reduite pour les souches isolees de patients presentant un echec therapeutique mais les valeurs n’etaient pas statistiquement differentes de celles de souches isolees de patients traites avec succes. Conclusion Les cas d’echec therapeutique a l'artemether–lumefantrine sont plus probablement dus a des concentrations sanguines basses de lumefantrine. Des investigations supplementaires sont necessaires pour determiner s'il existe une resistance de P. falciparuma la lumefantrine dans la region. Objetivo Determinar la eficacia del tratamiento de malaria con artemeter-lumefantrina como alternativa al artesunato + mefloquina, el cual esta dejando de ser efectivo en algunas areas de la frontera entre Tailanda y Cambodia. Metodos Se llevaron a cabo dos estudios para monitorizar la eficacia de artemeter-lumefantrina en el hospital de referencia de Sampov Lun, provincia de Battambang, entre el 2002 y 2003, asi como un estudio durante el 2003, y a modo de comparacion, para evaluar la eficacia de la mefloquina + artesunato. Estos estudios se realizaron siguiendo el protocolo estandar de la OMS con un seguimiento de 28 dias. Las pruebas de eficacia terapeutica se complementaron con pruebas in vitro y, durante el 2003, con la medicion de la concentracion de lumefantrina en plasma en el dia 7 para los pacientes tratados con artemeter-lumefantrina. Resultados Se incluyeron 190 pacientes: 55 fueron tratados con artemeter-lumefantrina en el 2002 (AL2002), 80 con artemeter-lumefantrina y suplementacion alimenticia en el 2003 (AL2003), y 55 con artesunato + mefloquina en el 2003. Con el analisis por protocolo, la tasa de curacion fue de 71.1% en el estudio AL2002, 86.5% en el estudio AL2003, y 92.4% en el estudio AM2003. Todos los datos fueron corregidos mediante PCR. La tasa de curacion para el tratamiento con artemeter-lumefantrina fue sorprendentemente baja en el 2002, pero aumento con la suplementacion alimenticia en el 2003. Se encontro una diferencia significativa (p = 0.02) en las concentraciones de lumefantrina en plasma entre casos con una respuesta clinica y parasitologica adecuadas y aquellos con fallo terapeutico. La susceptibilidad in vitro frente a la lumefantrina se redujo para cepas aisladas de pacientes que presentaban fallo en el tratamiento, pero la diferencia no era estadisticamente significativa de aquella para cepas aisladas de pacientes que hubiesen respondido adecuadamente al tratamiento. Conclusions Los casos de fallo terapeutico con artemeter-lumefantrina probablemente son debidos a bajos niveles de concentracion de lumefantrina en la sangre. Se necesitan mas estudios para determinar si existe resistencia a la lumefantrina entre las cepas de P. falciparum de la region.
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- 2006
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45. Residual Antimalarial Concentrations before Treatment in Patients with Malaria from Cambodia: Indication of Drug Pressure
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Hodel, Eva Maria, Genton, Blaise, Zanolari, Boris, Mercier, Thomas, Duong, Socheat, Beck, Hans-Peter, Olliaro, Piero, Decosterd, Laurent Arthur, Ariey, Frédéric, Hodel, Eva Maria, Genton, Blaise, Zanolari, Boris, Mercier, Thomas, Duong, Socheat, Beck, Hans-Peter, Olliaro, Piero, Decosterd, Laurent Arthur, and Ariey, Frédéric
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Background. The Thai-Cambodian border has been known as the origin of antimalarial drug resistance for the past 30 years. There is a highly diverse market for antimalarials in this area, and improved knowledge of drug pressure would be useful to target interventions aimed at reducing inappropriate drug use. Methods. Baseline samples from 125 patients with falciparum malaria recruited for 2 in vivo studies (in Preah Vihear and Pursat provinces) were analyzed for the presence of 14 antimalarials in a single run, by means of a liquid chromatography-tandem mass spectrometry assay. Results. Half of the patients had residual drug concentrations above the lower limit of calibration for at least 1 antimalarial at admission. Among the drugs detected were the currently used first-line drugs mefloquine (25% and 35% of patients) and piperaquine (15% of patients); the first-line drug against vivax malaria, chloroquine (25% and 41% of patients); and the former first-line drug, quinine (5% and 34% patients). Conclusions. The findings demonstrate that there is high drug pressure and that many people still seek treatment in the private and informal sector, where appropriate treatment is not guaranteed. Promotion of comprehensive behavioral change, communication, community-based mobilization, and advocacy are vital to contain the emergence and spread of parasite resistance against new antimalarials
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- 2017
46. Assessment of disease and infection of lymphatic filariasis in Northeastern Cambodia
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Tol Bunkea, Peter Odermatt, Duong Socheat, Boravong Bin, and Rithea Leang
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Physical examination ,Elephantiasis ,medicine.disease_cause ,Sensitivity and Specificity ,Microfilaria ,Brugia malayi ,Filariasis ,Age Distribution ,Elephantiasis, Filarial ,Surveys and Questionnaires ,Internal medicine ,parasitic diseases ,medicine ,Animals ,Humans ,Wuchereria bancrofti ,Child ,Disease burden ,Lymphatic filariasis ,Aged ,Aged, 80 and over ,Leg ,medicine.diagnostic_test ,biology ,business.industry ,Public Health, Environmental and Occupational Health ,Middle Aged ,medicine.disease ,biology.organism_classification ,Surgery ,Infectious Diseases ,Child, Preschool ,Scrotum ,Patient Compliance ,Female ,Parasitology ,Cambodia ,business - Abstract
We assessed the filariasis disease burden in four northeastern provinces of Cambodia by using and validating a key-informant questionnaire, consisting of four questions, with pictures of patients with leg elephantiasis and hydrocoele. The questionnaire was distributed and collected through the school, health and administrative systems. Validation surveys included clinical examination, a card test for W. bancrofti (ICT Filariasis card test, AMRAD) and night blood finger prick examination of patients reported with clinical elephantiasis. Only 48.0% of questionnaires were returned. A total of 220 patients were reported, mostly from Stung Treng (36.8%) and Rattanakiri provinces (35.0%). Key-informants reported patients with lymphatic filariasis with a sensitivity of 85.7% for leg and 97.0% for scrotum morbidity, and with a specificity of 95.6%. However, substantial over-reporting resulted in very low positive predictive values for elephantiasis of 19.4% for legs and of 23.7% for the scrotum. As 97.4% of patients with clinical lymphatic filariasis were older than 40 years, the diagnostic performance of the questionnaire would be improved by restricting its use to that age group. About 0.7% of 3490 W. bancrofti card tests were positive; the prevalence was 1.94% (12/618) in Rattanakiri, 0.38% (4/1055) in Stung Treng and 0.22% (2/919) in Preah Vihear. W. bancrofti microfilaria were identified in blood from two patients in Rattanakiri (0.32%) and from one patient in Stung Treng (0.09%). Brugia malayi microfilaria were identified in blood from five patients in Rattanakiri (0.81%) only. No patients with microfilariaemia were identified in Preah Vehear. In Mondulkiri province all investigations (card test, night blood examination, clinical examination) for lymphatic filariasis were negative. Our findings confirm the usefulness of key-informant questionnaire for the identification of filariasis patients provided that high adherence can be achieved. Lymphatic filariasis infection and disease is present in northern Cambodian provinces but the burdens of disease and infection are relatively low. These results are being used in the implementation of the national control programme for lymphatic filariasis.
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- 2004
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47. Schistosomiasis mekongi: from discovery to control
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Masashi Kirinoki, Muth Sinuon, Hajime Matsuda, Jun Matsumoto, Hiroshi Ohmae, Yuichi Chigusa, and Duong Socheat
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Adolescent ,Snails ,Fresh Water ,Schistosomiasis ,Ultrasonographic examination ,Serology ,Environmental health ,parasitic diseases ,Prevalence ,medicine ,Mekong river ,Animals ,Humans ,Neotricula aperta ,Child ,Ultrasonography ,biology ,Transmission (medicine) ,biology.organism_classification ,medicine.disease ,Praziquantel ,Infectious Diseases ,Laos ,Child, Preschool ,Schistosoma mekongi ,Immunology ,Schistosoma ,Parasitology ,Cambodia ,medicine.drug - Abstract
In the Mekong River basin, the first case of schistosomiasis was reported in 1957. In the 1960s, endemic areas of the infection, of which profiles were similar to those of schistosomiasis japonica, were discovered in Khong Island, Laos, to Kratie province, Cambodia. A new intermediate snail host; Neotricula aperta was identified and the Mekong strain of schistosome was elevated to a new species: Schistosoma mekongi in 1978. Baseline epidemiological surveillance was performed and schistosomiasis mekongi was described as a public health implication in the middle Mekong River basin. Because of political and economical confusion, endemic situation had become worse, and no control program had been implemented until mass treatment program with praziquantel on Khong Island in 1983. Since then, the prevalence of S. mekongi infection has rapidly decreased in each endemic area. Serological diagnosis has been useful to detect new but low endemic foci. Clinical manifestations of S. mekongi infection are similar to those of S. mansoni and S. japonicum infections. As the reduction of prevalence and intensity of S. mekongi infection, morbidity due to the disease has changed, and ultrasonographic examination is now useful to evaluate morbidity due to schistosomiasis mekongi. Transmission of the disease occurs in a couple of months during low water season. Control of N. aperta is difficult and long-lasting effective control measurements have, so far, not been available. In the next step for controling S. mekongi infection, mass treatment should be continued, and it is needed to combine other appropriate control activities.
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- 2004
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48. A comparative study of dihydroartemisinin compounds in treatment of uncomplicated falciparum malaria in Kampong of Cambodia
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Duong Socheat, Song Jian-ping, and Suou Seila
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medicine.medical_specialty ,Abdominal pain ,Low toxicity ,Nausea ,business.industry ,medicine.medical_treatment ,Dihydroartemisinin ,General Medicine ,medicine.disease ,Gastroenterology ,Clearance time ,Regimen ,Complementary and alternative medicine ,Tolerability ,Internal medicine ,Anesthesia ,parasitic diseases ,medicine ,Pharmacology (medical) ,medicine.symptom ,business ,Malaria - Abstract
Objective: To compare the safety and efficacy of two compounds of dihydroartemisinin (DHA)—Artekin and Artekin (T) in the treatment of uncomplicated falciparum malaria.Methods: The regimen of 8-tablet for 2 days of Artekin and Artekin (T) were applied to 100 patients with uncomplicated falciparum malaria, who were randomly divided into two groups. Each group contained 50 cases. The cure rate, the mean parasites clearance time, the mean fever clearance and side-effects were observed to assess the safety and efficacy of the compounds used.Results: The mean parasites clearance time was 31.7±9.0 hours in the Artekin group and 32.8±8.8 hours in Artekin (T) group respectively; the mean fever clearance time was 12. 7±7. 2 hours in Artekin group and 16. 5±7. 9 hours in Artekin (T) group; there were no recrudescence case in both groups within the 28 days of follow-up, the cure rates in Artekin group and Artekin (T) groups were 100%. It indicated that the tolerability of both compounds were very good, the side-effects such as nausea, abdominal pain were mild and self-limited.Conclusion: The study preliminarily indicated that the DHA and PQ compounds were of high efficacy, rapid acting and low toxicity. Artekin is very promising as a cheap, simple, effective treatment for multi-resistance malaria in Cambodia.
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- 2003
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49. Baseline data of parasite clearance in patients with falciparum malaria treated with an artemisinin derivative : an individual patient data meta-analysis
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WWARN Parasite Clearance Study Group, Abdulla, Salim, Ashley, Elizabeth A, Bassat, Quique, Bethell, Delia, Björkman, Anders, Borrmann, Steffen, D'Alessandro, Umberto, Dahal, Prabin, Day, Nicholas P, Diakite, Mahamadou, Djimde, Abdoulaye A, Dondorp, Arjen M, Duong, Socheat, Edstein, Michael D, Fairhurst, Rick M, Faiz, M Abul, Falade, Catherine, Flegg, Jennifer A, Fogg, Carole, Gonzalez, Raquel, Greenwood, Brian, Guérin, Philippe J, Guthmann, Jean-Paul, Hamed, Kamal, Hien, Tran Tinh, Htut, Ye, Juma, Elizabeth, Lim, Pharath, Mårtensson, Andreas, Mayxay, Mayfong, Mokuolu, Olugbenga A, Moreira, Clarissa, Newton, Paul, Noedl, Harald, Nosten, Francois, Ogutu, Bernhards R, Onyamboko, Marie A, Owusu-Agyei, Seth, Phyo, Aung Pyae, Premji, Zul, Price, Ric N, Pukrittayakamee, Sasithon, Ramharter, Michael, Sagara, Issaka, Se, Youry, Suon, Seila, Stepniewska, Kasia, Ward, Stephen A, White, Nicholas J, and Winstanley, Peter A
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Male ,Artemether/lumefantrine ,Social and Clinical Pharmacy ,Drug Resistance ,Physiology ,Parasitemia ,Drug resistance ,chemistry.chemical_compound ,Medicine ,Parasite hosting ,Artemisinin ,Malaria, Falciparum ,Child ,Diagnosis & treatment ,Clinical Trials as Topic ,Surveillance, monitoring, evaluation ,biology ,Public Health, Global Health, Social Medicine and Epidemiology ,Middle Aged ,Artemisinins ,3. Good health ,Infectious Diseases ,Blood ,Artemisinin resistance ,Child, Preschool ,Female ,medicine.drug ,Adult ,endocrine system ,Adolescent ,Plasmodium falciparum ,Antimalarials ,Young Adult ,Health Sciences ,parasitic diseases ,Animals ,Humans ,Aged ,Parasite clearance ,business.industry ,Research ,Samhällsfarmaci och klinisk farmaci ,Infant ,medicine.disease ,biology.organism_classification ,Malaria ,Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi ,chemistry ,Artesunate ,Immunology ,Parasitology ,business - Abstract
Background Artemisinin resistance in Plasmodium falciparum manifests as slow parasite clearance but this measure is also influenced by host immunity, initial parasite biomass and partner drug efficacy. This study collated data from clinical trials of artemisinin derivatives in falciparum malaria with frequent parasite counts to provide reference parasite clearance estimates stratified by location, treatment and time, to examine host factors affecting parasite clearance, and to assess the relationships between parasite clearance and risk of recrudescence during follow-up. Methods Data from 24 studies, conducted from 1996 to 2013, with frequent parasite counts were pooled. Parasite clearance half-life (PC1/2) was estimated using the WWARN Parasite Clearance Estimator. Random effects regression models accounting for study and site heterogeneity were used to explore factors affecting PC1/2 and risk of recrudescence within areas with reported delayed parasite clearance (western Cambodia, western Thailand after 2000, southern Vietnam, southern Myanmar) and in all other areas where parasite populations are artemisinin sensitive. Results PC1/2 was estimated in 6975 patients, 3288 of whom also had treatment outcomes evaluate d during 28–63 days follow-up, with 93 (2.8 %) PCR-confirmed recrudescences. In areas with artemisinin-sensitive parasites, the median PC1/2 following three-day artesunate treatment (4 mg/kg/day) ranged from 1.8 to 3.0 h and the proportion of patients with PC1/2 >5 h from 0 to 10 %. Artesunate doses of 4 mg/kg/day decreased PC1/2 by 8.1 % (95 % CI 3.2–12.6) compared to 2 mg/kg/day, except in populations with delayed parasite clearance. PC1/2 was longer in children and in patients with fever or anaemia at enrolment. Long PC1/2 (HR = 2.91, 95 % CI 1.95–4.34 for twofold increase, p
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- 2015
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50. Presence of Anopheles culicifacies B in Cambodia established by the PCR-RFLP assay developed for the identification of Anopheles minimus species A and C and four related species
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W. Van Bortel, Thierry Backeljau, Ralph E. Harbach, P Roelants, Duong Socheat, Marc Coosemans, and T. Sochanta
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Species complex ,Entomology ,General Veterinary ,Zoology ,Biology ,biology.organism_classification ,law.invention ,Sensu ,law ,Insect Science ,parasitic diseases ,Genotype ,Botany ,Parasitology ,Internal transcribed spacer ,Restriction fragment length polymorphism ,Anopheles culicifacies ,Ecology, Evolution, Behavior and Systematics ,Polymerase chain reaction - Abstract
A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay developed for identification of five species of the Anopheles minimus Theobald group and a related mosquito species of the Myzomyia Series (Diptera: Culicidae) was applied to morphologically identified adult female specimens collected in Ratanakiri Province, north-eastern Cambodia. In addition to finding An. aconitus Donitz, An. minimus species A and An. pampanai Buttiker & Beales, some specimens showed a new restriction banding pattern. Siblings of specimens that exhibited this new PCR-RFLP pattern were morphologically identified as An. culicifacies James sensu lato. Based on nucleotide sequences of the ribonuclear DNA internal transcribed spacer 2 region (ITS2) and the mitochondrial cytochrome oxidase I gene (COI), these specimens were recognized as An. culicifacies species B (sensu Green & Miles, 1980), the first confirmed record of the An. culicifacies complex from Cambodia. This study shows that the PCR-RFLP assay can detect species not included in the initial set-up and is capable of identifying at least seven species of the Myzomyia Series, allowing better definition of those malaria vector and non-vector anophelines in South-east Asia.
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- 2002
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