Publications (36)90.22 Total impact
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Article: Evaluation of a rapid colorimetric field test to assess the effective life of long-lasting insecticide-treated mosquito nets in the Lao PDR.
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ABSTRACT: BACKGROUND: Malaria morbidity and mortality have been significantly reduced through the proper use of insecticide-treated mosquito nets, but the extra protection afforded by the insecticide diminishes over time. The insecticide depletion rates vary according to location where wash frequency and wear are influenced by cultural habits as well as the availability of water. Monitoring of available insecticides on the net surface is essential for determining the effective life of the net. Therefore, a rapid and inexpensive colorimetric field test for cyanopyrethroids (Cyanopyrethroid Field Test or CFT) was used to measure surface levels of deltamethrin on insecticide-coated polyester nets (PowerNetsTM) in rural Lao PDR over a two-year period. METHODS: Net surface levels of deltamethrin were measured by wiping the net with filter paper and measuring the adsorbed deltamethrin using the CFT. A relationship between surface levels of deltamethrin and whole net levels was established by comparing results of the CFT with whole levels assayed by high-performance liquid chromatography (HPLC). An effective deltamethrin surface concentration (EC80) was determined by comparing mosquito mortality (WHO Cone Test) with CFT and HPLC results. Five positions (roof to bottom) on each of 23 matched nets were assayed for deltamethrin surface levels at 6, 12, and 24 months. Mosquito mortality assays (WHO Cone Tests) were performed on a subset of eleven 24-month old nets and compared with the proportion of failed nets as predicted by the CFT. RESULTS: At six months, the nets retained about 80% of the baseline (new net) levels of deltamethrin with no significant differences between net positions. At 12 months, ~15-40%, and at 24 months <10% of deltamethrin was retained on the nets, with significant differences appearing between positions. Results from the CFT show that 93% of the nets failed (deltamethrin surface levels </= EC80) at 24 months. This value is in agreement with 91% failure as determined by the WHO Cone Test on a subset of 11 nets. The CFT results show that 50% of the nets from Laos failed at 12 months of normal use. CONCLUSION: The CFT is a useful and accurate indicator of net efficacy and may be substituted for mosquito bioassays.Malaria Journal 02/2013; 12(1):57. · 3.19 Impact Factor -
Article: Efficacy of artemether-lumefantrine, the nationally-recommended artemisinin combination for the treatment of uncomplicated falciparum malaria, in southern Laos.
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ABSTRACT: BACKGROUND: The Lao Government changed the national policy for uncomplicated Plasmodium falciparum malaria from chloroquine to artemether-lumefantrine (AL) in 2005. Since then, no information on AL efficacy has been reported. With evidence of resistance to artemisinin derivatives in adjacent Cambodia, there has been a concern as to AL efficacy. Monitoring of AL efficacy would help the Lao Government to make decisions on appropriate malaria treatment. METHODS: The efficacy of a three-day, twice daily oral artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Xepon District, Savannakhet Province, southern Laos was studied over 42 days follow-up. This was part of a trial of thiamin supplementation in falciparum malaria. RESULTS: Of 630 patients with P. falciparum enrolled in the trial of thiamin treatment, 549 (87%, 357 children [less than or equal to]15 years and 192 adults) were included in this study. The per protocol 42-day cure rates were 97% (524/541) [96% (337/352) for children and 99% (187/189) for adults, p = 0.042]. By conventional intention-to-treat analysis, the 42-day cure rates adjusted for re-infection, were 97% (532/549) [96% (342/357) in children and 99% (190/192) in adults, p = 0.042]. The proportion of patients who remained parasitaemic at day 1 after treatment was significantly higher in children [33% (116/356)] compared to adults [15% (28/192)] (p < 0.001) and only one adult patient had detectable parasitaemia on day 2. There were no serious adverse events. Potential side effects after treatment were reported more commonly in adults (32%) compared to children (15%) (p < 0.001). Patients with recrudescent infections were significantly younger, had longer mean time to fever clearance, and had longer median time to parasite clearance compared to those who were cured. CONCLUSIONS: The current nationally-recommended anti-malarial treatment (artemether-lumefantrine) remains highly efficacious for the treatment of uncomplicated falciparum malaria five years after introduction in Laos. Regular monitoring is required in case artemisinin-resistant P. falciparum parasites should appear. Trial registration ISRCTN85411059.Malaria Journal 06/2012; 11(1):184. · 3.19 Impact Factor -
Article: No evidence for spread of Plasmodium falciparum artemisinin resistance to Savannakhet Province, Southern Laos.
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ABSTRACT: We conducted an open-label, randomized clinical trial to assess parasite clearance times (PCT) and the efficacy of 4 mg/kg (group 1, n = 22) and 2 mg/kg (group 2, n = 22) of oral artesunate for three days followed by artemether-lumefantrine in patients with uncomplicated Plasmodium falciparum malaria at Xepon Interdistrict Hospital, Savannakhet Province in southern Laos. Slides were read in duplicate. The overall mean (95% confidence interval; range) PCT in hours was 23.2 (21.2-25.3; 12-46) and 22.4 (20.3-24.5; 12-46) for the first and second microscopists, respectively (P = 0.57). Ten (23%) patients remained parasitemic on day 1 after treatment (4 [18%] in group 1 and 6 [27%] in group 2; P = 0.47). No patient had patent asexual parasitemia on the second and third days of treatment. The 42-day polymerase chain reaction-corrected cure rates were 100% in both treatment groups. Serious adverse events did not develop during or after treatment in any patients. In conclusion, no evidence of P. falciparum in vivo resistance to artesunate was found in southern Laos.The American journal of tropical medicine and hygiene 03/2012; 86(3):403-8. · 2.59 Impact Factor -
Article: Efficacy of mefloquine treatment and genetic profiles in uncomplicated Plasmodium falciparum malaria in southern Lao PDR.
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ABSTRACT: We conducted a 28-day follow-up of 17 Laotian patients diagnosed with uncomplicated Plasmodium falciparum malaria treated with mefloquine (Mephaquine, MQ) alone to determine the efficacy. All patients were completely cured with MQ, without reappearance of asexual stage parasitemia at follow-up. Of the 7 isolates tested for genotypic analysis, one isolate was a Y86 mutant type of the pfmdr1 gene, the others were N86 wild. These findings suggest no MQ resistance in the study area possibly because the drug is rarely used in southern Lao PDR.The Southeast Asian journal of tropical medicine and public health 07/2011; 42(4):759-63. · 0.60 Impact Factor -
Article: The efficacy and physical condition of olyset insecticide-treated nets after 5 years use in rural Lao PDR.
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ABSTRACT: We assessed the insecticidal efficacy of Olyset nets after 5 years of use in rural villages of Lao PDR and evaluated the relationship between the physical condition of the nets and their insecticidal effect. Our results showed that most of the Olyset nets remained effective after 5 years of use; however, there was no significant relationship between the physical condition of the nets (ie, presence of holes, level of stains) and the insecticidal effect. The presence of large holes in polyester nets compared to the Olyset nets suggest the Olyset nets are stronger; however, nearly half of Olyset nets had small holes or had been previously repaired. Interestingly, the insecticide concentration and knockdown (KD) rate for 3 stored nets was low compared to the other nets routinely used in the house. To maintain the effectiveness of Olyset nets in rural villages of Lao PDR and other areas, residents should be advised to repair and store the nets appropriately and avoid exposure to high temperatures and direct sunlight for long periods.The Southeast Asian journal of tropical medicine and public health 03/2011; 42(2):268-73. · 0.60 Impact Factor -
Article: A phase III, randomized, non-inferiority trial to assess the efficacy and safety of dihydroartemisinin-piperaquine in comparison with artesunate-mefloquine in patients with uncomplicated Plasmodium falciparum malaria in southern Laos.
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ABSTRACT: We conducted an open, randomized clinical trial of oral dihydroartemisinin-piperaquine (DP) versus artesunate-mefloquine (AM) in 300 patients in Laos with uncomplicated Plasmodium falciparum malaria as part of a multicentre study in Asia. Survival analysis and adjustment for re-infection showed that the 63-day cure rates (95% confidence interval [CI]) were 100% for AM and 99.5% (96.4-99.8%) for DP. The 63-day cure rates per protocol were 99% (97 of 98) for AM and 99.5% (196 of 197) for DP (P = 0.55). The difference (AM minus DP) in cure rates (95% CI) was -0.5% (-5.1 to 2.0%), which is within the 5% non-inferiority margin. The median fever and parasite clearance times were also similar for AM and DP. The proportion of patients with at least one recorded potential adverse event was significantly higher in the AM group (38 of 87, 44%) than in the DP group (57 of 182, 31%) (relative risk = 0.6, 95% CI = 0.4-0.9; P = 0.04). Dihydroartemisinin-piperaquine is not inferior to AM in the treatment of uncomplicated P. falciparum malaria in Laos and is associated with fewer adverse effects. The results of this study were similar to those of the larger multicentre study.The American journal of tropical medicine and hygiene 12/2010; 83(6):1221-9. · 2.59 Impact Factor -
Article: High heterogeneity in Plasmodium falciparum risk illustrates the need for detailed mapping to guide resource allocation: a new malaria risk map of the Lao People's Democratic Republic.
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ABSTRACT: ABSTRACT: BACKGROUND: Accurate information on the geographical distribution of malaria is important for efficient resource allocation. The Lao People's Democratic Republic has experienced a major decline in malaria morbidity and mortality in the past decade. However, efforts to respond effectively to these changes have been impeded by lack of detailed data on malaria distribution. In 2008, a countrywide survey on Plasmodium falciparum diagnosed in health centres and villages was initiated to develop a detailed P. falciparum risk map with the aim to identify priority areas for malaria control, estimate population at risk, and guide resource allocation in the Lao People's Democratic Republic. METHODS: Plasmodium falciparum incidence data were collected from point-referenced villages and health centres for the period 2006-2008 during a country-wide survey between December 2008 and January 2009. Using the highest recorded annual rate, continuous surfaces of P. falciparum incidence were produced by the inverse distance weighted interpolation technique. RESULTS: Incidence rates were obtained from 3,876 villages and 685 health centres. The risk map shows that P. falciparum is highly heterogeneous in the northern and central regions of the country with large areas of no transmission. In the southern part, transmission is pervasive and the risk of P. falciparum is high. It was estimated that 3.4 million people (60% of the population) live at risk of malaria. CONCLUSIONS: This paper presents the first comprehensive malaria risk map of the Lao People's Democratic Republic based entirely on empirical data. The estimated population at risk is substantially lower than previous estimates, reflecting the presence of vast areas with focal or no malaria transmission identified in this study. These findings provide important guidance for malaria control interventions in the Lao People's Democratic Republic, and underline the need for detailed data on malaria to accurately predict risk in countries with heterogeneous transmission.Malaria Journal 02/2010; 9(1):59. · 3.19 Impact Factor -
Article: Is staying overnight in a farming hut a risk factor for malaria infection in a setting with insecticide-treated bed nets in rural Laos?
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ABSTRACT: Overnight stays in farming huts are known to pose a risk of malaria infection. However, studies reporting the risk were conducted in the settings of poor net coverage. This study sought to assess whether an overnight stay in a farming hut is associated with an increased risk of malaria infection if insecticide-treated bed nets (ITNs) are properly used. A pair of cross-sectional surveys was carried out in the Lamarm district of Sekong province, Laos, in March (dry season) and August (rainy season) in 2008. Questionnaire-based interviews and blood examinations were conducted with farmers and their household members from three randomly selected villages in March (127 households, 891 people) and August (128 households, 919 people). Logistic regression analysis, adjusted for potential confounding factors, was used to assess the association between malaria infection status and frequency of overnight stays for the two weeks prior to the study in both the seasons. In March, 13.7% of participants reported staying overnight in a farming hut at least once in the previous two weeks. The percentage increased to 74.6% in August. Not only adults but also young children stayed overnight as often as adults. The use of an ITN the preceding night was common both in farming huts (66.3% in March, 95.2% in August), and in main residences (85.8% in March, 92.5% in August). Logistic regression analysis showed no statistical association between malaria infection status and frequency of overnight stays in farming huts in either study period. However, people sharing one family type net with five people or more were significantly more likely to have malaria than those sharing a net with up to two people in the dry season. This study showed that staying overnight in farming huts was not associated with an increased risk of malaria infection in the setting where ITNs were widely used in farming huts. It suggests that malaria infection during overnight stays in farming huts might be preventable if ITNs are properly used in rural Laos.Malaria Journal 01/2010; 9:372. · 3.19 Impact Factor -
Article: Geographic information system (GIS) maps and malaria control monitoring: intervention coverage and health outcome in distal villages of Khammouane province, Laos.
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ABSTRACT: Insecticide-treated nets (ITNs) are a key intervention to control malaria. The intervention coverage varies as a consequence of geographical accessibility to remote villages and limitations of financial and human resources for the intervention. People's adherence to the intervention, i.e., proper use of ITNs, also affects malaria health outcome. The study objective is to explore the impact of the intervention coverage and people's adherence to the intervention on malaria health outcome among targeted villages in various geographic locations. Geographic information system (GIS) maps were developed using the data collected in an active case detection survey in Khammouane province, Laos. The survey was conducted using rapid diagnostic tests (RDTs) and a structured questionnaire at 23 sites in the province from June to July, the rainy season, in 2005. A total of 1,711 villagers from 403 households participated in the survey. As indicated on the GIS maps, villages with malaria cases, lower intervention coverage, and lower adherence were identified. Although no malaria case was detected in most villages with the best access to the district center, several cases were detected in the distal villages, where the intervention coverage and adherence to the intervention remained relatively lower. Based on the data and maps, it was demonstrated that malaria remained unevenly distributed within districts. Balancing the intervention coverage in the distal villages with the overall coverage and continued promotion of the proper use of ITNs are necessary for a further reduction of malaria cases in the province.Malaria Journal 09/2009; 8:217. · 3.19 Impact Factor -
Article: Public and private sector treatment of malaria in Lao PDR.
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ABSTRACT: This study aimed to examine the care-seeking choices for treatment of a febrile illness compatible with malaria in the public and private sectors in Lao PDR. We conducted interviews with 745 heads of household in 14 villages in the Sekong province, using a structured-questionnaire. We asked each about who the care-providers were for febrile illness episodes affecting their household members during the past year. If patients used more than one care-provider for a single episode over a period of time, we identified patterns of the care-sequences for the initial and subsequent care choices. Then, we analyzed the relationship between the initial care choices and secondary care choices for care-providers by Chi-square test, categorizing care-providers into public (hospital, health centre, and village health volunteer) and private care-providers (private pharmacy, informal retailer, faith healing and herbs). As a result, we found that 624 patients sought care at least once, 255 (40.9%) twice, and 66 (10.6%) three times or more during a single episode. Of 138 patients who started with a public care-provider and then sought a secondary care, 71 (51.4%) switched to a private care-provider. In contrast, of 117 patients who started with a private care-provider and then sought a secondary care, 82 (70.1%) switched to a public care-provider (p<0.001). In conclusion, although most patients who failed being treated by a private care-provider switched to a public one, some exclusively relied on care within the private sector. An intervention is necessary to make the private sector an integral component of malaria treatment in Lao PDR.Acta tropica 09/2009; 112(3):283-7. · 2.22 Impact Factor -
Article: A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR - implications for therapeutic failure and drug resistance.
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ABSTRACT: Counterfeit oral artesunate has been a major public health problem in mainland SE Asia, impeding malaria control. A countrywide stratified random survey was performed to determine the availability and quality of oral artesunate in pharmacies and outlets (shops selling medicines) in the Lao PDR (Laos). In 2003, 'mystery' shoppers were asked to buy artesunate tablets from 180 outlets in 12 of the 18 Lao provinces. Outlets were selected using stratified random sampling by investigators not involved in sampling. Samples were analysed for packaging characteristics, by the Fast Red Dye test, high-performance liquid chromatography (HPLC), mass spectrometry (MS), X-ray diffractometry and pollen analysis. Of 180 outlets sampled, 25 (13.9%) sold oral artesunate. Outlets selling artesunate were more commonly found in the more malarious southern Laos. Of the 25 outlets, 22 (88%; 95%CI 68-97%) sold counterfeit artesunate, as defined by packaging and chemistry. No artesunate was detected in the counterfeits by any of the chemical analysis techniques and analysis of the packaging demonstrated seven different counterfeit types. There was complete agreement between the Fast Red dye test, HPLC and MS analysis. A wide variety of wrong active ingredients were found by MS. Of great concern, 4/27 (14.8%) fakes contained detectable amounts of artemisinin (0.26-115.7 mg/tablet). This random survey confirms results from previous convenience surveys that counterfeit artesunate is a severe public health problem. The presence of artemisinin in counterfeits may encourage malaria resistance to artemisinin derivatives. With increasing accessibility of artemisinin-derivative combination therapy (ACT) in Laos, the removal of artesunate monotherapy from pharmacies may be an effective intervention.Malaria Journal 08/2009; 8:172. · 3.19 Impact Factor -
Article: Monitoring malaria control in Khammouane province, Laos: an active case detection survey of Plasmodium falciparum malaria using the Paracheck rapid diagnostic test.
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ABSTRACT: In Khammouane province, Laos, over 5000 slide-positive malaria cases were reported at local health facilities in 1997. To combat the spread of malaria, insecticide-treated nets (ITNs) and community health education were provided to the people in this province by the Lao Ministry of Health and the Japan International Cooperation Agency. In order to document the current malaria situation, an active case detection (ACD) survey using rapid diagnostic tests was conducted at 23 sites from June to July, the rainy season, in 2005. A total of 1711 villagers from 403 households participated in the survey. The proportion of positive cases was 0.7% (12/1711) with a range in each village of 0-8.2%. The low infection rate observed in this ACD survey was consistent with the decrease in the number of slide-positive malaria cases at local health facilities (from over 5000 cases to 536 cases), indicating the substantial progress made in malaria control. Although the reduction of malaria cases can be attributed to multiple factors, continued promotion of the proper use of ITNs as well as community-based testing and treatment services, especially in remote areas, may lead to a further reduction of malaria cases in the province.Transactions of the Royal Society of Tropical Medicine and Hygiene 09/2008; 102(8):743-50. · 2.16 Impact Factor -
Article: Combined molecular and clinical assessment of Plasmodium falciparum antimalarial drug resistance in the Lao People's Democratic Republic (Laos).
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ABSTRACT: Molecular markers provide a rapid and relatively inexpensive approach for assessing antimalarial drug susceptibility. We collected 884 Plasmodium falciparum-infected blood samples from 17 Lao provinces. Each sample was genotyped for 11 codons in the chloroquine resistance transporter (pfcrt), dihydrofolate reductase (pfdhfr), and dihydropteroate synthase (pfdhps) genes. The samples included 227 collected from patients recruited to clinical trials. The pfcrt K76T mutation was an excellent predictor of treatment failure for both chloroquine and chloroquine plus sulfadoxine-pyrimethamine, and mutations in both pfdhfr and pfdhps were predictive of sulfadoxine-pyrimethamine treatment failure. In multivariate analysis, the presence of the pfdhfr triple mutation (51 + 59 + 108) was strongly and independently correlated with sulfadoxine-pyrimethamine failure (odds ratio = 9.1, 95% confidence interval = 1.4-60.2, P = 0.017). Considerable geographic heterogeneity in allele frequencies occurred at all three loci with lower frequencies of mutant alleles in southern than in northern Laos. These findings suggest that chloroquine and sulfadoxine-pyrimethamine are no longer viable therapy in this country.The American journal of tropical medicine and hygiene 08/2007; 77(1):36-43. · 2.59 Impact Factor -
Article: Diagnosis and management of malaria by rural community health providers in the Lao People's Democratic Republic (Laos).
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ABSTRACT: We assessed the knowledge of malaria diagnosis and management by community health providers in rural Vientiane and Savannakhet Provinces, Lao PDR. Sixty health providers (17 pharmacy owners/drug sellers and 43 village health volunteers) were interviewed. All diagnosed malaria using symptoms and signs only; 14% were aware of >2 criteria for the diagnosis of severe malaria. Although chloroquine and quinine, the then recommended Lao national policy for uncomplicated malaria treatment, were the most common antimalarials prescribed - 65% gave incorrect doses and 70% did not know the side effects. Although not recommended by the then national policy, 27% of the health providers used combinations of antimalarials as they considered monotherapy ineffective. This study strongly suggests that further training of Lao rural health providers in malaria diagnosis and management is needed to improve the quality of health services in areas remote from district hospitals.Tropical Medicine & International Health 04/2007; 12(4):540-6. · 2.80 Impact Factor -
Article: In vitro antimalarial drug susceptibility and pfcrt mutation among fresh Plasmodium falciparum isolates from the Lao PDR (Laos).
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ABSTRACT: Recent drug trials in Laos have shown high levels of Plasmodium falciparum resistance to chloroquine, but there are no published data on in vitro antimalarial drug susceptibility. We used the double-site enzyme-linked pLDH immunodetection (DELI) assay to estimate the in vitro antimalarial drug susceptibility of 108 fresh P. falciparum isolates from southern Laos. The geometric mean (95% confidence interval) 50% inhibitory concentration values (nmol/L) were 152.4 (123.8-187.6) for chloroquine, 679.8 (533.8-863.0) for quinine, 45.9 (37.9-55.7) for mefloquine, 5.0 (4.4-6.4) for artesunate, 6.3 (4.5-8.9) for dihydroartemisinin, and 59.1 (46.4-75.3) for lumefantrine. The proportion of isolates defined as resistant were 65%, 40%, and 8% for chloroquine, quinine, and mefloquine, respectively. Of 53 isolates genotyped for the pfcrt T76K chloroquine-resistance mutation, 48 (91%) were mutants. P. falciparum in Laos is multi-drug resistant; antimalarial immunity resulting from the use of ineffective chloroquine before 2005 probably contributes significantly to the therapeutic responses in clinical trials.The American journal of tropical medicine and hygiene 03/2007; 76(2):245-50. · 2.59 Impact Factor -
Article: Thiamin deficiency and uncomplicated falciparum malaria in Laos.
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ABSTRACT: Thiamin deficiency complicates severe Plasmodium falciparum malaria in Thailand and may contribute to acidosis. We therefore estimated the frequency of biochemical thiamin deficiency in patients presenting with uncomplicated falciparum malaria in southern Laos. Red cell transketolase activation coefficients (alpha) were measured in 310 patients presenting with uncomplicated falciparum malaria and 42 days after starting treatment. Twelve per cent of patients had biochemical evidence of severe deficiency (alpha values >1.31) at presentation, declining to 3% 42 days later. Thiamin deficiency was common in Lao patients admitted with uncomplicated P. falciparum infection and was reduced following treatment of malaria and multivitamin supplementation. The role of this preventable and treatable disorder in malaria and other acute infections, and the incidence of beriberi in rural Laos, needs further investigation.Tropical Medicine & International Health 03/2007; 12(3):363-9. · 2.80 Impact Factor -
Article: Thiamin deficiency and uncomplicated falciparum malaria in Laos
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ABSTRACT: Objective Thiamin deficiency complicates severe Plasmodium falciparum malaria in Thailand and may contribute to acidosis. We therefore estimated the frequency of biochemical thiamin deficiency in patients presenting with uncomplicated falciparum malaria in southern Laos.Methods Red cell transketolase activation coefficients () were measured in 310 patients presenting with uncomplicated falciparum malaria and 42 days after starting treatment.Results Twelve per cent of patients had biochemical evidence of severe deficiency ( values >1.31) at presentation, declining to 3% 42 days later.Conclusion Thiamin deficiency was common in Lao patients admitted with uncomplicated P. falciparum infection and was reduced following treatment of malaria and multivitamin supplementation. The role of this preventable and treatable disorder in malaria and other acute infections, and the incidence of beriberi in rural Laos, needs further investigation.Objectif La déficience en thiamine complique la malaria sévère àPlasmodium falciparum en Thaïlande et peut contribuer à de l'acidose. Nous avons estimé la fréquence de la déficience biochimique en thiamine chez des patients présentant une malaria falciparum non compliquée dans le sud du Laos.Méthode Les coefficients ‘‘ de l'activation de la transcétolase dans les globules rouges ont été mesurés chez 310 patients avec une malaria falciparum non compliquée à leur présentation et à 42 jours après instauration du traitement.Résultats 12% des patients avaient une évidence biochimique de déficience sévère (valeurs de > 1,31) à la présentation. Ce taux diminuait à 3% lorsque mesuré 42 jours plus tard.Conclusion La déficience en thiamine était commune chez les patients Laotiens admis avec une infection non compliquée àP. falciparum. Cette déficience a été réduite après traitement de la malaria et supplémentation en multivitamines. Le rôle de cette déficience évitable et traitable dans la malaria et dans d'autres infections aiguës, ainsi que l'incidence du béribéri chez les Laotiens ruraux, nécessite des recherches supplémentaires.Objetivo La deficiencia de tiamina complica la malaria severa por Plasmodium falciparum en Tailandia y puede contribuir a la acidosis. El objetivo de este estudio fue estimar la frecuencia de deficiencia bioquímica de tiamina en pacientes que presentan malaria no complicada por falciparum en el sur de Laos.Método Los coeficientes () de activación de la transquetolasa de los eritrocitos fueron medidos en 310 pacientes al momento de presentarse con malaria no complicada por falciparum, así como 42 días después de comenzar tratamiento.Resultados Un doce por ciento de los pacientes presentaban evidencia bioquímica de deficiencia severa (valores > 1.31) al momento de presentarse con malaria. Este valor disminuía a un 3% 42 días después.Conclusión La deficiencia de tiamina era común en pacientes de Laos admitidos con malaria no complicada por P.falciparum, y se redujo después del tratamiento de la malaria y de la suplementación con un complejo multivitamínico. Sería conveniente investigar más a fondo el papel de este desorden prevenible y tratable, en malaria y otras infecciones agudas, y la incidencia de beriberi en Laos rural,.Tropical Medicine & International Health 02/2007; 12(3):363 - 369. · 2.80 Impact Factor -
Article: Minimising human error in malaria rapid diagnosis: clarity of written instructions and health worker performance.
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ABSTRACT: The usefulness of rapid diagnostic tests (RDT) in malaria case management depends on the accuracy of the diagnoses they provide. Despite their apparent simplicity, previous studies indicate that RDT accuracy is highly user-dependent. As malaria RDTs will frequently be used in remote areas with little supervision or support, minimising mistakes is crucial. This paper describes the development of new instructions (job aids) to improve health worker performance, based on observations of common errors made by remote health workers and villagers in preparing and interpreting RDTs, in the Philippines and Laos. Initial preparation using the instructions provided by the manufacturer was poor, but improved significantly with the job aids (e.g. correct use both of the dipstick and cassette increased in the Philippines by 17%). However, mistakes in preparation remained commonplace, especially for dipstick RDTs, as did mistakes in interpretation of results. A short orientation on correct use and interpretation further improved accuracy, from 70% to 80%. The results indicate that apparently simple diagnostic tests can be poorly performed and interpreted, but provision of clear, simple instructions can reduce these errors. Preparation of appropriate instructions and training as well as monitoring of user behaviour are an essential part of rapid test implementation.Transactions of the Royal Society of Tropical Medicine and Hygiene 02/2007; 101(1):9-18. · 2.16 Impact Factor -
Article: Modern medicine and indigenous health beliefs: malaria control alongside "Sadsana-phee" (animist belief system) in Lao PDR.
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ABSTRACT: The major religion in Lao PDR is Buddhism, but many ethnic groups in rural Lao PDR hold an animist belief system called "Sadsana-pee". At the same time, the Bourapar District study site in Khammouane Province, Lao PDR is at high risk of malaria infection. Due to their belief in traditional ways of healing, the promotion of malaria prevention and treatment with modern medicine was not always welcomed by the villagers. Based on the results of questionnaire interviews with 240 heads of households from February to March of 2003, the effect of local beliefs on malaria control activities was discussed. Despite widely available western medicine and widely conducted health education, some people still believe that evil spirits cause malaria and rely on traditional medicine and/or religious ceremonies for treatment. Based on our findings, we recommend that future education and malaria control programs be revised and made sensitive to those people holding indigenous beliefs.The Southeast Asian journal of tropical medicine and public health 08/2006; 37(4):622-9. · 0.60 Impact Factor -
Article: Falciparum malaria in the north of Laos: the occurrence and implications of the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene haplotype SVMNT.
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ABSTRACT: The Pfcrt-gene encodes a transmembrane protein located in the Plasmodium falciparum digestive vacuole. Chloroquine resistant (CQR) strains of African and Southeast Asian origin carry the Pfcrt-haplotype (c72-76) CVIET, whereas most South American and Papua New Guinean CQR stains carry the SVMNT haplotype. Eighty-eight samples from an area with reported in vivo Chloroquine and in vitro Amodiaquine-resistance were screened for the K76T mutation and their Pfcrt-haplotype (c72-76) using a new SSOP-ELISA. Hundred percent of the analysed samples showed the K76T mutation which is highly associated with in vivo drug failure. This very high rate of a CQR-marker is alarming in an area were CQ is still used as first line drug. The distribution of the three main Pfcrt-haplotypes was as follows: 68% CVIET, 31% SVMNT, 0% CVMNT. These data show, for the first time, the South American/PNG -haplotype (SVMNT) on mainland Southeast Asia. SVMNT-haplotype and others might be associated with a decreased efficacy of Amodiaquine and could therefore be potential markers for of amodiaquine resistance (AQR). If there is a correlation between AQR and the SVMNT-haplotype as suggested, 31% prevalence of a potential resistance marker is cause for concern.Tropical Medicine & International Health 01/2006; 10(12):1267-70. · 2.80 Impact Factor
Top co-authors
Top Journals
Institutions
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2003–2011
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University of Ryukyus
- Faculty of Medicine
Okinawa, Okinawa-ken, Japan
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2007
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Mahidol University
- Faculty of Tropical Medicine
Bangkok, Bangkok, Thailand -
National Institute of Malariology, Parasitology and Entomology (NIMPE)
Hà Nội, Thu Do Ha Noi, Vietnam
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2004
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Charité Universitätsmedizin Berlin
Berlin, Land Berlin, Germany
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2003–2004
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National University of Laos
Vientiane, Kampheng Nakhon Viangchan, Laos
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