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This study was undertaken to ascertain the extent of polymorphism in the C-terminal region of Plasmodium falciparum merozoite surface protein (MSP-1) from 119 malaria patients in Tak Province on the western border of Thailand, who were admitted to the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. P. falciparum infection was confirmed by microscopic examination of peripheral blood smears. Clinical manifestations were categorized into 2 groups: uncomplicated (94 cases) and complicated/severe (25 cases). A 1,040 basepair fragment of P. falciparum MSP-1 gene was compared with MSP-1 of reference strains retrieved from GenBank. The consensus sequences of MSP-1 block 16 showed it belonged to MAD20 genotype, which is the major allele of falciparum malaria from the western border of Thailand. MSP-1 block 16 amino acid fragment could be separated into 2 groups: similar and dissimilar to reference sequence. Four variations in MSP-1 block 16 were -1494K, D1510G, D1556N, and K1696I. MSP-1 block 16 diversity is not significantly associated with clinical manifestation although MAD 20 genotype is the predominant genotype in this area. The genetic data of MSP1 gene of faciparum malaria isolated from western Thai border contribute to the existing genetic database of Thai P. falciparum strain.

We report a rare case of human thelaziasis. A 31-year-old man from Nakhon Pathom, Thailand presented to the hospital with a foreign body sensation in and excessive lacrimation from the right eye for one week. His visual acuity was normal. He gave a history of a fly flying around his face; he then rubbed it against his right eye. Five adult worms were collected from the right eye. Two were removed by the patients and three were removed on the ward, using a small cotton swab, from the conjunctival sac. All five worms were identified morphologically as Thelazia callipaeda. The patient became free of symptoms after the fifth worm was removed.

Objective: To determine the frequency of malaria parasite detection from the buffy coat blood films by using capillary tube in falciparum malaria patients with negative conventional thick films., Methods: Thirty six uncomplicated falciparum malaria patients confirmed by conventional thick and thin films were included in the study. The patients were treated with artemisinin combination therapy at Hospital for Tropical Diseases, Bangkok, Thailand for 28 day. Fingerpricks for conventional blood films were conducted every 6 hours until negative parasitemia, then daily fingerpricks for parasite checks were conducted until the patients were discharged from hospital. Blood samples were also concurrently collected in 3 heparinized capillary tubes at the same time of fingerpricks for conventional blood films when the prior parasitemia was negative on thin films and parasitemia was lower than 50 parasites/200 white blood cells by thick film. The first negative conventional thick films were compared with buffy coat thick films for parasite identification., Results: Out of 36 patients with thick films showing negative for asexual forms of parasites, buffy coat films could detect remaining 10 patients (27.8%) with asexual forms of Plasmodium falciparum., Conclusions: The study shows that buffy coat thick films are useful and can detect malarial parasites in 27.8% of patients whose conventional thick films show negative parasitemia.

Thailand is not an endemic area for leishmaniasis. Several cases of autochthonous visceral leishmaniasis have been reported from Thailand but cutaneous leishmaniasis has never been reported. We reported a three-year-old girl who presented with a chronic ulcer on her cheek which proved to be cutaneous leishmaniasis. The diagnosis was made by finding amastigotes on skin biopsy; the patient had a therapeutic response to itraconazole.

The NOW® Malaria Test, an immunochromatographic test (ICT), was evaluated to determine its ability to quantitatively detect malaria parasites using 100 blood samples from Thailand, including 50 Plasmodium falciparum (Pf) infections and 50 P. vivax (Pv) infections. Intensities of the thickness of the visible bands of the positive ICT were compared with the parasite densities. In cases of Pf infection, the intensities of both HRP-2 bands (T1 bands: Pf specific bands) and aldolase bands (T2 bands: pan-Plasmodium bands) correlated with the parasite densities. The intensities of T2 bands in Pf positive samples showed better correlation with the parasite densities than the T1 bands. In the cases of Pv infection, the intensities of T2 bands were also well correlated with parasite density. These results suggest that the ICT is useful not only for rapid detection of malaria parasites but also for estimating parasite density.

Randomized trials have confirmed the efficacy and safety of artemether-lumefantrine (AL) for treatment of uncomplicated Plasmodium falciparum malaria. Data from seven studies supported by Novartis (1996-2007), including 647 adults (> 16 years of age, 83.3% completed the study) and 1,332 children (≤ 16 years of age, 89.3% completed the study) with microscopically confirmed uncomplicated P. falciparum malaria and treated with the recommended regimen of AL, were pooled. The 28-day polymerase chain reaction-corrected parasitologic cure rate (primary efficacy endpoint) was 97.1% (495 of 510) in adults and 97.3% (792 of 814) in children (evaluable population). Gametocytemia prevalence after day was 4.2% (23 of 554) in adults and 0.9% (8 of 846) in children. No noteworthy safety signals were observed. Serious adverse events occurred in 1.4% of the adults and 1.3% of the children. This study is the largest data set to date assessing AL therapy for treatment of acute uncomplicated P. falciparum malaria. Artemether-lumefantrine showed high cure rates and rapid resolution of parasitemia, fever, and gametocytemia in adults and children, and showed an excellent safety and tolerability profile.

To identify factors associated with acute renal failure among patients with severe falciparum malaria (MARF), we studied 189 severe malaria patients admitted to the Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, in Bangkok, Thailand. Among these, 63 had MARF, and 126 did not. Baseline clinical demographics and laboratory variables were evaluated with univariate analysis. Logistic regression was used to ascertain adjusted odds ratios. By univariate analysis, factors associated with MARF included male gender, fever duration > 4 days, patients who lived in a non-endemic area prior to malaria infection, body mass index > 18.5 kg/m(2), oliguria, abdominal pain, impaired consciousness, jaundice, anemia, liver enlargement, total white blood cell count > 10x10(9)/1, total bilirubin > 3 mg/dl, aspartate aminotransferase > 120 U/l, alanine aminotransferase > 120 U/l, albumin < 3 g/dl, fever clearance time >72 hours, and parasite clearance time > 72 hours. A hemoglobin > 10 g/dl, patients living in a malaria endemic area, non-oliguria on the day of admission, and splenomegaly were negatively associated with MARF. After multivariate logistic regression, oliguria during the first 24 hours of admission and a history of living in a nonendemic area prior to malarial infection were factors associated with MARF. We conclude the most significant factors associated with MARF were oliguria on the day of admission and living in a non-endemic area prior to malaria infection.

This study aimed to determine the knowledge of diabetes, practices of self-management (SM), and potential factors influencing patient knowledge and practices of self-management among individuals with type 2 diabetes in urban Anhui Province, China. A cross-sectional study was conducted between October and November, 2009. Three hundred sixty-five subjects with type 2 diabetes were randomly selected from three urban communities in three seperate cities. An interview was conducted to determine subject knowledge regarding diabetes, practices of self-management, and potential factors influencing this knowledge and these practices of self-management. Fewer than half of subjects (45.6%) had a basic knowledge of diabetes and 49.7% practiced adequate self-management. Significant associations were found between subject knowledge of diabetes and their education level (OR 2.096, 95% CI 1.578-2.784) and the length of disease (OR 1.307, 95% CI 1.016-1.681). Those with good self-management were influenced by greater knowledge, (OR 2.057,95% CI 1.228-3.445), strong self-efficacy in diabetes self-management (OR 1.899, CI 1.253-2.878), and household income (OR 0.537, 95% CI 0.419-0.689). Factors found by univariate analysis regarding self-management included: glucose monitoring was influenced by perception of social support (p = 0.006), adherence to medication was influenced by attitude toward self-management (p < 0.001), physical activity was influenced by knowledge (p < 0.01), attitude (p < 0.01), self-efficacy (p < 0.01), and social support (p < 0.01). However, there were no factors significantly related to healthy dietary practices. Our findings show that best performance in self-management is achieved when those with type 2 diabetes have a high degree of knowledge of diabetes, positive attitudes toward diabetes, strong self-efficacy for self-management and perceptions of good social support.

This study was carried out from April 2005 to June 2006 to evaluate the recurrence of P. vivax malaria infection in relation to drug compliance along the Thai-Myanmar border in Ratchaburi, Thailand. Ninety-two patients with vivax malaria were sequentially assigned to 2 groups. Both groups received a standard dose of chloroquine (total dose = 2.5 g) for 3 days and primaquine (total dose = 210 mg) for 14 days. The experimental group received a full course of treatment using daily directly observed therapy (DOT) while subjects in the control group were given the medication with necessary instructions to take as self-administered therapy (SAT). Patients were followed up for 3 months on Days 14, 21, 28, 60 and 90. Five of 46 patients from the SAT group had recurrence of malaria on Days 21, 44, 60, 72 and 87. Recurrence was not observed among patients in the DOT group. Survival analysis also showed significant differences between the SAT and DOT groups (p <0.05). The study suggests patient compliance with the 14-day primaquine treatment with DOT improve the outcome of .vivax malaria treatment.

Background: The efficacy of anti-malarial drugs is determined by the level of parasite susceptibility, anti-malarial drug bioavailability and pharmacokinetics, and host factors including immunity. Host immunity improves the in vivo therapeutic efficacy of anti-malarial drugs, but the mechanism and magnitude of this effect has not been characterized. This study characterized the effects of 'immune' plasma to Plasmodium falciparumon the in vitro susceptibility of P. falciparum to anti-malarial drugs., Methods: Titres of antibodies against blood stage antigens (mainly the ring-infected erythrocyte surface antigen [RESA]) were measured in plasma samples obtained from Thai patients with acute falciparum malaria. 'Immune' plasma was selected and its effects on in vitro parasite growth and multiplication of the Thai P. falciparum laboratory strain TM267 were assessed by light microscopy. The in vitro susceptibility to quinine and artesunate was then determined in the presence and absence of 'immune' plasma using the 3H-hypoxanthine uptake inhibition method. Drug susceptibility was expressed as the concentrations causing 50% and 90% inhibition (IC50 and IC90), of 3H-hypoxanthine uptake., Results: Incubation with 'immune' plasma reduced parasite maturation and decreased parasite multiplication in a dose dependent manner. 3H-hypoxanthine incorporation after incubation with 'immune' plasma was decreased significantly compared to controls (median [range]; 181.5 [0 to 3,269] cpm versus 1,222.5 [388 to 5,932] cpm) (p= 0.001). As a result 'immune' plasma reduced apparent susceptibility to quinine substantially; median (range) IC50 6.4 (0.5 to 23.8) ng/ml versus 221.5 (174.4 to 250.4) ng/ml (p = 0.02), and also had a borderline effect on artesunate susceptibility; IC50 0.2 (0.02 to 0.3) ng/ml versus 0.8 (0.2 to 2.3) ng/ml (p = 0.08). Effects were greatest at low concentrations, changing the shape of the concentration-effect relationship. IC90 values were not significantly affected; median (range) IC90 448.0 (65 to > 500) ng/ml versus 368.8 (261 to 501) ng/ml for quinine (p > 0.05) and 17.0 (0.1 to 29.5) ng/ml versus 7.6 (2.3 to 19.5) ng/ml for artesunate (p = 0.4)., Conclusions: 'Immune' plasma containing anti-malarial antibodies inhibits parasite development and multiplication and increases apparent in vitro anti-malarial drug susceptibility of P. falciparum. The IC90 was much less affected than the IC50 measurement.

Artemesinin-combination therapies (ACTs) for falciparum malaria reduce gametocyte carriage, and therefore reduce transmission. Artemisinin derivatives act only against young gametocytes, but primaquine acts against mature gametocytes (which are usually present in the circulation at the time the patient presents for treatment). Both artemisnin derivatives and primaquine have short half-lives (less than 1 hour and 8 hours, respectively). Therefore, asexual parasites and young gametocytes may remain after completing ACT. Single dose of primaquine (0.5-0.75 mg base/kg) at the end of ACT can kill only mature gametocytes (if present) but cannot kill young gametocytes (if present). Remaining asexual forms and sequestered young gametocytes remaining after completion of ACT may develop into mature gametocytes 7-15 days later. Some patients have the first appearance of gametocytemia 4-8/day after completion of ACT. Thus, additional doses of primaquine (0.5-0.75 mg base/kg) given 15-18 days after or concurrently with 3 day-ACT respectively or given 15-22 days after or concurrently with 7 day-ACT respectively may be beneficial in killing the remaining mature gametocytes and thus contribute to interruption of P. falciparum gametocyte transmission more affectively than giving only a single dose of primaquine just after completing ACT.

Background: Drug-resistant Plasmodium falciparum malaria necessitates development of novel drugs for treatment.The present study assessed the efficacy and safety of 3 dose levels of arterolane (RBx 11160), a synthetic trioxolane, for treatment of acute uncomplicated falciparum malaria., Methods: In this randomized, double-blind, multicenter, parallel-group, dose-finding, phase II trial, 230 patients from 4 centers in Thailand, India, and Tanzania (mainland and Zanzibar) received either 50 mg (n=78), 100mg (n=76), or 200 mg (n=76) of arterolane once daily for 7 days. Patients (aged 13-65 years) with asexual parasite density of 1000-100,000 parasites/microL were included and were followed up for 28 days. The median time to 90% parasite clearance (PC90) was evaluated., Results: The median PC90 was longer in the group receiving the 50-mg dose (19.4 h), compared with the groups receiving the 100-mg dose (12.8 h) and 200-mg dose (12.6 h) (P < .01). The polymerase chain reaction-corrected adequate clinical and parasitological responses on day 28 were 63%, 71%, and 72% for the groups receiving the 50-mg, 100-mg, and 200-mg doses, respectively, by intention-to-treat analysis (odds ratio, 1.55; 95%confidence interval, 0.78-3.06, for comparison of the 200-mg and 50-mg dose groups). Treatment was generally well tolerated. No patient died or experienced any serious adverse event. Mild complaints were reported in <10%of the patients and were similar in the 3 groups. Biochemistry and hematological analyses did not show any signof drug toxicity in any patient., Conclusion: Arterolane at daily doses of 100 and 200 mg is a rapidly acting, effective, and safe synthetic antimalarial drug, which may potentially represent an alternative to artemisinin derivatives in antimalarial combination therapy., Trial Registration: ClinicalTrials.gov identifier NCT00362050.

This study investigated alterations in platelet counts pre- and post-treatment with artemisinin derivatives in uncomplicated and severe falciparum malaria. Serial platelet counts were taken over 4 weeks for 110 uncomplicated and 110 severe falciparum malaria patients admitted to the Hospital for Tropical Diseases during 2005-2008. On admission, prior to treatment, thrombocytopenia was found in 73.6% of uncomplicated falciparum malaria patients and 90.9% of severe falciparum malaria cases. Platelet levels significantly lower in severe malaria cases. Although initial platelet counts were lower than normal in both study groups, they slowly increased significantly over time, and approached normal levels by several weeks post-treatment. No bleeding was evident during treatment, and none of the patients required a platelet transfusion. Platelet transfusions are not required for malaria patients with thrombocytopenia who have no bleeding.

Because some febrile patients are unable to swallow or retain oral antipyretic drugs, we carried out a double-blind, placebo-controlled trial in which intravenous ibuprofen (IV-ibuprofen) was given to adults hospitalized with fever associated with acute uncomplicated falciparum malaria treated with oral artesunate plus mefloquine. Thirty patients received IV-ibuprofen 400 mg and 30 received placebo every 6 hours for 72 hours. Reduction in the area above 37.0 degrees C versus time curve was significantly greater for IV-ibuprofen than for placebo during the first 72 hours after first administration. No patients developed severe malaria; parasite clearance was delayed in the patients whose fevers were controlled by IV-ibuprofen (median 37.3 hours versus 23.7 hours in the placebo group [P = 0.0024]). This difference did not appear to be clinically important Adverse events, none considered severe, occurred equally in both groups. IV-ibuprofen was effective and well tolerated in reducing fever in febrile inpatients with malaria.

Mixed infections of Plasmodium falciparum and Plasmodium vivax is high (approximately 30%) in some malaria hypoendemic areas where the patients present with P. falciparum malaria diagnosed by microscopy. Conventional treatment of P. falciparum with concurrent chloroquine and 14 days of primaquine for all falciparum malaria patients may be useful in areas where mixed falciparum and vivax infections are high and common and also with mild or moderate G6PD deficiency in the population even with or without subpatent vivax mixed infection. It will be possibly cost-effective to reduce subsequent vivax illness if the patients have mixed vivax infection. Further study to prove this hypothesis may be warranted.

Artemesinin-combination therapies (ACT) for falciparum malaria reduce gametocyte carriage, and therefore reduce transmission. Artemisinin derivatives will act against only young gametocytes whereas primaquine acts on mature gametocytes which are present usually in the circulation at the time when the patient presents for treatment. Both artemisinin derivatives and primaquine have short half-lives, less than 1 hr and 7 hr, respectively. Therefore, asexual parasites or young gametocytes remain after completed ACT. A single dose of primaquine (0.50-0.75 mg base/kg) at the end of ACT can kill only mature gametocytes but cannot kill young gametocytes (if present). Remaining asexual forms after completion of ACT course, e.g., artesunate-mefloquine for 3 days, may develop to mature gametocytes 7-15 days later. Thus, an additional dose of primaquine (0.50-0.75 mg base/kg) given 2 weeks after ACT completion may be beneficial for killing remaining mature gametocytes and contribute to more interruption of Plasmodium falciparum transmission than giving only 1 single dose of primaquine just after completing ACT.

Not all clinicians give vitamin K to severe malaria patients with systemic bleeding. Vitamin K injections may not be useful to stop bleeding in severe malaria patients with predominant hepatocellular jaundice. However, vitamin K may be justified in bleeding patients who have prolonged fasting of more than 3-7 days, underlying malnutrition, or predominant cholestatic jaundice. The decision to give vitamin K to severe malaria patients with systemic bleeding should be based on underlying diseases, type of jaundice, risk for vitamin K deficiency, and allergy to the drug.

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.

Background and Aims: Plasmodium falciparum (PF) infection can lead to severe complications. Ursodeoxycholic acid (UDCA) is increasingly used for the treatment of cholestatic liver diseases. The present study aims to determine the effects of combined UDCA and artesunate compared to placebo and artesunate on the improvement of liver tests in severe PF jaundiced patients., Methods: All severe PF jaundiced patients, aged > or = 15 years and diagnosed as having severe malaria according to WHO 2000 criteria, were enrolled. Patients with evidence of biliary obstruction, other cholestatic liver diseases and those who were pregnant were excluded. Patients were randomized to receive either oral UDCA or placebo for 2 weeks in additional to artesunate. All patients were admitted for at least 14 days to monitor the result of the treatment., Results: Seventy-four severe PF malaria patients with jaundice were enrolled. Both groups had similar demographic and laboratory tests, with the exception being more males in the UDCA group than in the placebo group (P = 0.04). The median of percentage change of total bilirubin and aminotransferase levels at the end of weeks 1, 2, 3 and 4 showed no difference between the two groups. Only the median of percentage change of alkaline phosphatase at the end of week one compared with the baseline values showed less increment in the UDCA group than in the placebo group (P = 0.04). No serious adverse events were seen during the 4 weeks of follow up., Conclusions: In severe PF malaria patients with jaundice, combined therapy with UDCA and artesunate is safe, but does not significantly improve liver tests compared to placebo and artesunate.

Plasmodium knowlesi morphologically resembles P. malariae; PCR assays are able to differentiate between the 2 species correctly. However, PCR is not available in many hospitals in P. knowlesi endemic areas, particularly in Southeast Asia. In places where PCR is not available, anti-malarial drugs for P. malariae or other non-P. falciparum or P. falciparum species are effective against P. knowlesi. Even with a wrong diagnosis of another malaria species by light microscopy instead of P. knowlesi, the antimalarial drugs given are still effective for treating P. knowlesi infection.

Background: Severe and cerebral malaria are associated with endothelial activation. Angiopoietin-1 (ANG-1) and angiopoietin-2 (ANG-2) are major regulators of endothelial activation and integrity. The aim of this study was to investigate the clinical utility of whole blood angiopoietin (ANG) levels as biomarkers of disease severity in Plasmodium falciparum malaria., Methods: The utility of whole blood ANG levels was examined in Thai patients to distinguish cerebral (CM; n = 87) and severe (non-cerebral) malaria (SM; n = 36) from uncomplicated malaria (UM; n = 70). Comparative statistics are reported using a non-parametric univariate analysis (Kruskal-Wallis test or Chi-squared test, as appropriate). Multivariate binary logistic regression was used to examine differences in whole blood protein levels between groups (UM, SM, CM), adjusting for differences due to ethnicity, age, parasitaemia and sex. Receiver operating characteristic curve analysis was used to assess the diagnostic accuracy of the ANGs in their ability to distinguish between UM, SM and CM. Cumulative organ injury scores were obtained for patients with severe disease based on the presence of acute renal failure, jaundice, severe anaemia, circulatory collapse or coma., Results: ANG-1 and ANG-2 were readily detectable in whole blood. Compared to UM there were significant decreases in ANG-1 (p < 0.001) and significant increases in ANG-2 (p < 0.001) levels and the ratio of ANG-2: ANG-1 (p < 0.001) observed in patients with SM and CM. This effect was independent of covariates (ethnicity, age, parasitaemia, sex). Further, there was a significant decrease in ANG-1 levels in patients with SM (non-cerebral) versus CM (p < 0.001). In participants with severe disease, ANG-2, but not ANG-1, levels correlated with cumulative organ injury scores; however, ANG-1 correlated with the presence of renal dysfunction and coma. Receiver operating characteristic curve analysis demonstrated that the level of ANG-1, the level of ANG-2 or the ratio of ANG-2: ANG-1 discriminated between individuals with UM and SM (area under the curve, p-value: ANG-2, 0.763, p < 0.001; ANG-1, 0.884, p < 0.001; Ratio, 0.857, p < 0.001) or UM and CM (area under the curve, p-value: ANG-2, 0.772, p < 0.001; ANG-1, 0.778, p < 0.001; Ratio, 0.820, p < 0.001)., Conclusions: These results suggest that whole blood ANG-1/2 levels are promising clinically informative biomarkers of disease severity in malarial syndromes.

Current World Health Organization (WHO) guidelines for the treatment of uncomplicated falciparum malaria recommend the use of artemisinin-based combination therapy (ACT). Artemether/lumefantrine is an ACT prequalified by the WHO for efficacy, safety and quality, approved by Swissmedic in December 2008 and recently approved by the USA FDA. Coartem is a fixed-dose combination of artemether and lumefantrine. Its two components have different modes of action that provide synergistic anti-malarial activity. It is indicated for the treatment of infants, children and adults with acute, uncomplicated infection due to Plasmodium falciparum or mixed infections including P. falciparum. A formulation with improved palatability has been developed especially for children (Coartem Dispersible), which rapidly disperses in a small amount of water for ease of administration. The efficacy of the six-dose regimen of artemether/lumefantrine has been confirmed in many different patient populations around the world, consistently achieving 28-day PCR (polymerase chain reaction)-corrected cure rates of >95% in the evaluable population, rapidly clearing parasitaemia and fever, and demonstrating a significant gametocidal effect, even in areas of widespread parasite resistance to other antimalarials.

Background: Despite the use of potent antimalarial drugs, the fatality rate associated with severe malaria remains high. Adjunctive therapies that target the immunopathological responses to infection may decrease mortality associated with severe malaria. We hypothesized that peroxisome proliferator-activated receptor gamma agonists (eg, rosiglitazone) would modulate the host's innate immune response to malaria and improve outcome., Methods: In a randomized, double-blind, placebo-controlled, phase I/II trial of treatment for malaria acquired in Thailand, we investigated the safety, tolerability, and efficacy of rosiglitazone use for parasite clearance and for reducing malaria-induced inflammation. Sequential patients with uncomplicated Plasmodium falciparum malaria were randomly assigned to 1 of 2 groups: 70 patients received rosiglitazone 4 mg twice daily for 4 days, and 70 patients received a placebo twice daily for 4 days. Both groups also received standard antimalarial therapy (ie, a fixed combination of 1000 mg of atovaquone per day for 3 days and 400 mg of proguanil per day for 3 days). Primary efficacy outcomes were 50% and 90% parasite clearance times (PCTs). Secondary outcomes were fever clearance time, levels of inflammatory mediators, blood glucose measurements, aminotransferase levels, admission to intensive care, and subjective tolerability of study drug., Results: For the 70 patients who received rosiglitazone, parasite clearance from peripheral blood was significantly enhanced, compared with the 70 patients who received a placebo (mean 50% PCT, 19.0 h vs. 24.6 h [p = .029]; mean 90% PCT, 30.9 h vs. 40.4 h [p = .004]). Also, the patients who received rosiglitazone had reduced inflammatory responses to infection, compared with the patients who received a placebo (ie, interleukin-6 levels at 24 h [p < .005] and at 48 h [p = .013] and monocyte chemoattractant protein-1 level at 48 h [p = .05]). There were no significant differences between the 2 groups with regard to safety and tolerability of treatment, and there were no admissions the intensive care unit or deaths., Conclusions: The use of rosiglitazone is a well-tolerated adjunct to standard therapy for nonsevere P. falciparum malaria. Treatment with rosiglitazone increased parasite clearance and decreased inflammatory biomarkers associated with adverse malaria outcomes., Trial Registration: ClinicalTrials.gov identifier NCT00149383 .

Most trials of antimalarials occur in areas in which reinfections are possible. For Plasmodium falciparum, reinfections are distinguished from recrudescences by polymerase chain reaction analysis of 3 polymorphic genes. However, the validity of this approach has never been rigorously tested. We tested for misclassification in 6 patients from clinical trials in Thailand and Cambodia who were classified as being reinfected by the standard polymerase chain reaction protocol. Using heteroduplex tracking assays and direct DNA sequencing, we found that 5 (83%) of 6 patients were misclassified. Misclassification in this manner overestimates the efficacy of antimalarials and delays the recognition of decreasing therapeutic efficacy, thus delaying potential changes in policy.

Malaria is a major cause of death in tropical and sub-tropical countries, killing each year over 1 million people globally; 90% of fatalities occur in African children. Although effective ways to manage malaria now exist, the number of malaria cases is still increasing, due to several factors. In this emergency situation, prompt and effective diagnostic methods are essential for the management and control of malaria. Traditional methods for diagnosing malaria remain problematic; therefore, new technologies have been developed and introduced to overcome the limitations. This review details the currently available diagnostic methods for malaria.

Using a range of laboratory-adapted and genetically modified Plasmodium falciparum parasite isolates, we investigated the interaction between dihydroartemisinin and piperaquine (PIP), the individual components of an artemisinin combination therapy currently under development, in addition to the role of known drug resistance genes in parasite susceptibility in vitro. All but one parasite line investigated displayed an interaction of dihydroartemisinin and PIP that was antagonistic, although the degree of antagonism was isolate dependent. In terms of resistance markers, the pfcrt haplotypes CVIET and SVMNT were positively associated with reduced sensitivity to PIP, with parasites carrying the South American CQR (SVMNT) allele being generally less sensitive than CVIET parasites. Parasites carrying the CQS (CVMNK) allele displayed a further increase in PIP sensitivity compared with CVIET and SVMNT parasites. Our data indicate that PIP sensitivity was not affected by pfmdr1 sequence status, despite positive correlations between the structurally related compound amodiaquine and pfmdr1 mutations in other studies. In contrast, neither the pfcrt nor pfmdr1 sequence status had any significant impact on susceptibility to dihydroartemisinin.

Background: Limited tools exist to identify which individuals infected with Plasmodium falciparum are at risk of developing serious complications such as cerebral malaria (CM). The objective of this study was to assess serum biomarkers that differentiate between CM and non-CM, with the long-term goal of developing a clinically informative prognostic test for severe malaria., Methodology/principal Findings: Based on the hypothesis that endothelial activation and blood-brain-barrier dysfunction contribute to CM pathogenesis, we examined the endothelial regulators, angiopoietin-1 (ANG-1) and angiopoietin-2 (ANG-2), in serum samples from P. falciparum-infected patients with uncomplicated malaria (UM) or CM, from two diverse populations--Thai adults and Ugandan children. Angiopoietin levels were compared to tumour necrosis factor (TNF). In both populations, ANG-1 levels were significantly decreased and ANG-2 levels were significantly increased in CM versus UM and healthy controls (p<0.001). TNF was significantly elevated in CM in the Thai adult population (p<0.001), but did not discriminate well between CM and UM in African children. Receiver operating characteristic curve analysis showed that ANG-1 and the ratio of ANG-2:ANG-1 accurately discriminated CM patients from UM in both populations. Applied as a diagnostic test, ANG-1 had a sensitivity and specificity of 100% for distinguishing CM from UM in Thai adults and 70% and 75%, respectively, for Ugandan children. Across both populations the likelihood ratio of CM given a positive test (ANG-1<15 ng/mL) was 4.1 (2.7-6.5) and the likelihood ratio of CM given a negative test was 0.29 (0.20-0.42). Moreover, low ANG-1 levels at presentation predicted subsequent mortality in children with CM (p = 0.027)., Conclusions/significance: ANG-1 and the ANG-2/1 ratio are promising clinically informative biomarkers for CM. Additional studies should address their utility as prognostic biomarkers and potential therapeutic targets in severe malaria.

Total and differential white blood cell (WBC) counts are basic and essential indicators in any type of illness resulting from infection. In malaria, WBC counts are generally characterized as low to normal during treatment. WBC-counts data, before and during treatment with artemisinin derivatives, was gathered for patients with either Plasmodium falciparum or Plasmodium vivax infection (at 28-day follow-up), to investigate dynamic changes in WBC count. We analyzed and compared the WBC counts of 1,310 inpatients presenting with uncomplicated P. falciparum and P. vivax malaria at the Hospital for Tropical Diseases, in Bangkok, Thailand. Before-treatment, a statistically significant negative correlation was found between initial WBC count and highest temperature on admission. Before and during treatment, WBC counts were significantly lower in P. falciparum than P. vivax infection on days 0 and 7, but the numerical difference was small. We also found clinically significantly low WBC counts during the acute stages of both types of malaria, which subsequently normalized by day 28 follow-up. This finding has important clinical implications for the conventional method of estimating parasitemia using an assumed WBC count of 8,000 cells/microL. The most significant finding in our analysis is that WBC counts in acute P. falciparum and P. vivax malaria are significantly lower than previously assumed for estimating malaria-parasite density. However, these abnormalities returned to normal within several weeks after artemisinin-derivative-based treatment.

In a retrospective study of 1415 patients aged 15 and over, we determined the incidence of clinically important hyponatraemia and hypokalaemia in adults with uncomplicated malaria. On admission, serum concentrations of sodium (135-145 mmol/L) and potassium (3.5-5.0 mmol/L) were found outside these reference ranges in 81% of patients. Severe hypokalaemia (K+ <3.0 mmol/L) and severe hyponatraemia (Na+ <125 mmol/L occurred in 4.4% and 0.6% of the patients, respectively. For hypokalaemia (43%) and hyponatraemia (37%), hypovolaemia, blood urea to creatinine ratio and high serum glucose (>100 mg/dL) were all independent factors (P < 0.001). Other independent predictors for hypokalaemia were Plasmodium vivax infection, female gender; and for hyponatraemia, P. falciparum infection, male gender, concentrations of G-6-PD and serum bicarbonate.

To elucidate the relationship between falciparum malaria-associated anemia and serum erythropoietin (Epo) levels and reticulocyte response during acute malaria infection, 87 adults aged 18-65 years presenting with acute, uncomplicated malaria were examined on enrollment and for 28 days of follow-up. The 87 patients were divided into 2 groups: those with anemia (n = 45) and those without (n = 42). Serum samples were taken on admission (Day 0), then on Days 7, 21, and 28, to measure the reticulocyte count, absolute reticulocyte count, reticulocyte hemoglobin content, and erythropoietin level (Epo). The absolute reticulocyte counts for the anemic patients were significantly higher than for those without anemia on Days 0, 7, 21, and 28. The serum Epo levels for the anemic patients were significantly higher than the non-anemic group only on Day 0 (44.39 +/- 4.06 vs 25.91 +/- 4.86 mlU/ml, p < 0.001). Inadequate Epo production was found in 31.03% (27/87) of patients on Day 0, 37.93% (33/87) on Day 7, 43.67% (38/87) on Day 21, and 39.08% (34/87) on Day 28. These results indicate defective Epo production and reticulocyte response in adult patients suffering from acute P. falciparum malaria, which differs from pediatric patients. Our findings may provide the basis for further study into the choice of therapeutic strategies to treat acute P. falciparum malaria-associated anemia with recombinant human Epo to correct refractory anemia due to malaria.

Background: It has frequently been reported that Plasmodium vivax suppressed Plasmodium falciparum and ameliorated disease severity in patients infected with these two species simultaneously. The authors investigate the hypothesis that immunological responses stimulated by P. vivax may play a role in suppressing co-infecting P. falciparum., Methods: Sera, taken sequentially from one of the authors (YN) during experimental infection with P. vivax, were added to in vitro cultures of P. falciparum. Cross-reactive antibodies against P. falciparum antigens, and cytokines were measured in the sera., Results: Significant growth inhibitory effects upon P. falciparum cultures (maximally 68% inhibition as compared to pre-illness average) were observed in the sera collected during an acute episode. Such inhibitory effects showed a strong positive temporal correlation with cross-reactive antibodies, especially IgM against P. falciparum schizont extract and, to a lesser degree, IgM against Merozoite Surface Protein (MSP)-119. Interleukin (IL)-12 showed the highest temporal correlation with P. vivax parasitaemia and with body temperatures in the volunteer., Conclusion: These results suggest the involvement by cross-reactive antibodies, especially IgM, in the interplay between plasmodial species. IL-12 may be one of direct mediators of fever induction by rupturing P. vivax schizonts, at least in some subjects. Future studies, preferably of epidemiological design, to reveal the association between cross-reactive IgM and cross-plasmodial interaction, are warranted.

Artemisinin-based combination therapy (ACT) is currently promoted as a strategy for treating both uncomplicated and severe falciparum malaria, targeting asexual blood-stage Plasmodium falciparum parasites. However, the effect of ACT on sexual-stage parasites remains controversial. To determine the clearance of sexual-stage P. falciparum parasites from 342 uncomplicated, and 217 severe, adult malaria cases, we reviewed and followed peripheral blood sexual-stage parasites for 4 wk after starting ACT. All patients presented with both asexual and sexual stage parasites on admission, and were treated with artesunate-mefloquine as the standard regimen. The results showed that all patients were asymptomatic and negative for asexual forms before discharge from hospital. The percentages of uncomplicated malaria patients positive for gametocytes on days 3, 7, 14, 21, and 28 were 41.5, 13.1, 3.8, 2.0, and 2.0%, while the percentages of gametocyte positive severe malaria patients on days 3, 7, 14, 21, and 28 were 33.6, 8.2, 2.7, 0.9, and 0.9%, respectively. Although all patients were negative for asexual parasites by day 7 after completion of the artesunate-mefloquine course, gametocytemia persisted in some patients. Thus, a gametocytocidal drug, e.g., primaquine, may be useful in combination with an artesunate-mefloquine regimen to clear gametocytes, so blocking transmission more effectively than artesunate alone, in malaria transmission areas.

Plasmodium vivax causes debilitating but usually non-lethal malaria in most of Asia and South America. Prevention of relapse after otherwise effective therapy for the acute attack requires a standard daily dose of primaquine administered over 14 days. This regimen has < 90% efficacy in Thailand, and is widely regarded as ineffective because of poor compliance over the relatively long duration of dosing. We evaluated the efficacy, safety, and tolerability of alternative primaquine dosing regimens combined with artesunate among 399 Thai patients with acute, symptomatic P. vivax malaria. Patients were randomly assigned to one of six treatment groups: all patients received artesunate, 100 mg once a day for 5 days. Groups 1-5 then received primaquine, 30 mg a day for 5, 7, 9, 11, and 14 days, respectively. Group 6 received primaquine, 30 mg twice a day for 7 days. The 28-day cure rates were 85%, 89%, 94%, 100%, and 96%, respectively. Treatment of P. vivax malaria with artesunate for 5 days followed by high-dose primaquine, 30 mg twice a day for 7 days, was highly effective, well-tolerated, and equivalent or superior to the standard regimen of primaquine therapy.

Activation of vascular endothelium and blood cells can result in the formation of microparticles (MPs), which are membrane vesicles with a diameter < 1 microm which can play a pathogenetic role in a variety of infectious and other diseases. In this study, we validated a modified quantitative method called "flow rate based calibration", to measure circulating MPs in plasma of healthy subjects and malaria patients using FACSCalibur flow cytometry. MPs counts obtained from "flow rate based calibration" correlated closely with the standard method (R2 = 0.9, p = 0.001). The median (range) number of MPs in healthy subjects was 163/microl (81-375/microl). We demonstrated a flow rate based calibration for the quantitation of MPs in P. falciparum malaria-infected patients. The median (range) number of MPs was 2,051/microl (222-6,432/microl), n = 28 in patients with falciparum malaria. The number of MPs in plasma from patients with severe falciparum malaria was significantly higher than in uncomplicated falciparum malaria (2,567/microl (366-6,432/microl), n = 18 versus [1,947/microl (222-4,107/microl), n = 10, p < 0.01]. Cellular origin of MPs in malaria patients were mainly derived from red blood cells (35%), platelets (10%), and endothelial cells (5%). There was no significant correlation between the total number of MPs and parasitemia. Flow rate based calibration is a simple, reliable, reproducible method and more affordable to quantitate MPs.

The majority of studies concerning malaria host genetics have focused on individual genes that confer protection against rather than susceptibility to malaria. Establishing the relative impact of genetic versus non-genetic factors on malaria infection and disease is essential to focus effort on key determinant factors. This relative contribution has rarely been evaluated for Plasmodium falciparum and almost never for Plasmodium vivax. We conducted a longitudinal cohort study in a Karen population of 3,484 individuals in a region of mesoendemic malaria, Thailand from 1998 to 2005. The number of P. falciparum and P. vivax clinical cases and the parasite density per person were determined. Statistical analyses were performed to account for the influence of environmental factors and the genetic heritability of the phenotypes was calculated using the pedigree-based variance components model. The genetic contribution to the number of clinical episodes resulting from P. falciparum and P. vivax were 10% and 19% respectively. There was also moderate genetic contribution to the maximum and overall parasite trophozoite density phenotypes for both P. falciparum (16%&16%) and P. vivax (15%&13%). These values, for P. falciparum, were similar to those previously observed in a region of much higher transmission intensity in Senegal, West Africa. Although environmental factors play an important role in acquiring an infection, genetics plays a determinant role in the outcome of an infection with either malaria parasite species prior to the development of immunity.

To determine the efficacy, safety and tolerability of an alternative short-course, artemisinin-based combination therapy for acute uncomplicated Plasmodium falciparum malaria, we compared Artequick--a fixed-dosed combination of artemisinin (80 mg), piperaquine (400 mg), and primaquine (4 mg), per tablet--with a standard regimen of artesunate-mefloquine. A total of 130 patients were randomly assigned to treatment with an orally administered, once-daily, 3-day regimen of either Artequick (Group A: 3.2 mg/Kg/day of artemisinin, 16 mg/Kg/day of piperaquine, and 0.16 mg/Kg/day of primaquine) or artesunate-mefloquine (Group B: artesunate, 4 mg/Kg/day, with mefloquine, 8 mg/Kg/day). Patients receiving each regimen had a rapid clinical and parasitological response. All treatments were well tolerated, and no serious adverse effects occurred. No significant differences were found in fever- and parasite-clearance times between the two study groups. The 28-day cure rates were similarly high, at 98.5% and 100%, in groups A and B, respectively. We conclude that Artequick was as effective and well tolerated as artesunate-mefloquine and could be used as an alternative treatment for multidrug-resistant Plasmodium falciparum malaria in Southeast Asia.

In acute uncomplicated falciparum malaria, there is a continuum from mild to severe malaria. However, no mathematical system is available to predict uncomplicated falciparum malaria patients turning to severe malaria. This study aimed to devise a simple and reliable model of Malaria Severity Prognostic Score (MSPS). The study was performed in adult patients with acute uncomplicated falciparum malaria admitted to the Bangkok Hospital for Tropical Diseases between 2000 and 2005. Total 38 initial clinical parameters were identified to predict the usual recovery or deterioration to severe malaria. The stepwise multiple discriminant analysis was performed to get a linear discriminant equation. The results showed that 4.3% of study patients turned to severe malaria. The MSPS = 4.38 (schizontemia) + 1.62 (gametocytemia) + 1.17 (dehydration) + 0.14 (overweight by body mass index; BMI) + 0.05 (initial pulse rate) + 0.04 (duration of fever before admission) - 0.50 (past history of malaria in last 1 year) - 0.48 (initial serum albumin) - 5.66. Based on the validation study in other malaria patients, the sensitivity and specificity were 88.8% and 88.4%, respectively. We conclude that the MSPS is a simple screening tool for predicting uncomplicated falciparum malaria patients turning to severe malaria. However, the MSPS may need revalidation in different geographical areas before utilized at specific places.

To determine the optimum dose of artemisinin-piperaquine combination therapies for acute uncomplicated Plasmodium falciparum malaria, we examined 7 candidate regimens in 411 patients admitted to the Bangkok Hospital for Tropical Diseases. The studies were performed from May 2005 to October 2005 and November 2005 to June 2006. We compared 3-day courses of artesunate-mefloquine, artemether-lumefantrine (Coartem) and of dihydroartemisinin-piperaquine (Artekin) as reference antimalarial treatments, with candidate regimens using 2-3 day courses of artemisinin-piperaquine, Artequick. Initially, patients receiving each of the regimens had a rapid clinical and parasitological response. All treatments were well tolerated and no serious adverse effects occurred. The 28-day cure rates were < 80% for the 2-day treatments with artemisinin-piperaquine at 2.4 mg/kg and 14.4 mg/kg, respectively, in the first study period and artemisinin-piperaquine at 3.2 mg/kg and 16.0 mg/kg, respectively, but > 98% for the 3-day regimens. These results suggest that a 3-day course of artemisinin-piperaquine at 3.2 mg/kg and 16.0 mg/kg, respectively, deserve further evaluation as an alternative treatment for multidrug-resistant P. falciparum malaria.

Chloroquine remains the drug of choice for the treatment of vivax malaria in Thailand. Mixed infections of falciparum and vivax malaria are also common in South-East Asia. Laboratory confirmation of malaria species is not generally available. This study aimed to find alternative regimens for treating both malaria species by using falciparum antimalarial drugs. From June 2004 to May 2005, 98 patients with Plasmodium vivax were randomly treated with either artemether-lumefantrine (n = 47) or chloroquine (n = 51). Both treatments were followed by 15 mg of primaquine over 14 days. Adverse events and clinical and parasitological outcomes were recorded and revealed similar in both groups. The cure rate was 97.4% for the artemether-lumefantrine treated group and 100% for the chloroquine treated group. We concluded that the combination of artemether-lumefantrine and primaquine was well tolerated, as effective as chloroquine and primaquine, and can be an alternative regimen for treatment of vivax malaria especially in the event that a mixed infection of falciparum and vivax malaria could not be ruled out.

A combination of atovaquone-proguanil (Malarone); GlaxoSmithKline, Research Triangle Park, NC) was previously shown to be highly effective in the treatment of uncomplicated Plasmodium falciparum malaria. However, there are only limited recent efficacy data, particularly from regions of multidrug resistance. In this study, we examined the efficacy of atovaquone-proguanil for the treatment of uncomplicated P. falciparum malaria on the Thailand-Myanmar border. Patients were given directly observed atovaquone-proguanil (1,000 mg/400 mg) once a day for three days and followed-up for four weeks in a non-transmission area. Of 140 eligible patients enrolled in this open-label study, 97.8% (95% confidence interval = 95.4-100%) responded to therapy and remained clear of parasitemia at follow-up. Mean parasite clearance time was 41.9 hours and mean fever clearance time was 37.1 hours. On the basis of genotyping, three cases of treatment failure were identified (1 RIII and 2 RI). These data indicate that atovaquone-proguanil remains highly efficacious for the treatment of multidrug-resistant P. falciparum malaria in Thailand.

We examined a possible association of three single nucleotide polymorphisms (SNPs) of the tumor necrosis factor alpha (TNF) promoter -1031T>C (rs1799964), -863C>A (rs1800630), and -857C>T (rs1799724) with severe malaria in 466 adult patients having Plasmodium falciparum malaria in northwest Thailand. Four TNF promoter alleles comprising these three SNPs were detected in the studied population. The frequency of the TNF U04 allele designated -1031C, -863C, and -857C was found to be significantly greater in patients with cerebral malaria than in patients with mild malaria (12.6%, cerebral malaria vs 5.6%, mild malaria; odds ratio =2.5; P=0.002). The association of U04 with susceptibility to cerebral malaria was not caused by linkage disequilibrium with any specific HLA-B and -DRB1 alleles.

Pyrimethamine resistance in Plasmodium falciparum has previously been shown to have emerged once in Southeast Asia, from where it spread to Africa. Pyrimethamine resistance in this parasite is known to be conferred by mutations in the gene encoding dihydrofolate reductase (dhfr). We have analyzed polymorphisms in dhfr as well as microsatellite haplotypes flanking this gene in a total of 285 isolates from different regions of Melanesia (Papua New Guinea, Vanuatu, and the Solomon Islands) and Southeast Asia (Thailand and Cambodia). Nearly all isolates (92%) in Melanesia were shown to carry a dhfr double mutation (CNRNI [underlining indicates the mutation]) at positions 50, 51, 59, 108, and 164, whereas 98% of Southeast Asian isolates were either triple (CIRNI) or quadruple (CIRNL) mutants. Microsatellite analysis revealed two distinct lineages of dhfr double mutants in Melanesia. One lineage had the same microsatellite haplotype as that previously reported for Southeast Asia and Africa, suggesting the spread of this allele to Melanesia from Southeast Asia. The other lineage had a unique, previously undescribed microsatellite haplotype, indicative of the de novo emergence of pyrimethamine resistance in Melanesia.

16alpha-Bromoepiandrosterone (HE2000) is a synthetic androstane steroid that has immune effects in pre-clinical models of malaria, tuberculosis, and infection with human immunodeficiency virus. In pilot studies, 42 patients with confirmed uncomplicated Plasmodium falciparum malaria were treated with a seven-day course of HE2000 by either buccal administration or intramuscular injection. Of the 42 patients, 41 showed a 50% reduction in blood levels of parasites, the primary endpoint of the study. Of these, 32 (76%) cleared malaria parasites below detectable levels. All febrile patients became afebrile by the end of treatment. There was no reduction in gametocyte forms. Adverse events were transient and mild to moderate in intensity. The anti-malarial response was generally similar with either the intramuscular or buccal routes of administration. HE2000 shows a safety profile and pharmacologic activity worthy of further investigation to understand its role in the treatment of malaria, perhaps in combination with anti-malarial agents.

Azithromycin when used in combination with faster-acting antimalarials has proven efficacious in treating Plasmodium falciparum malaria in phase 2 clinical trials. The aim of this study was to establish optimal combination ratios for azithromycin in combination with either dihydroartemisinin or quinine, to determine the clinical correlates of in vitro drug sensitivity for these compounds, and to assess the cross-sensitivity patterns. Seventy-three fresh P. falciparum isolates originating from patients from the western border regions of Thailand were successfully tested for their drug susceptibility in a histidine-rich protein 2 (HRP2) assay. With overall mean fractional inhibitory concentrations of 0.84 (95% confidence interval [CI]=0.77 to 1.08) and 0.78 (95% CI=0.72 to 0.98), the interactions between azithromycin and dihydroartemisinin, as well as quinine, were classified as additive, with a tendency toward synergism. The strongest tendency toward synergy was seen with a combination ratio of 1:547 for the combination with dihydroartemisinin and 1:44 with quinine. The geometric mean 50% inhibitory concentration (IC50) of azithromycin was 2,570.3 (95% CI=2,175.58 to 3,036.58) ng/ml. The IC50s for mefloquine, quinine, and chloroquine were 11.42, 64.4, and 54.4 ng/ml, respectively, suggesting a relatively high level of background resistance in this patient population. Distinct correlations (R=0.53; P=0.001) between quinine in vitro results and parasite clearance may indicate a compromised sensitivity to this drug. The correlation with dihydroartemisinin data was weaker (R=0.34; P=0.038), and no such correlation was observed for azithromycin. Our in vitro data confirm that azithromycin in combination with artemisinin derivatives or quinine exerts additive to synergistic interactions, shows no cross-sensitivity with traditional antimalarials, and has substantial antimalarial activity on its own.

Liver function tests were performed in 61 vivax, 54 malariae and 15 ovale malaria patients who were admitted to Bangkok Hospital for Tropical Diseases between 2001 and 2004. The objective of the study was to evaluate changes in hepatic biochemical indices before and after treatment with artemisinin derivatives. On admission and prior to treatment, hepatic dysfunction was found among the 3 groups. Serum liver function tests and physical examinations were performed weekly during the 28-day follow-up period. Initially elevated serum bilirubin and diminished albumin returned to normal within 2 weeks of treatment. Serum alkaline phosphatase and aminotransferases returned to within normal limits within 3 weeks. We conclude that patients with Plasmodium vivax, P. malariae and P. ovale infections had slightly elevated serum bilirubin, aminotransferase and alkaline phosphatase levels, and hypoalbuminemia. These minor abnormalities returned to normal within a few weeks after treatment with therapies based on artemisinin derivatives.

Background: Intra-rectal artesunate has been developed as a potentially life-saving treatment of severe malaria in rural village settings where administration of parenteral antimalarial drugs is not possible. We studied the population pharmacokinetics of intra-rectal artesunate and the relationship with parasitological responses in patients with moderately severe falciparum malaria., Methods and Findings: Adults and children in Africa and Southeast Asia with moderately severe malaria were recruited in two Phase II studies (12 adults from Southeast Asia and 11 children from Africa) with intensive sampling protocols, and three Phase III studies (44 children from Southeast Asia, and 86 children and 26 adults from Africa) with sparse sampling. All patients received 10 mg/kg artesunate as a single intra-rectal dose of suppositories. Venous blood samples were taken during a period of 24 h following dosing. Plasma artesunate and dihydroartemisinin (DHA, the main biologically active metabolite) concentrations were measured by high-performance liquid chromatography with electrochemical detection. The pharmacokinetic properties of DHA were determined using nonlinear mixed-effects modelling. Artesunate is rapidly hydrolysed in vivo to DHA, and this contributes the majority of antimalarial activity. For DHA, a one-compartment model assuming complete conversion from artesunate and first-order appearance and elimination kinetics gave the best fit to the data. The mean population estimate of apparent clearance (CL/F) was 2.64 (l/kg/h) with 66% inter-individual variability. The apparent volume of distribution (V/F) was 2.75 (l/kg) with 96% inter-individual variability. The estimated DHA population mean elimination half-life was 43 min. Gender was associated with increased mean CL/F by 1.14 (95% CI: 0.36-1.92) (l/kg/h) for a male compared with a female, and weight was positively associated with V/F. Larger V/Fs were observed for the patients requiring early rescue treatment compared with the remainder, independent of any confounders. No associations between the parasitological responses and the posterior individual estimates of V/F, CL/F, and AUC0-6h were observed., Conclusions: The pharmacokinetic properties of DHA were affected only by gender and body weight. Patients with the lowest area under the DHA concentration curve did not have slower parasite clearance, suggesting that rectal artesunate is well absorbed in most patients with moderately severe malaria. However, a number of modelling assumptions were required due to the large intra- and inter-individual variability of the DHA concentrations.

We retrospectively examined the charts of travelers admitted to the Hospital for Tropical Diseases, Bangkok, Thailand, with malaria during the years 2000-2005. Twenty-one cases of malaria were identified, of which 12 (57%) were Plasmodium vivax infections and 9 (43%) were P. falciparum infections. There was one mixed case with vivax and falciparum infection. Only 1 P. falciparum case had complications. All cases were successfully treated with standard antimalarial drugs. Only 3 of the 21 cases were thought to be acquired in Thailand, the rest were regarded to be imported.

We conducted a study to compare the safety and tolerability of anti-relapse drugs elubaquine and primaquine against Plasmodium vivax malaria. After standard therapy with chloroquine, 30 mg/kg given over 3 days, 141 patients with P. vivax infection were randomized to receive primaquine or elubaquine. The 2 treatment regimens were primaquine 30 mg once daily for 7 days (group A, n = 71), and elubaquine 25 mg once daily for 7 days (group B, n = 70). All patients cleared parasitemia within 7 days after chloroquine treatment. Among patients treated with primaquine, one patient relapsed on day 26; no relapse occurred with elubaquine treatement. Both drugs were well tolerated. Adverse effects occurred only in patients with G6PD deficiency who were treated with primaquine (group A, n = 4), whose mean hematocrit fell significantly on days 7, 8 and 9 (P = 0.015, 0.027, and 0.048, respectively). No significant change in hematocrit was observed in patients with G6PD deficiency who were treated with elubaquine (group B, n = 3) or in patients with normal G6PD. In conclusion, elubaquine, as anti-relapse therapy for P. vivax malaria, was as safe and well tolerated as primaquine and did not cause clinically significant hemolysis.

The pathogenesis of cerebral malaria from Plasmodium falciparum infection is thought to involve inflammation of the central nervous system. Since monocyte chemoattractant protein 1 (MCP-1) is a chemokine strongly involved in the inflammatory process, we here study MCP-1 gene polymorphisms in association with severe or cerebral malaria in Thailand. Malaria patients in the northwest of Thailand were grouped into mild (n=206), severe (165), and cerebral (110) malaria case groups. Five single nucleotide polymorphisms (SNPs) in the promoter (-2518A/G, -2348G/C, -2158C/T, -2076A/T, and -2072T/C), and 1 SNP in intron 1 (764C/G) were analyzed by PCR-RFLP, PCR-SSP, or direct sequencing. The SNP -2158 was a novel polymorphism found in this study. For all SNPs, genotype and allele frequencies were not significantly different between mild and severe or mild and cerebral malaria. Strong linkage disequilibrium was found among 4 SNPs (-2518A/G, -2348G/C, -2076A/T, and 764C/G), resulting in 4 major estimated haplotypes. The most common haplotype was GGAC. The results indicated that MCP-1 gene polymorphisms were not associated with malaria severity, implying that MCP-1 was not a cause of malaria severity in this Thai population.